test(e2e): cross-validate emitted manifests/recipes against real Zeta Lua loaders

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <[email protected]>

README.md

@@ -0,0 +1,133 @@
+# zeta-reconstruct
+
+zeta-reconstruct — convert Arch Linux packages (binary `.pkg.tar.zst` and source `PKGBUILD`/`.SRCINFO`) into Zeta package format.
+
+The tool is a translator. It never runs makepkg, never compiles anything, and never publishes packages. It only converts files and writes them to disk, warning on stderr whenever a dependency or edge case cannot be mapped cleanly.
+
+## Build
+
+Requires Go 1.26 or newer. The only external dependency is `github.com/klauspost/compress` (zstd decoding); everything else uses the Go standard library.
+
+    go build ./cmd/zeta-reconstruct
+
+This writes the `zeta-reconstruct` binary into the current directory. To place it next to the sources instead:
+
+    go build -o ./cmd/zeta-reconstruct/zeta-reconstruct ./cmd/zeta-reconstruct
+
+## Usage
+
+```
+$ zeta-reconstruct --help
+usage: zeta-reconstruct <command> [flags] <input>
+
+Commands:
+  arch-binary  convert an Arch binary package (.pkg.tar.zst) to Zeta
+  arch-src     convert a PKGBUILD/.SRCINFO source recipe to Zeta
+
+Flags:
+  --list       list registered frontends
+  -h, --help   show this help
+
+arch-binary flags:
+  --output <dir>  output directory (default ".")
+  --repo <url>    repository base URL (default "https://raw.githubusercontent.com/gretagen/zeta-packages/refs/heads/main")
+
+arch-src flags:
+  --output <dir>  output directory (default ".")
+  --arch <arch>   target architecture (default "x86_64")
+```
+
+`--list` prints the registered frontends: `arch-binary` and `arch-src`.
+
+    zeta-reconstruct --list
+    zeta-reconstruct arch-binary <input.pkg.tar.zst> --output <dir> [--repo <url>]
+    zeta-reconstruct arch-src <PKGBUILD|.SRCINFO|dir> --output <dir> [--arch <arch>]
+
+For `arch-binary` the input must end in `.pkg.tar.zst`. For `arch-src` the input may be a `PKGBUILD`, a `.SRCINFO`, or a directory containing either; a `.SRCINFO` is preferred when both are present.
+
+### Outputs
+
+- `arch-binary` writes `packages/<name>/<name>-<version>.tar.gz` and a `package.lua` manifest beside it, under the `--output` directory.
+- `arch-src` writes `<name>.recipe` and a generated `build.sh` into the `--output` directory.
+
+### Workflow
+
+- The emitted `package.lua` is an archive-mode manifest consumed by `zeta` (the package manager). `zeta` downloads the tarball at the manifest `url`, verifies its `sha256`, and installs it with `strip = 1`.
+- The emitted `.recipe` plus `build.sh` are consumed by `zeta-makepkg` to build the binary package from source. The recipe declares `build_system = "custom"` and `build_script = "build.sh"`; zeta-makepkg fetches the source, extracts it, and runs the script under `sh` with `DESTDIR` set.
+
+## Field mapping: `.PKGINFO` → `package.lua`
+
+| `.PKGINFO` field | `package.lua` field | Notes |
+| --- | --- | --- |
+| `pkgname` | `name` | |
+| `pkgver` | `version` | verbatim, already in epoch+pkgrel form (e.g. `1.0-1`) |
+| `pkgdesc` | `summary` | |
+| `url` | n/a | not carried over; the manifest `url` is built from `--repo` plus `packages/<name>/<name>-<version>.tar.gz` |
+| `depend` | `deps` | each relation mapped through the Arch→Zeta name table; dropped deps are skipped with a warning |
+| n/a | `archive` | `{ strip = 1 }` |
+| n/a | `sha256` | sha256 of the emitted tarball |
+
+Arch metadata members that are not payload (`.BUILDINFO`, `.MTREE`, `.INSTALL`, `.Changelog`) are skipped during extraction.
+
+## Field mapping: `.SRCINFO`/`PKGBUILD` → `.recipe`
+
+| source field | recipe field | Notes |
+| --- | --- | --- |
+| `pkgname` | `name` | v1 covers exactly one package per recipe |
+| `pkgver` | `version` | upstream version; `pkgrel` is dropped |
+| `pkgdesc` | `summary` | falls back to the package name when empty |
+| `source[0]` | `url` | the text after a `name::` prefix if present, else the whole string; the URL scheme is never stripped |
+| `sha256sums[0]` | `sha256` | the line is omitted entirely when the value is empty or `SKIP`; a non-hex64 value is dropped with a warning |
+| `depends` | `deps` | each relation mapped through the Arch→Zeta name table |
+| n/a | `build_system` | `"custom"` |
+| n/a | `build_script` | `"build.sh"` |
+
+The generated `build.sh` reproduces the PKGBUILD's `prepare()` (if present), `build()` (if present), and `package()` functions with `$pkgdir` pointed at `$DESTDIR`. Function bodies are embedded from the `PKGBUILD` file; a `.SRCINFO`-only input yields stub functions.
+
+## Dependency mapping
+
+Each Arch dependency relation is mapped in this order:
+
+1. An optdepend-style description (`name: description`) is stripped back to the name.
+2. If the name matches a Zeta package name verbatim (checked against the Zeta package index), it passes through unchanged. Version constraints are preserved; a bare Arch `=` is normalized to `==` (Zeta's canonical form).
+3. Otherwise a curated rename table is applied, with a warning.
+4. Otherwise, if the name is on the base-system drop list, it is dropped, with a warning.
+5. Otherwise it passes through with a warning (nothing is silently lost).
+
+### Renames
+
+| Arch | Zeta |
+| --- | --- |
+| `zlib` | `libz` |
+| `xz` | `xz-utils` |
+| `freetype2` | `freetype` |
+| `libxkbcommon` | `xkbcommon` |
+| `libice` | `libICE` |
+| `libsm` | `libSM` |
+| `libx11` … `libxxf86vm` | `libX11` … `libXxf86vm` |
+
+The X11 family is pure case correction: Arch spells it lowercase (`libx11`, `libxau`, `libxext`, `libxrender`, `libxft`, and the rest of the `libx*` set), while the Zeta index uses `libX*`. Names like `libxcb` and `libxml2` are already correct and are deliberately absent from the table.
+
+### Dropped (base system)
+
+These packages are provided outside the package manager, so Zeta has no package for them:
+
+`glibc`, `gcc-libs`, `gcc`, `bash`, `coreutils`, `filesystem`, `linux-api-headers`, `systemd`, `util-linux`, `ncurses`, `readline`, `tzdata`, `ca-certificates`.
+
+## Version and epoch
+
+- Binary packages keep the `.PKGINFO` `pkgver` verbatim, epoch and pkgrel included (`1.0-1`, or `1:1.0-1` when an epoch exists).
+- Source recipes use `version = pkgver` (the upstream version); `pkgrel` is dropped, matching how versions appear in the Zeta package index.
+- An epoch is never folded into the Zeta version. When a `:` epoch is present, a warning is emitted and the version string keeps its epoch form.
+
+## Not yet supported (v1)
+
+The following shapes are not yet supported in v1. They produce an explicit error, except where noted:
+
+- **Split packages** (more than one `pkgname`): error.
+- **VCS sources**: `git+`, `svn+`, `hg+`, `bzr+` protocol prefixes, `<vcs>::<url>` fragments (e.g. `git::https://…`), and dynamic `pkgver()` functions: error.
+- **Multiple sources** (more than one `source` entry): error.
+- **Zero sources**: error (a recipe requires a `url`).
+- **makedepends, optdepends, provides, conflicts, replaces**: parsed but dropped with a warning; Zeta's formats have no fields for them.
+- **Bash-only constructs in PKGBUILD function bodies** (arrays, `[[ ]]`, `local`, process substitution): the generated `build.sh` carries a warning that it may need manual adjustment.
+- **Gentoo ebuilds and void-src packages**: not supported. The frontend registry interface is in place, so future converters can be added as new frontends, but no such converter ships in v1.

cmd/zeta-reconstruct/main.go

@@ -6,6 +6,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"strings"
 
 	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/registry"
 
@@ -39,6 +40,29 @@ func main() {
 	os.Exit(run(os.Args[1:]))
 }
 
+// normalizeArgs reorders args into [flags and their values..., positionals...]
+// because stdlib flag.Parse stops at the first non-flag token, which would
+// misparse flags placed after the positional input.
+func normalizeArgs(args []string, valueFlags map[string]bool) []string {
+	var flags, positionals []string
+	for i := 0; i < len(args); i++ {
+		tok := args[i]
+		if !strings.HasPrefix(tok, "-") || tok == "-" {
+			positionals = append(positionals, tok)
+			continue
+		}
+		flags = append(flags, tok)
+		if !strings.Contains(tok, "=") {
+			name := tok
+			if valueFlags[name] && i+1 < len(args) {
+				i++
+				flags = append(flags, args[i])
+			}
+		}
+	}
+	return append(flags, positionals...)
+}
+
 func run(args []string) int {
 	if len(args) == 0 {
 		fmt.Fprintln(os.Stderr, "error: no command specified")
@@ -67,21 +91,25 @@ func run(args []string) int {
 	fs := flag.NewFlagSet(frontend.Name(), flag.ContinueOnError)
 	fs.SetOutput(os.Stderr)
 	opts := registry.Options{Output: "."}
+	valueFlags := make(map[string]bool)
 	switch frontend.Name() {
 	case "arch-binary":
 		opts.Repo = defaultRepo
 		fs.StringVar(&opts.Repo, "repo", opts.Repo, "repository base URL")
+		valueFlags["--repo"] = true
 	case "arch-src":
 		opts.Arch = "x86_64"
 		fs.StringVar(&opts.Arch, "arch", opts.Arch, "target architecture")
+		valueFlags["--arch"] = true
 	}
 	fs.StringVar(&opts.Output, "output", opts.Output, "output directory")
+	valueFlags["--output"] = true
 	fs.Usage = func() {
 		fmt.Fprintf(os.Stderr, "usage: zeta-reconstruct %s [flags] <input>\n", frontend.Name())
 		fmt.Fprintln(os.Stderr, "Run 'zeta-reconstruct --help' for usage.")
 	}
 
-	if err := fs.Parse(args[1:]); err != nil {
+	if err := fs.Parse(normalizeArgs(args[1:], valueFlags)); err != nil {
 		if err == flag.ErrHelp {
 			fs.Usage()
 			return 0
@@ -100,6 +128,11 @@ func run(args []string) int {
 		fs.Usage()
 		return 2
 	}
+	if frontend.Name() == "arch-binary" && !strings.HasSuffix(rest[0], ".pkg.tar.zst") {
+		fmt.Fprintln(os.Stderr, "error: arch-binary input must end with .pkg.tar.zst")
+		fs.Usage()
+		return 2
+	}
 
 	if err := frontend.Convert(rest[0], opts); err != nil {
 		fmt.Fprintf(os.Stderr, "error: %v\n", err)

cmd/zeta-reconstruct/main_test.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestNormalizeArgs(t *testing.T) {
+	valueFlags := map[string]bool{
+		"--output": true,
+		"--repo":   true,
+		"--arch":   true,
+	}
+
+	tests := []struct {
+		name string
+		in   []string
+		want []string
+	}{
+		{
+			name: "flags after positional",
+			in:   []string{"input.pkg.tar.zst", "--output", "/tmp/out"},
+			want: []string{"--output", "/tmp/out", "input.pkg.tar.zst"},
+		},
+		{
+			name: "flags before positional",
+			in:   []string{"--output", "/tmp/out", "input.pkg.tar.zst"},
+			want: []string{"--output", "/tmp/out", "input.pkg.tar.zst"},
+		},
+		{
+			name: "flag=value form",
+			in:   []string{"input.pkg.tar.zst", "--output=/tmp/out"},
+			want: []string{"--output=/tmp/out", "input.pkg.tar.zst"},
+		},
+		{
+			name: "unknown flag stays a flag",
+			in:   []string{"input.pkg.tar.zst", "--bogus"},
+			want: []string{"--bogus", "input.pkg.tar.zst"},
+		},
+		{
+			name: "value-taking flag at end without value",
+			in:   []string{"input.pkg.tar.zst", "--output"},
+			want: []string{"--output", "input.pkg.tar.zst"},
+		},
+		{
+			name: "mixed flags and positionals keep order",
+			in:   []string{"--repo", "https://x", "a.zst", "--output", "/tmp/out", "b.zst"},
+			want: []string{"--repo", "https://x", "--output", "/tmp/out", "a.zst", "b.zst"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := normalizeArgs(tt.in, valueFlags)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Fatalf("normalizeArgs(%v) = %v, want %v", tt.in, got, tt.want)
+			}
+		})
+	}
+}

go.mod

@@ -1,3 +1,5 @@
 module git.spectoria.dev/huntedbytheirs/zeta-reconstruct
 
 go 1.26.5
+
+require github.com/klauspost/compress v1.19.2

go.sum

@@ -0,0 +1,2 @@
+github.com/klauspost/compress v1.19.2 h1:hMRETovs/pu/dVWN7zIT1PGG8t509MwT6bO7XSi26R8=
+github.com/klauspost/compress v1.19.2/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=

internal/arch/binary/convert.go

@@ -0,0 +1,251 @@
+package binary
+
+import (
+	"archive/tar"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/klauspost/compress/zstd"
+
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/depmap"
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/registry"
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/tarball"
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/zeta"
+)
+
+// rootMetadata is the set of Arch metadata members that live at the ROOT of
+// a .pkg.tar.zst and are never part of the installed payload. Only these
+// names at the root are skipped; a dot-file with the same name deeper in the
+// tree is real content.
+var rootMetadata = map[string]bool{
+	".PKGINFO":   true,
+	".BUILDINFO": true,
+	".MTREE":     true,
+	".INSTALL":   true,
+	".Changelog": true,
+}
+
+// Convert converts an Arch binary package (.pkg.tar.zst) into a Zeta binary
+// package:
+//
+//  1. Open input with a zstd reader and walk the tar members.
+//  2. Read and parse the .PKGINFO member (member name ".PKGINFO" or
+//     "./.PKGINFO"). Its pkgver is the Zeta version, verbatim (epoch+pkgrel
+//     form, e.g. "1.0-1").
+//  3. Extract every other member (root dot-metadata skipped) into a temp dir,
+//     preserving paths, modes and symlinks.
+//  4. Repack the payload with tarball.Write into
+//     <out>/packages/<name>/<name>-<version>.tar.gz.
+//  5. Emit an archive-mode package.lua next to the tarball, with depends
+//     mapped through depmap.MapDep.
+//
+// An epoch (":" in pkgver) is warned about and never folded: Zeta versioning
+// cannot represent it.
+func Convert(input string, opts registry.Options) error {
+	f, err := os.Open(input)
+	if err != nil {
+		return fmt.Errorf("convert: open %s: %w", input, err)
+	}
+	zr, err := zstd.NewReader(f)
+	if err != nil {
+		_ = f.Close()
+		return fmt.Errorf("convert: zstd %s: %w", input, err)
+	}
+	defer func() {
+		zr.Close()
+		_ = f.Close()
+	}()
+	tr := tar.NewReader(zr)
+
+	warn := func(msg string) { fmt.Fprintf(os.Stderr, "warning: %s\n", msg) }
+
+	extracted, err := os.MkdirTemp("", "zr-arch-binary-*")
+	if err != nil {
+		return fmt.Errorf("convert: temp dir: %w", err)
+	}
+	defer os.RemoveAll(extracted)
+
+	var info *PKGInfo
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return fmt.Errorf("convert: read %s: %w", input, err)
+		}
+
+		name := cleanMemberName(hdr.Name)
+
+		// Root dot-metadata: never extracted. .PKGINFO is read from the
+		// stream here; the other four are skipped without reading.
+		if isRootMetadata(name) {
+			if name == ".PKGINFO" {
+				content, err := io.ReadAll(tr)
+				if err != nil {
+					return fmt.Errorf("convert: read .PKGINFO: %w", err)
+				}
+				info, err = Parse(string(content), warn)
+				if err != nil {
+					return fmt.Errorf("convert: parse .PKGINFO: %w", err)
+				}
+			}
+			continue
+		}
+
+		if err := extractMember(extracted, name, hdr, tr); err != nil {
+			return err
+		}
+	}
+
+	if info == nil {
+		return errors.New("convert: archive has no .PKGINFO member")
+	}
+	if info.Name == "" {
+		return errors.New("convert: .PKGINFO has no pkgname")
+	}
+
+	if strings.Contains(info.Version, ":") {
+		warn(fmt.Sprintf("package %s has epoch in version; epoch is not representable in Zeta versioning", info.Name))
+	}
+
+	// Deps: map each declared dependency through the Arch→Zeta name map.
+	// Dropped deps are skipped (MapDep already warned).
+	var deps []string
+	for _, d := range info.Depends {
+		if mapped, ok := depmap.MapDep(d, warn); ok {
+			deps = append(deps, mapped)
+		}
+	}
+
+	pkgDir := filepath.Join(opts.Output, "packages", info.Name)
+	if err := os.MkdirAll(pkgDir, 0o755); err != nil {
+		return fmt.Errorf("convert: mkdir %s: %w", pkgDir, err)
+	}
+
+	tarballPath := filepath.Join(pkgDir, info.Name+"-"+info.Version+".tar.gz")
+	sum, err := tarball.Write(extracted, tarballPath)
+	if err != nil {
+		return fmt.Errorf("convert: repack payload: %w", err)
+	}
+
+	m := &zeta.Manifest{
+		Name:    info.Name,
+		Version: info.Version,
+		Summary: info.Desc,
+		URL:     opts.Repo + "/packages/" + info.Name + "/" + info.Name + "-" + info.Version + ".tar.gz",
+		SHA256:  sum,
+		Deps:    deps,
+		Archive: &zeta.Archive{Strip: 1},
+	}
+
+	src, err := m.Emit()
+	if err != nil {
+		return fmt.Errorf("convert: emit manifest: %w", err)
+	}
+	manifestPath := filepath.Join(pkgDir, "package.lua")
+	if err := os.WriteFile(manifestPath, []byte(src), 0o644); err != nil {
+		return fmt.Errorf("convert: write %s: %w", manifestPath, err)
+	}
+	return nil
+}
+
+// cleanMemberName strips the "./" prefix (and any leading slashes) GNU tar
+// prepends, yielding the canonical root-relative member name.
+func cleanMemberName(name string) string {
+	for strings.HasPrefix(name, "./") {
+		name = name[2:]
+	}
+	return name
+}
+
+// isRootMetadata reports whether name is one of the Arch metadata members at
+// the ROOT of the archive (no directory component).
+func isRootMetadata(name string) bool {
+	if name == "" || name == "." {
+		return false
+	}
+	if strings.Contains(name, "/") {
+		return false
+	}
+	return rootMetadata[name]
+}
+
+// extractMember extracts a single tar member under root, preserving paths,
+// modes and symlinks. Directories are created; hard links, FIFOs and device
+// nodes are skipped, matching tarball.Write's policy.
+func extractMember(root, name string, hdr *tar.Header, r io.Reader) error {
+	if name == "" || name == "." {
+		return nil // the archive root entry itself
+	}
+	if strings.HasPrefix(name, "/") || !relativeInside(name) {
+		return fmt.Errorf("convert: member %q escapes the extraction root", name)
+	}
+
+	target := filepath.Join(root, filepath.FromSlash(name))
+	switch hdr.Typeflag {
+	case tar.TypeDir:
+		mode := os.FileMode(hdr.Mode).Perm()
+		if mode == 0 {
+			mode = 0o755
+		}
+		return os.MkdirAll(target, mode)
+
+	case tar.TypeReg, tar.TypeRegA:
+		if err := os.MkdirAll(filepath.Dir(target), 0o755); err != nil {
+			return err
+		}
+		mode := os.FileMode(hdr.Mode).Perm()
+		if mode == 0 {
+			mode = 0o644
+		}
+		_ = os.Remove(target) // never write through a pre-existing symlink
+		f, err := os.OpenFile(target, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, mode)
+		if err != nil {
+			return fmt.Errorf("convert: extract %s: %w", name, err)
+		}
+		if _, err := io.Copy(f, r); err != nil {
+			_ = f.Close()
+			return fmt.Errorf("convert: extract %s: %w", name, err)
+		}
+		return f.Close()
+
+	case tar.TypeSymlink:
+		if err := os.MkdirAll(filepath.Dir(target), 0o755); err != nil {
+			return err
+		}
+		_ = os.Remove(target)
+		if err := os.Symlink(hdr.Linkname, target); err != nil {
+			return fmt.Errorf("convert: extract symlink %s: %w", name, err)
+		}
+		return nil
+
+	default:
+		// Hard links, FIFOs, devices, sparse files: skipped like the
+		// repack step.
+		return nil
+	}
+}
+
+// relativeInside reports whether the slash-separated relative path p never
+// climbs above its root. Port of ZETA/lib/path.lua relative_inside.
+func relativeInside(p string) bool {
+	depth := 0
+	for _, seg := range strings.Split(p, "/") {
+		switch seg {
+		case "..":
+			depth--
+			if depth < 0 {
+				return false
+			}
+		case "", ".":
+		default:
+			depth++
+		}
+	}
+	return true
+}

internal/arch/binary/convert_test.go

@@ -0,0 +1,204 @@
+package binary
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"crypto/sha256"
+	"encoding/hex"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/klauspost/compress/zstd"
+
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/registry"
+)
+
+const fixturePkg = "../../../testdata/hello-1.0-1-x86_64.pkg.tar.zst"
+
+func TestConvert(t *testing.T) {
+	out := t.TempDir()
+	err := Convert(fixturePkg, registry.Options{Output: out, Repo: "https://example.org/repo"})
+	if err != nil {
+		t.Fatalf("Convert() error = %v, want nil", err)
+	}
+
+	manifestPath := filepath.Join(out, "packages", "hello", "package.lua")
+	tarballPath := filepath.Join(out, "packages", "hello", "hello-1.0-1.tar.gz")
+
+	content, err := os.ReadFile(manifestPath)
+	if err != nil {
+		t.Fatalf("package.lua not written: %v", err)
+	}
+	src := string(content)
+
+	if !strings.Contains(src, "archive = { strip = 1 }") {
+		t.Errorf("package.lua does not contain archive mode marker:\n%s", src)
+	}
+	if !strings.Contains(src, `name    = "hello"`) {
+		t.Errorf("package.lua does not contain name field:\n%s", src)
+	}
+
+	if _, err := os.Stat(tarballPath); err != nil {
+		t.Fatalf("tarball not written: %v", err)
+	}
+
+	// The sha256 field must equal a fresh hash of the written tarball.
+	got := extractField(t, src, "sha256")
+	want := fileSHA256(t, tarballPath)
+	if got != want {
+		t.Errorf("package.lua sha256 = %q, sha256(tarball) = %q", got, want)
+	}
+
+	// Deps: glibc dropped, zlib renamed to libz.
+	if !strings.Contains(src, `"libz"`) {
+		t.Errorf("package.lua deps does not contain mapped libz:\n%s", src)
+	}
+	if strings.Contains(src, "glibc") {
+		t.Errorf("package.lua still contains dropped glibc:\n%s", src)
+	}
+
+	// Cross-tool validation: the emitted manifest must load through the
+	// real Zeta manifest loader.
+	lua, err := exec.LookPath("lua")
+	if err != nil {
+		t.Skip("lua not available; skipping cross-tool validation")
+	}
+	probe := `package.path="/home/specter/Public/ZETA/lib/?.lua;"..package.path; ` +
+		`local m=require("manifest"); assert(m.load(` + quoteLua(manifestPath) + `))`
+	cmd := exec.Command(lua, "-e", probe)
+	if b, err := cmd.CombinedOutput(); err != nil {
+		t.Fatalf("real Zeta manifest.load rejected the emitted manifest: %v\n%s", err, b)
+	}
+
+	// The tarball must be a valid gzip+tar whose content matches the input
+	// payload (usr/bin/hello).
+	verifyTarballPayload(t, tarballPath)
+}
+
+func TestConvertMissingPKGINFO(t *testing.T) {
+	// A zstd-compressed tar without a .PKGINFO member.
+	var buf strings.Builder
+	tw := tar.NewWriter(&buf)
+	body := "#!/bin/sh\n"
+	if err := tw.WriteHeader(&tar.Header{Name: "usr/bin/x", Mode: 0o755, Size: int64(len(body))}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := tw.Write([]byte(body)); err != nil {
+		t.Fatal(err)
+	}
+	if err := tw.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	enc, err := zstd.NewWriter(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	compressed := enc.EncodeAll([]byte(buf.String()), nil)
+
+	pkg := filepath.Join(t.TempDir(), "noinfo.pkg.tar.zst")
+	if err := os.WriteFile(pkg, compressed, 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	err = Convert(pkg, registry.Options{Output: t.TempDir(), Repo: "https://example.org/repo"})
+	if err == nil {
+		t.Fatal("Convert() error = nil, want error for archive without .PKGINFO")
+	}
+	if !strings.Contains(err.Error(), "PKGINFO") {
+		t.Errorf("Convert() error = %q, want it to name the missing .PKGINFO", err)
+	}
+}
+
+func TestConvertMissingInput(t *testing.T) {
+	err := Convert(filepath.Join(t.TempDir(), "nope.pkg.tar.zst"),
+		registry.Options{Output: t.TempDir(), Repo: "https://example.org/repo"})
+	if err == nil {
+		t.Fatal("Convert() error = nil, want error for missing input file")
+	}
+}
+
+// extractField pulls the value of a `key = "value",` line from an emitted
+// package.lua.
+func extractField(t *testing.T, src, key string) string {
+	t.Helper()
+	for _, line := range strings.Split(src, "\n") {
+		line = strings.TrimSpace(line)
+		if !strings.HasPrefix(line, key) {
+			continue
+		}
+		i := strings.Index(line, `"`)
+		j := strings.LastIndex(line, `"`)
+		if i < 0 || j <= i {
+			t.Fatalf("field %q has no quoted value in %q", key, line)
+		}
+		return line[i+1 : j]
+	}
+	t.Fatalf("field %q not found in package.lua", key)
+	return ""
+}
+
+// fileSHA256 returns the lowercase hex sha256 of the file at path.
+func fileSHA256(t *testing.T, path string) string {
+	t.Helper()
+	f, err := os.Open(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	h := sha256.New()
+	if _, err := io.Copy(h, f); err != nil {
+		t.Fatal(err)
+	}
+	return hex.EncodeToString(h.Sum(nil))
+}
+
+// quoteLua renders a path as a safe single-quoted Lua string literal.
+func quoteLua(s string) string {
+	return `'` + strings.ReplaceAll(s, `\`, `\\`) + `'`
+}
+
+// verifyTarballPayload re-opens the emitted tarball and asserts the payload
+// file survived with the right content.
+func verifyTarballPayload(t *testing.T, path string) {
+	t.Helper()
+	f, err := os.Open(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	gz, err := gzip.NewReader(f)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer gz.Close()
+
+	var found bool
+	tr := tar.NewReader(gz)
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatal(err)
+		}
+		if strings.TrimPrefix(hdr.Name, "./") == "usr/bin/hello" {
+			found = true
+			b, err := io.ReadAll(tr)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !strings.Contains(string(b), "hello") {
+				t.Errorf("payload usr/bin/hello content = %q", b)
+			}
+		}
+	}
+	if !found {
+		t.Error("payload member usr/bin/hello missing from tarball")
+	}
+}

internal/arch/binary/frontend.go

@@ -3,8 +3,6 @@
 package binary
 
 import (
-	"errors"
-
 	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/registry"
 )
 
@@ -13,9 +11,10 @@ type frontend struct{}
 
 func (frontend) Name() string { return "arch-binary" }
 
+// Convert converts an Arch .pkg.tar.zst into a Zeta binary package
+// (payload tarball + archive-mode package.lua) under opts.Output.
 func (frontend) Convert(input string, opts registry.Options) error {
-	// Implemented in a later todo (.pkg.tar.zst -> tarball + package.lua).
+	return Convert(input, opts)
-	return errors.New("not implemented")
 }
 
 func init() {

internal/arch/binary/pkginfo.go

@@ -0,0 +1,74 @@
+package binary
+
+import (
+	"errors"
+	"strings"
+)
+
+// PKGInfo is the parsed content of an ALPM .PKGINFO file, the metadata
+// member at the root of an Arch .pkg.tar.zst package.
+type PKGInfo struct {
+	Name, Version, Desc, URL, Arch                     string
+	Depends, OptDepends, Provides, Conflicts, Replaces []string
+}
+
+// Parse parses ALPM .PKGINFO content: lines of "key = value", full-line
+// `#` comments and blank lines ignored. Multi-value keys (depend,
+// optdepend, provides, conflicts, replaces, license) accumulate across
+// lines; single-value keys (pkgname, pkgver, pkgdesc, url, arch, pkgbase)
+// take the last occurrence. pkgver is the FULL version, already in
+// epoch+pkgrel form (e.g. "1.0-1" or "1:1.0.0-1"), and is passed through
+// verbatim. Unknown keys are ignored. Malformed lines (no '=') are
+// reported through warn and skipped, not fatal.
+//
+// Parse returns an error if pkgname is missing: a .PKGINFO without a name
+// is invalid for conversion.
+func Parse(src string, warn func(string)) (*PKGInfo, error) {
+	info := &PKGInfo{}
+	haveName := false
+	for _, line := range strings.Split(src, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		eq := strings.Index(line, "=")
+		if eq < 0 {
+			if warn != nil {
+				warn("malformed .PKGINFO line (no '='): " + line)
+			}
+			continue
+		}
+		key := strings.TrimSpace(line[:eq])
+		value := strings.TrimSpace(line[eq+1:])
+		switch key {
+		case "pkgname":
+			info.Name = value
+			haveName = true
+		case "pkgver":
+			info.Version = value
+		case "pkgdesc":
+			info.Desc = value
+		case "url":
+			info.URL = value
+		case "arch":
+			info.Arch = value
+		case "depend":
+			info.Depends = append(info.Depends, value)
+		case "optdepend":
+			info.OptDepends = append(info.OptDepends, value)
+		case "provides":
+			info.Provides = append(info.Provides, value)
+		case "conflicts":
+			info.Conflicts = append(info.Conflicts, value)
+		case "replaces":
+			info.Replaces = append(info.Replaces, value)
+		default:
+			// pkgbase, license, builddate, packager, size, xdata and any
+			// unknown keys are not represented in PKGInfo; ignore them.
+		}
+	}
+	if !haveName {
+		return nil, errors.New("pkginfo: missing pkgname")
+	}
+	return info, nil
+}

internal/arch/binary/pkginfo_test.go

@@ -0,0 +1,135 @@
+package binary
+
+import (
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// readFixture loads a committed .PKGINFO fixture relative to the repo root.
+func readFixture(t *testing.T, path string) string {
+	t.Helper()
+	b, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read fixture %s: %v", path, err)
+	}
+	return string(b)
+}
+
+func TestPKGInfo(t *testing.T) {
+	tests := []struct {
+		name string
+		src  string
+		want *PKGInfo
+	}{
+		{
+			name: "hello fixture",
+			src:  readFixture(t, "../../../testdata/pkginfo/hello.PKGINFO"),
+			want: &PKGInfo{
+				Name:    "hello",
+				Version: "1.0-1",
+				Desc:    "A tiny demonstration program",
+				URL:     "https://example.org",
+				Arch:    "x86_64",
+				Depends: []string{"glibc", "zlib"},
+			},
+		},
+		{
+			name: "multi fixture",
+			src:  readFixture(t, "../../../testdata/pkginfo/multi.PKGINFO"),
+			want: &PKGInfo{
+				Name:       "multiload",
+				Version:    "2.3-1",
+				Desc:       "Multi dep test",
+				URL:        "https://example.org",
+				Arch:       "x86_64",
+				Depends:    []string{"glibc", "pcre2>=10.42"},
+				OptDepends: []string{"python: for scripting"},
+				Provides:   []string{"multiload"},
+			},
+		},
+		{
+			name: "epoch fixture keeps colon",
+			src:  readFixture(t, "../../../testdata/pkginfo/epoch.PKGINFO"),
+			want: &PKGInfo{
+				Name:    "epochtool",
+				Version: "1:1.0.0-1",
+				Desc:    "Epoch test",
+				URL:     "https://example.org",
+				Arch:    "x86_64",
+				Depends: []string{"glibc"},
+			},
+		},
+		{
+			name: "comments blank lines unknown keys and whitespace",
+			src: strings.Join([]string{
+				"# full-line comment",
+				"",
+				"  pkgname =  spaced  ",
+				"pkgver = 9.9-9",
+				"pkgbase = ignored-base",
+				"license = GPL2",
+				"license = MIT",
+				"builddate = 1724000000",
+				"unknown = whatever",
+				"conflicts = oldtool",
+				"replaces = replaced",
+			}, "\n") + "\n",
+			want: &PKGInfo{
+				Name:      "spaced",
+				Version:   "9.9-9",
+				Conflicts: []string{"oldtool"},
+				Replaces:  []string{"replaced"},
+			},
+		},
+		{
+			name: "last occurrence wins for single-value keys",
+			src:  "pkgname = first\npkgver = 1.0-1\npkgname = second\npkgver = 2.0-2\n",
+			want: &PKGInfo{
+				Name:    "second",
+				Version: "2.0-2",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := Parse(tt.src, func(msg string) {
+				t.Errorf("unexpected warn: %s", msg)
+			})
+			if err != nil {
+				t.Fatalf("Parse() error = %v, want nil", err)
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Parse() = %#v, want %#v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestPKGInfoMalformedLineWarns(t *testing.T) {
+	src := "pkgname = ok\npkgver = 1.0-1\ngarbage no equals\n"
+	var warns []string
+	info, err := Parse(src, func(msg string) {
+		warns = append(warns, msg)
+	})
+	if err != nil {
+		t.Fatalf("Parse() error = %v, want nil", err)
+	}
+	if len(warns) != 1 {
+		t.Fatalf("warn called %d times, want exactly 1: %v", len(warns), warns)
+	}
+	if !strings.Contains(warns[0], "garbage no equals") {
+		t.Errorf("warn message %q does not mention the malformed line", warns[0])
+	}
+	if info.Name != "ok" || info.Version != "1.0-1" {
+		t.Errorf("Parse() = %#v, want name ok / version 1.0-1 despite malformed line", info)
+	}
+}
+
+func TestPKGInfoMissingName(t *testing.T) {
+	_, err := Parse("pkgver = 1.0-1\n", func(string) {})
+	if err == nil {
+		t.Fatal("Parse() error = nil, want error for missing pkgname")
+	}
+}

internal/arch/src/buildscript.go

@@ -0,0 +1,193 @@
+// Package src converts Arch Linux source packages (PKGBUILD/.SRCINFO) into
+// Zeta recipes.
+package src
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"regexp"
+	"strings"
+)
+
+// SrcInfo holds the parsed metadata of an Arch source package, produced by
+// the .SRCINFO parser / PKGBUILD fallback (todo 10). The field layout is
+// fixed by the plan; the parallel task's srcinfo.go populates this struct.
+type SrcInfo struct {
+	PkgBase     string
+	PkgNames    []string
+	Version     string
+	Rel         string
+	Epoch       string
+	Desc        string
+	URL         string
+	Arch        []string
+	Depends     []string
+	Makedepends []string
+	Optdepends  []string
+	Provides    []string
+	Conflicts   []string
+	Replaces    []string
+	Sources     []string
+	SHA256Sums  []string
+}
+
+// Generate emits a self-contained POSIX-sh build script (build.sh) that
+// reproduces the PKGBUILD's prepare/build/package steps under zeta-makepkg's
+// custom build contract:
+//
+//	cd <source_dir> && DESTDIR=<stage> sh build.sh
+//
+// so $PWD at script start is the extracted source root and $DESTDIR is the
+// staging tree. Arch's package() installs into $pkgdir; mapping
+// pkgdir="$DESTDIR" is the whole trick.
+//
+// Function bodies declared by the PKGBUILD at pkgbuildPath are embedded
+// verbatim; missing functions become no-op stubs and are not called. If an
+// embedded body uses bash-only constructs, a warning is printed to stderr but
+// the script is still emitted.
+func Generate(s *SrcInfo, pkgbuildPath string) (string, error) {
+	if s == nil {
+		return "", errors.New("arch/src: nil SrcInfo")
+	}
+	raw, err := os.ReadFile(pkgbuildPath)
+	if err != nil {
+		return "", fmt.Errorf("arch/src: read PKGBUILD %s: %w", pkgbuildPath, err)
+	}
+	funcs, err := extractFunctions(string(raw))
+	if err != nil {
+		return "", err
+	}
+	if hasBashOnly(funcs) {
+		fmt.Fprintln(os.Stderr, "warning: build.sh embeds bash-only constructs; may need manual adjustment under POSIX sh")
+	}
+
+	var b strings.Builder
+	b.WriteString("#!/bin/sh\n")
+	b.WriteString("set -eu\n")
+	b.WriteString("\n")
+	b.WriteString("pkgname=" + shQuote(pkgName(s)) + "\n")
+	b.WriteString("pkgver=" + shQuote(s.Version) + "\n")
+	b.WriteString("pkgrel=" + shQuote(s.Rel) + "\n")
+	b.WriteString("arch=" + shQuote(strings.Join(s.Arch, " ")) + "\n")
+	b.WriteString("url=" + shQuote(s.URL) + "\n")
+	b.WriteString("\n")
+	b.WriteString("srcdir=\"$PWD\"\n")
+	b.WriteString("pkgdir=\"$DESTDIR\"\n")
+	b.WriteString("\n")
+	b.WriteString("msg() { :; }\n")
+	b.WriteString("\n")
+
+	var calls []string
+	for _, f := range funcs {
+		if f.present {
+			b.WriteString(f.body)
+			calls = append(calls, f.name)
+		} else {
+			fmt.Fprintf(&b, "%s() { :; }\n", f.name)
+		}
+		b.WriteString("\n")
+	}
+	for _, name := range calls {
+		b.WriteString(name + "\n")
+	}
+	return b.String(), nil
+}
+
+// pkgName prefers the pkgname section value; fall back to pkgbase.
+func pkgName(s *SrcInfo) string {
+	if len(s.PkgNames) > 0 {
+		return s.PkgNames[0]
+	}
+	return s.PkgBase
+}
+
+// shQuote single-quotes a value for safe embedding in sh source.
+func shQuote(v string) string {
+	return "'" + strings.ReplaceAll(v, "'", `'\''`) + "'"
+}
+
+// pkgFunc is one extracted PKGBUILD function: its verbatim text (including
+// the "name() {" opening and closing "}") and whether it was present.
+type pkgFunc struct {
+	name    string
+	body    string
+	present bool
+}
+
+// extractFunctions pulls prepare/build/package bodies out of a PKGBUILD.
+// Each body runs from the "name() {" opener to the first line starting with
+// "}" at column 0, the standard makepkg layout heuristic.
+func extractFunctions(src string) ([]pkgFunc, error) {
+	names := []string{"prepare", "build", "package"}
+	out := make([]pkgFunc, 0, len(names))
+	for _, name := range names {
+		body, present, err := extractFunc(src, name)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, pkgFunc{name: name, body: body, present: present})
+	}
+	return out, nil
+}
+
+func extractFunc(src, name string) (string, bool, error) {
+	startRe := regexp.MustCompile(`(?m)^` + regexp.QuoteMeta(name) + `\(\s*\)\s*\{`)
+	loc := startRe.FindStringIndex(src)
+	if loc == nil {
+		return "", false, nil
+	}
+	end := findClosingBrace(src, loc[1])
+	if end < 0 {
+		return "", false, fmt.Errorf("arch/src: %s() { has no closing '}' at column 0", name)
+	}
+	return src[loc[0]:end], true, nil
+}
+
+// findClosingBrace returns the offset just past the first line starting with
+// "}" (column 0), scanning from from. Returns -1 if none is found.
+func findClosingBrace(src string, from int) int {
+	lineStart := from
+	for lineStart <= len(src) {
+		lineEnd := strings.IndexByte(src[lineStart:], '\n')
+		if lineEnd < 0 {
+			if strings.HasPrefix(src[lineStart:], "}") {
+				return len(src)
+			}
+			return -1
+		}
+		line := src[lineStart : lineStart+lineEnd]
+		if strings.HasPrefix(line, "}") {
+			return lineStart + lineEnd + 1 // include the newline
+		}
+		lineStart += lineEnd + 1
+	}
+	return -1
+}
+
+// bashOnlyPatterns matches constructs that are valid in bash but not POSIX sh.
+var bashOnlyPatterns = []*regexp.Regexp{
+	regexp.MustCompile(`\[\[`),                                    // [[ test ]]
+	regexp.MustCompile(`\$\{[A-Za-z_][A-Za-z0-9_]*\[[^]\n]+\]\}`), // ${arr[@]} / ${arr[0]}
+	regexp.MustCompile(`(^|[^A-Za-z0-9_])local[ \t]+`),            // local var
+	regexp.MustCompile(`(^|[^A-Za-z0-9_])declare[ \t]+`),          // declare -a ...
+	regexp.MustCompile(`(^|[ \t;&])[A-Za-z_][A-Za-z0-9_]*=\(`),    // arr=(...)
+	regexp.MustCompile(`<\(|>\(`),                                 // process substitution
+	regexp.MustCompile(`\$\'`),                                    // $'\n' ANSI-C quoting
+}
+
+// hasBashOnly reports whether any extracted function body uses a bash-only
+// construct.
+func hasBashOnly(funcs []pkgFunc) bool {
+	for _, f := range funcs {
+		if !f.present {
+			continue
+		}
+		for _, re := range bashOnlyPatterns {
+			if re.MatchString(f.body) {
+				return true
+			}
+		}
+	}
+	return false
+}

internal/arch/src/buildscript_test.go

@@ -0,0 +1,146 @@
+package src
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+const (
+	mytoolSRCINFO  = "../../../testdata/srcinfo/mytool/.SRCINFO"
+	mytoolPKGBUILD = "../../../testdata/srcinfo/mytool/PKGBUILD"
+	goldenPath     = "../../../testdata/golden/mytool.build.sh"
+)
+
+// minimalSrcInfo is a test-local .SRCINFO reader. The real parser (todo 10,
+// srcinfo.go) may not exist yet when this test compiles, so the test keeps a
+// tiny reader for the fields Generate needs. It mirrors the documented SrcInfo
+// layout so it converges with the real parser.
+func minimalSrcInfo(t *testing.T, path string) *SrcInfo {
+	t.Helper()
+	data, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read %s: %v", path, err)
+	}
+	s := &SrcInfo{}
+	for _, line := range strings.Split(string(data), "\n") {
+		key, value, ok := strings.Cut(strings.TrimSpace(line), "=")
+		if !ok {
+			continue
+		}
+		key, value = strings.TrimSpace(key), strings.TrimSpace(value)
+		switch key {
+		case "pkgbase":
+			s.PkgBase = value
+		case "pkgname":
+			s.PkgNames = append(s.PkgNames, value)
+		case "pkgver":
+			s.Version = value
+		case "pkgrel":
+			s.Rel = value
+		case "arch":
+			s.Arch = append(s.Arch, value)
+		case "url":
+			s.URL = value
+		}
+	}
+	return s
+}
+
+func generateMytool(t *testing.T) string {
+	t.Helper()
+	out, err := Generate(minimalSrcInfo(t, mytoolSRCINFO), mytoolPKGBUILD)
+	if err != nil {
+		t.Fatalf("Generate: %v", err)
+	}
+	return out
+}
+
+func TestBuildScriptGolden(t *testing.T) {
+	out := generateMytool(t)
+
+	if os.Getenv("UPDATE_GOLDEN") == "1" {
+		if err := os.WriteFile(goldenPath, []byte(out), 0o644); err != nil {
+			t.Fatalf("write golden: %v", err)
+		}
+		t.Logf("wrote golden %s", goldenPath)
+		return
+	}
+
+	want, err := os.ReadFile(goldenPath)
+	if err != nil {
+		t.Fatalf("read golden (run: UPDATE_GOLDEN=1 go test ./internal/arch/src/ -run TestBuildScript): %v", err)
+	}
+	if string(want) != out {
+		t.Errorf("generated build.sh does not match golden %s", goldenPath)
+		for i, line := range strings.Split(string(want), "\n") {
+			gotLine := ""
+			if ls := strings.Split(out, "\n"); i < len(ls) {
+				gotLine = ls[i]
+			}
+			if line != gotLine {
+				t.Errorf("first diff at line %d:\n  golden: %q\n  got:    %q", i+1, line, gotLine)
+				break
+			}
+		}
+	}
+}
+
+func TestBuildScriptPassesShSyntax(t *testing.T) {
+	sh, err := exec.LookPath("sh")
+	if err != nil {
+		t.Skip("sh not found in PATH")
+	}
+	out := generateMytool(t)
+	script := filepath.Join(t.TempDir(), "build.sh")
+	if err := os.WriteFile(script, []byte(out), 0o755); err != nil {
+		t.Fatalf("write script: %v", err)
+	}
+	cmd := exec.Command(sh, "-n", script)
+	if output, err := cmd.CombinedOutput(); err != nil {
+		t.Errorf("sh -n %s failed: %v\n%s", script, err, output)
+	}
+}
+
+func TestBuildScriptContainsDestdir(t *testing.T) {
+	out := generateMytool(t)
+	if !strings.Contains(out, `pkgdir="$DESTDIR"`) {
+		t.Errorf("generated script missing pkgdir=\"$DESTDIR\"")
+	}
+	if !strings.Contains(out, "$DESTDIR") {
+		t.Errorf("generated script missing literal $DESTDIR")
+	}
+}
+
+func TestBuildScriptNoFunctions(t *testing.T) {
+	dir := t.TempDir()
+	pkgbuild := filepath.Join(dir, "PKGBUILD")
+	if err := os.WriteFile(pkgbuild, []byte("pkgname=nofunc\npkgver=2.0\npkgrel=1\narch=(x86_64)\n"), 0o644); err != nil {
+		t.Fatalf("write fixture: %v", err)
+	}
+	si := &SrcInfo{PkgNames: []string{"nofunc"}, Version: "2.0", Rel: "1", Arch: []string{"x86_64"}}
+	out, err := Generate(si, pkgbuild)
+	if err != nil {
+		t.Fatalf("Generate: %v", err)
+	}
+	if !strings.Contains(out, `pkgdir="$DESTDIR"`) {
+		t.Errorf("script without functions must still define pkgdir=\"$DESTDIR\"")
+	}
+	if !strings.Contains(out, "package") {
+		t.Errorf("script without functions must still reference package (stub)")
+	}
+}
+
+func TestBuildScriptEmbedsBuildBody(t *testing.T) {
+	out := generateMytool(t)
+	const wantBuild = "build() {\n  cd \"$srcdir\"\n  ./configure --prefix=/usr\n  make\n}"
+	const wantPackage = "package() {\n  cd \"$srcdir\"\n  make DESTDIR=\"$pkgdir\" install\n}"
+	if !strings.Contains(out, wantBuild) {
+		t.Errorf("generated script does not embed the fixture's build() body verbatim")
+	}
+	if !strings.Contains(out, wantPackage) {
+		t.Errorf("generated script does not embed the fixture's package() body verbatim")
+	}
+}

internal/arch/src/convert.go

@@ -0,0 +1,218 @@
+// Package src converts Arch Linux source packages (PKGBUILD/.SRCINFO) into
+// Zeta recipes.
+package src
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/depmap"
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/registry"
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/zeta"
+)
+
+// Convert converts an Arch source package (a PKGBUILD, a .SRCINFO, or a
+// directory containing either) into a Zeta .recipe with build_system =
+// "custom" plus a generated build.sh, both written into opts.Output:
+//
+//	<out>/<name>.recipe
+//	<out>/build.sh
+//
+// v1 fidelity guardrails error out on shapes Zeta cannot represent yet:
+// split packages, VCS sources (git+/svn+/hg+/bzr+ protocols, <vcs>:: URL
+// fragments, or a dynamic pkgver() function), zero sources and multiple
+// sources. A nonzero epoch and the dropped metadata fields (makedepends,
+// optdepends, provides, conflicts, replaces) are warned about on stderr.
+func Convert(input string, opts registry.Options) error {
+	warn := func(msg string) { fmt.Fprintf(os.Stderr, "warning: %s\n", msg) }
+
+	info, err := Load(input, opts.Arch)
+	if err != nil {
+		return fmt.Errorf("convert: %w", err)
+	}
+	pkgbuildPath, err := resolvePKGBUILD(input)
+	if err != nil {
+		return fmt.Errorf("convert: %w", err)
+	}
+
+	// Fidelity guardrails: v1 covers exactly one package built from exactly
+	// one static tarball source.
+	if len(info.PkgNames) != 1 {
+		return errors.New("convert: split packages not yet supported in v1")
+	}
+	if hasVCS(info, pkgbuildPath) {
+		return errors.New("convert: VCS source not yet supported in v1")
+	}
+	if len(info.Sources) == 0 {
+		return errors.New("convert: no sources not yet supported in v1")
+	}
+	if len(info.Sources) > 1 {
+		return errors.New("convert: multiple sources not yet supported in v1")
+	}
+
+	// Warn-only: an epoch cannot be folded into Zeta versioning, and the
+	// recipe format has no fields for these relations.
+	if info.Epoch != "" && info.Epoch != "0" {
+		warn(fmt.Sprintf("epoch %s is not representable in Zeta versioning", info.Epoch))
+	}
+	for _, f := range []struct {
+		field string
+		vals  []string
+	}{
+		{"makedepends", info.Makedepends},
+		{"optdepends", info.Optdepends},
+		{"provides", info.Provides},
+		{"conflicts", info.Conflicts},
+		{"replaces", info.Replaces},
+	} {
+		if len(f.vals) > 0 {
+			warn(fmt.Sprintf("%s dropped (not representable in Zeta)", f.field))
+		}
+	}
+
+	// Deps: map each declared dependency through the Arch→Zeta name map.
+	// Dropped deps are skipped (MapDep already warned).
+	var deps []string
+	for _, d := range info.Depends {
+		if mapped, ok := depmap.MapDep(d, warn); ok {
+			deps = append(deps, mapped)
+		}
+	}
+
+	summary := info.Desc
+	if summary == "" {
+		// recipe.lua requires a non-empty summary.
+		summary = info.PkgNames[0]
+	}
+
+	recipe := &zeta.Recipe{
+		Name:        info.PkgNames[0],
+		Version:     info.Version,
+		Summary:     summary,
+		URL:         sourceURL(info.Sources[0]),
+		SHA256:      pickSHA256(info.SHA256Sums, warn),
+		Deps:        deps,
+		BuildScript: "build.sh",
+	}
+
+	src, err := recipe.Emit()
+	if err != nil {
+		return fmt.Errorf("convert: emit recipe: %w", err)
+	}
+	if err := os.MkdirAll(opts.Output, 0o755); err != nil {
+		return fmt.Errorf("convert: mkdir %s: %w", opts.Output, err)
+	}
+	recipePath := filepath.Join(opts.Output, recipe.Name+".recipe")
+	if err := os.WriteFile(recipePath, []byte(src), 0o644); err != nil {
+		return fmt.Errorf("convert: write %s: %w", recipePath, err)
+	}
+
+	script, err := Generate(info, pkgbuildPath)
+	if err != nil {
+		return fmt.Errorf("convert: generate build.sh: %w", err)
+	}
+	scriptPath := filepath.Join(opts.Output, "build.sh")
+	if err := os.WriteFile(scriptPath, []byte(script), 0o755); err != nil {
+		return fmt.Errorf("convert: write %s: %w", scriptPath, err)
+	}
+	return nil
+}
+
+// resolvePKGBUILD returns the file whose text feeds Generate and the
+// pkgver() scan: the PKGBUILD when one exists, else the .SRCINFO path (whose
+// content yields no function bodies — stub functions result).
+func resolvePKGBUILD(input string) (string, error) {
+	st, err := os.Stat(input)
+	if err != nil {
+		return "", err
+	}
+	if !st.IsDir() {
+		return input, nil
+	}
+	pkgbuild := filepath.Join(input, "PKGBUILD")
+	if fileExists(pkgbuild) {
+		return pkgbuild, nil
+	}
+	srcinfo := filepath.Join(input, ".SRCINFO")
+	if fileExists(srcinfo) {
+		return srcinfo, nil
+	}
+	return "", fmt.Errorf("src: %s: neither .SRCINFO nor PKGBUILD found", input)
+}
+
+// hasVCS reports whether the source package relies on a VCS source or a
+// dynamic pkgver() function and therefore cannot be represented in v1.
+func hasVCS(info *SrcInfo, pkgbuildPath string) bool {
+	for _, s := range info.Sources {
+		if isVCSSource(s) {
+			return true
+		}
+	}
+	return hasPkgverFunc(pkgbuildPath)
+}
+
+// isVCSSource reports whether a makepkg source entry names a VCS checkout:
+// the git+/svn+/hg+/bzr+ protocol forms or the `<vcs>::<url>` fragment form
+// (e.g. git::https://…). A plain https:// tarball download is a normal
+// source, as is a `name::<url>` entry (a download-name prefix, not a VCS).
+func isVCSSource(s string) bool {
+	for _, prefix := range []string{"git+", "svn+", "hg+", "bzr+"} {
+		if strings.HasPrefix(s, prefix) {
+			return true
+		}
+	}
+	if frag, _, ok := strings.Cut(s, "::"); ok {
+		switch frag {
+		case "git", "svn", "hg", "bzr", "fossil", "cvs", "darcs", "mtn":
+			return true
+		}
+	}
+	return false
+}
+
+// pkgverFuncRE matches a top-level pkgver() function definition in bash
+// (column 0), the makepkg marker for a dynamically computed version.
+var pkgverFuncRE = regexp.MustCompile(`(?m)^pkgver\(`)
+
+func hasPkgverFunc(path string) bool {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return false
+	}
+	return pkgverFuncRE.Match(data)
+}
+
+// sourceURL derives the recipe url from a makepkg source entry: the text
+// after a "name::" prefix when present, otherwise the whole entry verbatim.
+// The URL scheme is never stripped.
+func sourceURL(s string) string {
+	if _, rest, ok := strings.Cut(s, "::"); ok {
+		return rest
+	}
+	return s
+}
+
+// sha256Re matches exactly 64 hex characters, the recipe.lua sha256 shape.
+var sha256Re = regexp.MustCompile(`^[0-9a-fA-F]{64}$`)
+
+// pickSHA256 returns the source sha256 for the recipe, or "" when absent or
+// unusable (an empty value, makepkg's "SKIP" marker, or a non-hex64 string —
+// the latter is warned about because the checksum is dropped).
+func pickSHA256(sums []string, warn func(string)) string {
+	if len(sums) == 0 {
+		return ""
+	}
+	s := strings.TrimSpace(sums[0])
+	if s == "" || strings.EqualFold(s, "SKIP") {
+		return ""
+	}
+	if !sha256Re.MatchString(s) {
+		warn(fmt.Sprintf("sha256sum %q is not 64 hex characters; checksum dropped", s))
+		return ""
+	}
+	return s
+}

internal/arch/src/convert_test.go

@@ -0,0 +1,258 @@
+package src
+
+import (
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/registry"
+)
+
+const (
+	srcinfoDir = "../../../testdata/srcinfo"
+	recipeLua  = "/home/specter/Public/zeta-toolchain/toolchain/lib/?.lua"
+)
+
+// convertMytool runs the full conversion on the mytool fixture directory
+// into a fresh temp dir and returns that dir plus the emitted recipe and
+// build.sh contents.
+func convertMytool(t *testing.T) (out, recipe, script string) {
+	t.Helper()
+	out = t.TempDir()
+	if err := Convert(filepath.Join(srcinfoDir, "mytool"), registry.Options{Output: out}); err != nil {
+		t.Fatalf("Convert(mytool): %v", err)
+	}
+	rb, err := os.ReadFile(filepath.Join(out, "mytool.recipe"))
+	if err != nil {
+		t.Fatalf("mytool.recipe not written: %v", err)
+	}
+	sb, err := os.ReadFile(filepath.Join(out, "build.sh"))
+	if err != nil {
+		t.Fatalf("build.sh not written: %v", err)
+	}
+	return out, string(rb), string(sb)
+}
+
+// convertStderr runs Convert with os.Stderr redirected into a pipe and
+// returns the captured output along with the error. Tests using this helper
+// must not run in parallel.
+func convertStderr(t *testing.T, input string, opts registry.Options) (string, error) {
+	t.Helper()
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("pipe: %v", err)
+	}
+	defer r.Close()
+	old := os.Stderr
+	os.Stderr = w
+	err = Convert(input, opts)
+	if cerr := w.Close(); cerr != nil && err == nil {
+		err = cerr
+	}
+	os.Stderr = old
+	out, rerr := io.ReadAll(r)
+	if rerr != nil {
+		t.Fatalf("read stderr: %v", rerr)
+	}
+	return string(out), err
+}
+
+// quoteLua renders a path as a safe single-quoted Lua string literal.
+func quoteLua(s string) string {
+	return `'` + strings.ReplaceAll(s, `\`, `\\`) + `'`
+}
+
+// writePKGBUILD writes a PKGBUILD fixture into a fresh temp dir and returns
+// the dir (passed as input to Convert).
+func writePKGBUILD(t *testing.T, body string) string {
+	t.Helper()
+	dir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(dir, "PKGBUILD"), []byte(body), 0o644); err != nil {
+		t.Fatalf("write PKGBUILD fixture: %v", err)
+	}
+	return dir
+}
+
+func TestConvert(t *testing.T) {
+	out, recipe, script := convertMytool(t)
+
+	for _, want := range []string{
+		`build_system = "custom"`,
+		`build_script = "build.sh"`,
+		`name         = "mytool"`,
+	} {
+		if !strings.Contains(recipe, want) {
+			t.Errorf("mytool.recipe does not contain %q:\n%s", want, recipe)
+		}
+	}
+	if !strings.Contains(script, `pkgdir="$DESTDIR"`) {
+		t.Errorf("build.sh does not contain pkgdir=\"$DESTDIR\"")
+	}
+
+	if _, err := os.Stat(filepath.Join(out, "mytool.recipe")); err != nil {
+		t.Errorf("mytool.recipe missing: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(out, "build.sh")); err != nil {
+		t.Errorf("build.sh missing: %v", err)
+	}
+}
+
+func TestConvertRecipeLoadsInZeta(t *testing.T) {
+	lua, err := exec.LookPath("lua")
+	if err != nil {
+		t.Skip("lua not available; skipping cross-tool validation")
+	}
+
+	out := t.TempDir()
+	if err := Convert(filepath.Join(srcinfoDir, "mytool"), registry.Options{Output: out}); err != nil {
+		t.Fatalf("Convert(mytool): %v", err)
+	}
+	recipePath := filepath.Join(out, "mytool.recipe")
+
+	probe := `package.path="` + recipeLua + `;"..package.path; ` +
+		`local r,e=require("recipe").load(` + quoteLua(recipePath) + `); assert(r,e)`
+	cmd := exec.Command(lua, "-e", probe)
+	if b, cerr := cmd.CombinedOutput(); cerr != nil {
+		t.Fatalf("real zeta-makepkg recipe.load rejected the emitted recipe: %v\n%s", cerr, b)
+	}
+}
+
+func TestConvertSplitPackage(t *testing.T) {
+	err := Convert(filepath.Join(srcinfoDir, "split"), registry.Options{Output: t.TempDir()})
+	if err == nil {
+		t.Fatal("Convert(split) error = nil, want guardrail error")
+	}
+	if !strings.Contains(err.Error(), "not yet supported") {
+		t.Errorf("Convert(split) error = %q, want it to contain %q", err, "not yet supported")
+	}
+	if !strings.Contains(err.Error(), "split packages not yet supported in v1") {
+		t.Errorf("Convert(split) error = %q, want the split guardrail message", err)
+	}
+}
+
+func TestConvertVCS(t *testing.T) {
+	err := Convert(filepath.Join(srcinfoDir, "vcs"), registry.Options{Output: t.TempDir()})
+	if err == nil {
+		t.Fatal("Convert(vcs) error = nil, want guardrail error")
+	}
+	if !strings.Contains(err.Error(), "not yet supported") {
+		t.Errorf("Convert(vcs) error = %q, want it to contain %q", err, "not yet supported")
+	}
+	if !strings.Contains(err.Error(), "VCS source not yet supported in v1") {
+		t.Errorf("Convert(vcs) error = %q, want the VCS guardrail message", err)
+	}
+}
+
+func TestConvertEpochWarns(t *testing.T) {
+	dir := writePKGBUILD(t, `pkgname=epo
+pkgver=1.0
+pkgrel=1
+epoch=1
+pkgdesc="Epoch fixture"
+arch=(x86_64)
+source=("epo-1.0.tar.gz")
+`)
+	stderr, err := convertStderr(t, dir, registry.Options{Output: t.TempDir()})
+	if err != nil {
+		t.Fatalf("Convert(epoch) error = %v, want nil (epoch warns only)", err)
+	}
+	if !strings.Contains(stderr, "epoch") {
+		t.Errorf("stderr = %q, want a warning mentioning epoch", stderr)
+	}
+}
+
+func TestConvertNamedSourceURL(t *testing.T) {
+	dir := writePKGBUILD(t, `pkgname=namedsrc
+pkgver=1.0
+pkgrel=1
+pkgdesc="Named source fixture"
+arch=(x86_64)
+source=("name::https://example.com/x.tar.gz")
+sha256sums=('SKIP')
+`)
+	out := t.TempDir()
+	if err := Convert(dir, registry.Options{Output: out}); err != nil {
+		t.Fatalf("Convert(named source) error = %v, want nil", err)
+	}
+	content, err := os.ReadFile(filepath.Join(out, "namedsrc.recipe"))
+	if err != nil {
+		t.Fatalf("namedsrc.recipe not written: %v", err)
+	}
+	const wantLine = `url          = "https://example.com/x.tar.gz",`
+	if !strings.Contains(string(content), wantLine) {
+		t.Errorf("recipe url = %q, want the line %q (scheme preserved, name:: stripped):\n%s",
+			string(content), wantLine, content)
+	}
+	if strings.Contains(string(content), "name::") {
+		t.Errorf("recipe still contains the name:: prefix:\n%s", content)
+	}
+}
+
+func TestConvertMissingInput(t *testing.T) {
+	err := Convert(filepath.Join(t.TempDir(), "nope"), registry.Options{Output: t.TempDir()})
+	if err == nil {
+		t.Fatal("Convert(missing) error = nil, want error for nonexistent input")
+	}
+}
+
+func TestConvertZeroSources(t *testing.T) {
+	dir := writePKGBUILD(t, `pkgname=nosrc
+pkgver=1.0
+pkgrel=1
+pkgdesc="No sources fixture"
+arch=(x86_64)
+`)
+	err := Convert(dir, registry.Options{Output: t.TempDir()})
+	if err == nil {
+		t.Fatal("Convert(no sources) error = nil, want guardrail error")
+	}
+	if !strings.Contains(err.Error(), "no sources not yet supported in v1") {
+		t.Errorf("Convert(no sources) error = %q, want the zero-source guardrail message", err)
+	}
+}
+
+func TestConvertMultiSource(t *testing.T) {
+	dir := writePKGBUILD(t, `pkgname=multisrc
+pkgver=1.0
+pkgrel=1
+pkgdesc="Multi source fixture"
+arch=(x86_64)
+source=("a-1.0.tar.gz" "b-1.0.tar.gz")
+sha256sums=('SKIP' 'SKIP')
+`)
+	err := Convert(dir, registry.Options{Output: t.TempDir()})
+	if err == nil {
+		t.Fatal("Convert(multi source) error = nil, want guardrail error")
+	}
+	if !strings.Contains(err.Error(), "multiple sources not yet supported in v1") {
+		t.Errorf("Convert(multi source) error = %q, want the multi-source guardrail message", err)
+	}
+}
+
+func TestConvertDroppedMetadataWarns(t *testing.T) {
+	dir := writePKGBUILD(t, `pkgname=meta
+pkgver=1.0
+pkgrel=1
+pkgdesc="Dropped metadata fixture"
+arch=(x86_64)
+source=("meta-1.0.tar.gz")
+makedepends=('make')
+optdepends=('bonus: optional extra')
+provides=('virt')
+conflicts=('other')
+replaces=('old')
+`)
+	stderr, err := convertStderr(t, dir, registry.Options{Output: t.TempDir()})
+	if err != nil {
+		t.Fatalf("Convert(dropped metadata) error = %v, want nil (warns only)", err)
+	}
+	for _, field := range []string{"makedepends", "optdepends", "provides", "conflicts", "replaces"} {
+		want := "warning: " + field + " dropped (not representable in Zeta)"
+		if !strings.Contains(stderr, want) {
+			t.Errorf("stderr = %q, want warning %q", stderr, want)
+		}
+	}
+}

internal/arch/src/frontend.go

@@ -3,8 +3,6 @@
 package src
 
 import (
-	"errors"
-
 	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/registry"
 )
 
@@ -13,9 +11,9 @@ type frontend struct{}
 
 func (frontend) Name() string { return "arch-src" }
 
+// Convert delegates to the package-level converter (convert.go).
 func (frontend) Convert(input string, opts registry.Options) error {
-	// Implemented in a later todo (PKGBUILD/.SRCINFO -> .recipe + build.sh).
+	return Convert(input, opts)
-	return errors.New("not implemented")
 }
 
 func init() {

internal/arch/src/srcinfo.go

@@ -0,0 +1,299 @@
+package src
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+// ParseSRCINFO parses makepkg .SRCINFO content: lines of "key = value"
+// grouped into a pkgbase section and one or more pkgname sections. Keys in
+// the pkgbase section are inherited by every package; the first pkgname
+// section extends/overrides them (v1 targets single-package recipes, so
+// later pkgname sections only contribute their name to PkgNames — the
+// converter rejects split packages before they get here).
+//
+// Repeatable keys (arch, depends, makedepends, optdepends, provides,
+// conflicts, replaces, source, sha256sums) accumulate; single-value keys
+// (pkgver, pkgrel, epoch, pkgdesc, url) take the last occurrence. Keys
+// suffixed with _<arch> (e.g. depends_x86_64) are folded into their base
+// key only when the suffix matches the requested arch; suffixes for other
+// arches are ignored. An empty arch defaults to x86_64.
+//
+// ParseSRCINFO returns an error when no pkgver is present.
+func ParseSRCINFO(src string, arch string) (*SrcInfo, error) {
+	if arch == "" {
+		arch = "x86_64"
+	}
+	info := &SrcInfo{}
+	pkgnameSections := 0
+	firstSection := true
+	for _, line := range strings.Split(src, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		eq := strings.Index(line, "=")
+		if eq < 0 {
+			continue // malformed line: skip
+		}
+		key := strings.TrimSpace(line[:eq])
+		value := strings.TrimSpace(line[eq+1:])
+		switch key {
+		case "pkgbase":
+			info.PkgBase = value
+		case "pkgname":
+			info.PkgNames = append(info.PkgNames, value)
+			pkgnameSections++
+			firstSection = false
+		default:
+			// Keys in pkgname sections beyond the first are ignored: v1
+			// targets single-package recipes.
+			if !firstSection && pkgnameSections > 1 {
+				continue
+			}
+			if isSingleKey(key) {
+				applyKey(info, key, value)
+				continue
+			}
+			base, ok := foldArchKey(key, arch)
+			if ok {
+				applyKey(info, base, value)
+			}
+			// else: unknown key or a different arch's variant — ignore.
+		}
+	}
+	if info.Version == "" {
+		return nil, errors.New("srcinfo: missing pkgver")
+	}
+	return info, nil
+}
+
+// isSingleKey reports whether key is a single-value (last-wins) .SRCINFO
+// key that never carries an _<arch> suffix.
+func isSingleKey(key string) bool {
+	switch key {
+	case "pkgver", "pkgrel", "epoch", "pkgdesc", "url", "arch":
+		return true
+	}
+	return false
+}
+
+// applyKey records one .SRCINFO key=value into info. Single-value keys take
+// the last occurrence; repeatable keys accumulate.
+func applyKey(info *SrcInfo, key, value string) {
+	switch key {
+	case "pkgver":
+		info.Version = value
+	case "pkgrel":
+		info.Rel = value
+	case "epoch":
+		info.Epoch = value
+	case "pkgdesc":
+		info.Desc = value
+	case "url":
+		info.URL = value
+	case "arch":
+		info.Arch = append(info.Arch, value)
+	case "depends":
+		info.Depends = append(info.Depends, value)
+	case "makedepends":
+		info.Makedepends = append(info.Makedepends, value)
+	case "optdepends":
+		info.Optdepends = append(info.Optdepends, value)
+	case "provides":
+		info.Provides = append(info.Provides, value)
+	case "conflicts":
+		info.Conflicts = append(info.Conflicts, value)
+	case "replaces":
+		info.Replaces = append(info.Replaces, value)
+	case "source":
+		info.Sources = append(info.Sources, value)
+	case "sha256sums":
+		info.SHA256Sums = append(info.SHA256Sums, value)
+	}
+}
+
+// archVariantKeys are the .SRCINFO keys that may carry an _<arch> suffix.
+var archVariantKeys = map[string]bool{
+	"source": true, "depends": true, "makedepends": true, "optdepends": true,
+	"provides": true, "conflicts": true, "replaces": true,
+	"sha256sums": true, "md5sums": true, "sha1sums": true, "sha224sums": true,
+	"sha384sums": true, "sha512sums": true, "b2sums": true,
+}
+
+// foldArchKey maps a .SRCINFO key to the base key it contributes to, and
+// reports whether it applies to the requested arch. A bare key applies to
+// every arch; a `key_<arch>` key applies only when <arch> matches; a
+// `key_<other>` key folds to nothing.
+func foldArchKey(key, arch string) (string, bool) {
+	if base, ok := strings.CutSuffix(key, "_"+arch); ok && archVariantKeys[base] {
+		return base, true
+	}
+	if archVariantKeys[key] {
+		return key, true
+	}
+	if base, _, ok := strings.Cut(key, "_"); ok && archVariantKeys[base] {
+		return "", false
+	}
+	return "", false
+}
+
+// precompiled assignment regexes. PKGBUILDs are bash; these regexes match
+// only top-level `key=value` declarations at column 0, so assignments
+// inside function bodies (indented) and `key() {` function definitions are
+// never evaluated.
+var (
+	reScalar = map[string]*regexp.Regexp{}
+	reArray  = map[string]*regexp.Regexp{}
+)
+
+func init() {
+	for _, key := range []string{"pkgbase", "pkgname", "pkgver", "pkgrel", "epoch", "pkgdesc", "url"} {
+		reScalar[key] = regexp.MustCompile(`(?m)^` + regexp.QuoteMeta(key) + `\s*=\s*(?:'([^']*)'|"([^"]*)"|([^\s'"]+))`)
+	}
+	for _, key := range []string{"pkgname", "arch", "depends", "makedepends", "optdepends", "provides", "conflicts", "replaces", "source", "sha256sums"} {
+		reArray[key] = regexp.MustCompile(`(?ms)^` + regexp.QuoteMeta(key) + `\s*=\s*\(([^)]*)\)`)
+	}
+}
+
+// ParsePKGBUILD best-effort extracts declaration values from a PKGBUILD by
+// regex-matching top-level `key=value` assignments. It NEVER executes bash:
+// function bodies, comments, conditionals and variables are left untouched,
+// and values referencing variables such as $pkgname are kept verbatim.
+// Array assignments (`key=(v1 v2)`, possibly spanning lines) are split on
+// whitespace and unquoted; scalar values may be bare or 'single'/"double"
+// quoted. Unknown constructs are ignored.
+//
+// ParsePKGBUILD returns an error when no usable pkgver declaration is
+// found (pkgver is mandatory in a PKGBUILD).
+func ParsePKGBUILD(src string) (*SrcInfo, error) {
+	info := &SrcInfo{}
+	if v, ok := scalar(src, "pkgbase"); ok {
+		info.PkgBase = v
+	}
+	if names, ok := array(src, "pkgname"); ok {
+		info.PkgNames = names
+	} else if v, ok := scalar(src, "pkgname"); ok {
+		info.PkgNames = []string{v}
+	}
+	info.Version, _ = scalar(src, "pkgver")
+	info.Rel, _ = scalar(src, "pkgrel")
+	info.Epoch, _ = scalar(src, "epoch")
+	info.Desc, _ = scalar(src, "pkgdesc")
+	info.URL, _ = scalar(src, "url")
+	info.Arch, _ = array(src, "arch")
+	info.Depends, _ = array(src, "depends")
+	info.Makedepends, _ = array(src, "makedepends")
+	info.Optdepends, _ = array(src, "optdepends")
+	info.Provides, _ = array(src, "provides")
+	info.Conflicts, _ = array(src, "conflicts")
+	info.Replaces, _ = array(src, "replaces")
+	info.Sources, _ = array(src, "source")
+	info.SHA256Sums, _ = array(src, "sha256sums")
+	if info.Version == "" {
+		return nil, errors.New("pkgbuild: missing pkgver")
+	}
+	return info, nil
+}
+
+// scalar returns the value of a top-level `key=value` scalar assignment.
+// The value may be bare, 'single'- or "double"-quoted. An array assignment
+// is reported as not-found so callers fall back to array().
+func scalar(src, key string) (string, bool) {
+	m := reScalar[key].FindStringSubmatch(src)
+	if m == nil {
+		return "", false
+	}
+	value := m[1]
+	if value == "" {
+		value = m[2]
+	}
+	if value == "" {
+		value = m[3]
+	}
+	value = strings.TrimSpace(value)
+	if strings.HasPrefix(value, "(") {
+		return "", false // array form; caller should use array()
+	}
+	return value, true
+}
+
+// array returns the values of a top-level `key=(v1 v2 ...)` assignment,
+// possibly spanning multiple lines. Tokens are split on whitespace and
+// surrounding single/double quotes are stripped. Best-effort: quoted values
+// containing spaces are not preserved.
+func array(src, key string) ([]string, bool) {
+	m := reArray[key].FindStringSubmatch(src)
+	if m == nil {
+		return nil, false
+	}
+	tokens := strings.Fields(m[1])
+	values := make([]string, 0, len(tokens))
+	for _, tok := range tokens {
+		values = append(values, stripQuotes(tok))
+	}
+	return values, true
+}
+
+// stripQuotes removes a matching pair of surrounding single or double
+// quotes.
+func stripQuotes(s string) string {
+	if len(s) >= 2 {
+		if (s[0] == '\'' && s[len(s)-1] == '\'') || (s[0] == '"' && s[len(s)-1] == '"') {
+			return s[1 : len(s)-1]
+		}
+	}
+	return s
+}
+
+// Load parses the Arch source package at input. If input is a directory it
+// prefers <input>/.SRCINFO and falls back to <input>/PKGBUILD; if input is
+// a file, its basename selects the parser (.SRCINFO or PKGBUILD). Load
+// returns a descriptive error when neither file is found or the file type
+// is unknown.
+func Load(input string, arch string) (*SrcInfo, error) {
+	st, err := os.Stat(input)
+	if err != nil {
+		return nil, fmt.Errorf("src: %s: %w", input, err)
+	}
+	path := input
+	useSRCINFO := false
+	if st.IsDir() {
+		srcinfo := filepath.Join(input, ".SRCINFO")
+		pkgbuild := filepath.Join(input, "PKGBUILD")
+		switch {
+		case fileExists(srcinfo):
+			path, useSRCINFO = srcinfo, true
+		case fileExists(pkgbuild):
+			path = pkgbuild
+		default:
+			return nil, fmt.Errorf("src: %s: neither .SRCINFO nor PKGBUILD found", input)
+		}
+	} else {
+		switch filepath.Base(input) {
+		case ".SRCINFO":
+			useSRCINFO = true
+		case "PKGBUILD":
+		default:
+			return nil, fmt.Errorf("src: %s: unknown source file (want .SRCINFO or PKGBUILD)", input)
+		}
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("src: reading %s: %w", path, err)
+	}
+	if useSRCINFO {
+		return ParseSRCINFO(string(data), arch)
+	}
+	return ParsePKGBUILD(string(data))
+}
+
+// fileExists reports whether path names a regular file.
+func fileExists(path string) bool {
+	st, err := os.Stat(path)
+	return err == nil && !st.IsDir()
+}

internal/arch/src/srcinfo_test.go

@@ -0,0 +1,293 @@
+package src
+
+import (
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+	"testing"
+)
+
+// srcinfoFixtures is the committed testdata tree, relative to this package
+// directory (internal/arch/src).
+const srcinfoFixtures = "../../../testdata/srcinfo"
+
+func readFixture(t *testing.T, path string) string {
+	t.Helper()
+	b, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read fixture %s: %v", path, err)
+	}
+	return string(b)
+}
+
+// TestSrcInfoParseMytoolSRCINFO parses the committed mytool .SRCINFO with
+// arch x86_64 and checks every field the converter consumes.
+func TestSrcInfoParseMytoolSRCINFO(t *testing.T) {
+	src := readFixture(t, filepath.Join(srcinfoFixtures, "mytool", ".SRCINFO"))
+	got, err := ParseSRCINFO(src, "x86_64")
+	if err != nil {
+		t.Fatalf("ParseSRCINFO: %v", err)
+	}
+	if got.PkgBase != "mytool" {
+		t.Errorf("PkgBase = %q, want %q", got.PkgBase, "mytool")
+	}
+	if !slices.Equal(got.PkgNames, []string{"mytool"}) {
+		t.Errorf("PkgNames = %v, want [mytool]", got.PkgNames)
+	}
+	if got.Version != "1.0" || got.Rel != "1" {
+		t.Errorf("Version/Rel = %q/%q, want %q/%q", got.Version, got.Rel, "1.0", "1")
+	}
+	if got.Desc != "Example custom-build package" {
+		t.Errorf("Desc = %q, want %q", got.Desc, "Example custom-build package")
+	}
+	if got.URL != "https://example.org" {
+		t.Errorf("URL = %q, want %q", got.URL, "https://example.org")
+	}
+	if !slices.Equal(got.Arch, []string{"x86_64"}) {
+		t.Errorf("Arch = %v, want [x86_64]", got.Arch)
+	}
+	if !slices.Equal(got.Depends, []string{"glibc"}) {
+		t.Errorf("Depends = %v, want [glibc]", got.Depends)
+	}
+	if !slices.Equal(got.Sources, []string{"mytool-1.0.tar.gz"}) {
+		t.Errorf("Sources = %v, want [mytool-1.0.tar.gz]", got.Sources)
+	}
+	if !slices.Equal(got.SHA256Sums, []string{"SKIP"}) {
+		t.Errorf("SHA256Sums = %v, want [SKIP]", got.SHA256Sums)
+	}
+}
+
+// TestSrcInfoParseMytoolPKGBUILD exercises the best-effort bash fallback on
+// the same package and expects the essential fields to agree.
+func TestSrcInfoParseMytoolPKGBUILD(t *testing.T) {
+	src := readFixture(t, filepath.Join(srcinfoFixtures, "mytool", "PKGBUILD"))
+	got, err := ParsePKGBUILD(src)
+	if err != nil {
+		t.Fatalf("ParsePKGBUILD: %v", err)
+	}
+	if !slices.Equal(got.PkgNames, []string{"mytool"}) {
+		t.Errorf("PkgNames = %v, want [mytool]", got.PkgNames)
+	}
+	if got.Version != "1.0" || got.Rel != "1" {
+		t.Errorf("Version/Rel = %q/%q, want %q/%q", got.Version, got.Rel, "1.0", "1")
+	}
+	if got.Desc != "Example custom-build package" {
+		t.Errorf("Desc = %q, want %q", got.Desc, "Example custom-build package")
+	}
+	if got.URL != "https://example.org" {
+		t.Errorf("URL = %q, want %q", got.URL, "https://example.org")
+	}
+	if !slices.Equal(got.Arch, []string{"x86_64"}) {
+		t.Errorf("Arch = %v, want [x86_64]", got.Arch)
+	}
+	if !slices.Equal(got.Depends, []string{"glibc"}) {
+		t.Errorf("Depends = %v, want [glibc]", got.Depends)
+	}
+	if !slices.Equal(got.Sources, []string{"mytool-1.0.tar.gz"}) {
+		t.Errorf("Sources = %v, want [mytool-1.0.tar.gz]", got.Sources)
+	}
+	if !slices.Equal(got.SHA256Sums, []string{"SKIP"}) {
+		t.Errorf("SHA256Sums = %v, want [SKIP]", got.SHA256Sums)
+	}
+}
+
+// TestSrcInfoParseSplitPKGBUILD: a split package must PARSE fine (rejection
+// happens later in the converter), yielding both pkgnames.
+func TestSrcInfoParseSplitPKGBUILD(t *testing.T) {
+	src := readFixture(t, filepath.Join(srcinfoFixtures, "split", "PKGBUILD"))
+	got, err := ParsePKGBUILD(src)
+	if err != nil {
+		t.Fatalf("ParsePKGBUILD: %v", err)
+	}
+	if !slices.Equal(got.PkgNames, []string{"foo", "bar"}) {
+		t.Errorf("PkgNames = %v, want [foo bar]", got.PkgNames)
+	}
+	if got.PkgBase != "foobar" {
+		t.Errorf("PkgBase = %q, want %q", got.PkgBase, "foobar")
+	}
+	if got.Version != "1.0" {
+		t.Errorf("Version = %q, want %q", got.Version, "1.0")
+	}
+}
+
+// TestSrcInfoParseVCSPKGBUILD: VCS sources must come through verbatim so the
+// converter can detect and reject them with a clear message.
+func TestSrcInfoParseVCSPKGBUILD(t *testing.T) {
+	src := readFixture(t, filepath.Join(srcinfoFixtures, "vcs", "PKGBUILD"))
+	got, err := ParsePKGBUILD(src)
+	if err != nil {
+		t.Fatalf("ParsePKGBUILD: %v", err)
+	}
+	if !slices.Equal(got.PkgNames, []string{"mygit"}) {
+		t.Errorf("PkgNames = %v, want [mygit]", got.PkgNames)
+	}
+	if !slices.Contains(got.Sources, "git+https://example.org/repo.git") {
+		t.Errorf("Sources = %v, want it to contain %q", got.Sources, "git+https://example.org/repo.git")
+	}
+}
+
+// TestSrcInfoArchFilter feeds a .SRCINFO with arch-specific keys and checks
+// that only the requested arch's variants are folded in.
+func TestSrcInfoArchFilter(t *testing.T) {
+	src := `pkgbase = demo
+	pkgver = 2.0
+	pkgrel = 3
+	epoch = 1
+	depends = bash
+	depends_x86_64 = zsh
+	depends_aarch64 = sh
+	source_x86_64 = demo-2.0.tar.gz
+	source_aarch64 = demo-2.0-aarch64.tar.gz
+	sha256sums_x86_64 = SKIP
+	sha256sums_aarch64 = DEADBEEF
+pkgname = demo
+`
+	got, err := ParseSRCINFO(src, "x86_64")
+	if err != nil {
+		t.Fatalf("ParseSRCINFO(x86_64): %v", err)
+	}
+	if !slices.Equal(got.Depends, []string{"bash", "zsh"}) {
+		t.Errorf("Depends(x86_64) = %v, want [bash zsh] (aarch64 variant must NOT leak in)", got.Depends)
+	}
+	if !slices.Equal(got.Sources, []string{"demo-2.0.tar.gz"}) {
+		t.Errorf("Sources(x86_64) = %v, want [demo-2.0.tar.gz]", got.Sources)
+	}
+	if !slices.Equal(got.SHA256Sums, []string{"SKIP"}) {
+		t.Errorf("SHA256Sums(x86_64) = %v, want [SKIP]", got.SHA256Sums)
+	}
+	if got.Version != "2.0" || got.Rel != "3" || got.Epoch != "1" {
+		t.Errorf("Version/Rel/Epoch = %q/%q/%q, want %q/%q/%q", got.Version, got.Rel, got.Epoch, "2.0", "3", "1")
+	}
+
+	got, err = ParseSRCINFO(src, "aarch64")
+	if err != nil {
+		t.Fatalf("ParseSRCINFO(aarch64): %v", err)
+	}
+	if !slices.Equal(got.Depends, []string{"bash", "sh"}) {
+		t.Errorf("Depends(aarch64) = %v, want [bash sh]", got.Depends)
+	}
+	if !slices.Equal(got.Sources, []string{"demo-2.0-aarch64.tar.gz"}) {
+		t.Errorf("Sources(aarch64) = %v, want [demo-2.0-aarch64.tar.gz]", got.Sources)
+	}
+	if !slices.Equal(got.SHA256Sums, []string{"DEADBEEF"}) {
+		t.Errorf("SHA256Sums(aarch64) = %v, want [DEADBEEF]", got.SHA256Sums)
+	}
+}
+
+// TestSrcInfoMultiPkgnameSRCINFO: multiple pkgname sections must not fail
+// parsing; every name is collected, only the FIRST section's keys apply.
+func TestSrcInfoMultiPkgnameSRCINFO(t *testing.T) {
+	src := `pkgbase = split
+	pkgver = 1.0
+	pkgrel = 1
+pkgname = foo
+	depends = a
+pkgname = bar
+	depends = b
+`
+	got, err := ParseSRCINFO(src, "x86_64")
+	if err != nil {
+		t.Fatalf("ParseSRCINFO: %v", err)
+	}
+	if !slices.Equal(got.PkgNames, []string{"foo", "bar"}) {
+		t.Errorf("PkgNames = %v, want [foo bar]", got.PkgNames)
+	}
+	if !slices.Equal(got.Depends, []string{"a"}) {
+		t.Errorf("Depends = %v, want [a] (only the first pkgname section applies)", got.Depends)
+	}
+}
+
+// TestSrcInfoPKGBUILDMissingPkgver: a PKGBUILD without a usable pkgver
+// declaration is malformed and must error.
+func TestSrcInfoPKGBUILDMissingPkgver(t *testing.T) {
+	src := `pkgname=foo
+pkgrel=1
+pkgdesc="no version here"
+arch=(x86_64)
+depends=('glibc')
+`
+	got, err := ParsePKGBUILD(src)
+	if err == nil {
+		t.Fatalf("ParsePKGBUILD = %+v, want error for missing pkgver", got)
+	}
+	if !strings.Contains(err.Error(), "pkgver") {
+		t.Errorf("error %q does not mention pkgver", err)
+	}
+}
+
+// TestSrcInfoLoadDirPrefersSRCINFO: loading a directory uses .SRCINFO first
+// (PkgBase is only present in the .SRCINFO fixture, not the PKGBUILD).
+func TestSrcInfoLoadDirPrefersSRCINFO(t *testing.T) {
+	got, err := Load(filepath.Join(srcinfoFixtures, "mytool"), "x86_64")
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if got.PkgBase != "mytool" {
+		t.Errorf("PkgBase = %q, want %q (proves .SRCINFO was preferred over PKGBUILD)", got.PkgBase, "mytool")
+	}
+	if got.Version != "1.0" {
+		t.Errorf("Version = %q, want %q", got.Version, "1.0")
+	}
+}
+
+// TestSrcInfoLoadDirFallsBackToPKGBUILD: a directory with only a PKGBUILD
+// falls back to the best-effort parser.
+func TestSrcInfoLoadDirFallsBackToPKGBUILD(t *testing.T) {
+	got, err := Load(filepath.Join(srcinfoFixtures, "split"), "x86_64")
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if !slices.Equal(got.PkgNames, []string{"foo", "bar"}) {
+		t.Errorf("PkgNames = %v, want [foo bar]", got.PkgNames)
+	}
+}
+
+// TestSrcInfoLoadFilePKGBUILD: loading a file named PKGBUILD parses it as
+// such regardless of directory.
+func TestSrcInfoLoadFilePKGBUILD(t *testing.T) {
+	got, err := Load(filepath.Join(srcinfoFixtures, "vcs", "PKGBUILD"), "x86_64")
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if !slices.Equal(got.PkgNames, []string{"mygit"}) {
+		t.Errorf("PkgNames = %v, want [mygit]", got.PkgNames)
+	}
+}
+
+// TestSrcInfoLoadFileSRCINFO: loading a file named .SRCINFO parses it as
+// such.
+func TestSrcInfoLoadFileSRCINFO(t *testing.T) {
+	got, err := Load(filepath.Join(srcinfoFixtures, "mytool", ".SRCINFO"), "x86_64")
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if got.PkgBase != "mytool" {
+		t.Errorf("PkgBase = %q, want %q", got.PkgBase, "mytool")
+	}
+}
+
+// TestSrcInfoLoadUnknownFile: a file that is neither .SRCINFO nor PKGBUILD
+// is rejected with a clear error.
+func TestSrcInfoLoadUnknownFile(t *testing.T) {
+	dir := t.TempDir()
+	other := filepath.Join(dir, "notes.txt")
+	if err := os.WriteFile(other, []byte("pkgname=foo\npkgver=1\n"), 0o644); err != nil {
+		t.Fatalf("WriteFile: %v", err)
+	}
+	_, err := Load(other, "x86_64")
+	if err == nil {
+		t.Fatalf("Load(%s) = nil error, want unknown-file error", other)
+	}
+	if !strings.Contains(err.Error(), "unknown") {
+		t.Errorf("error %q does not mention the unknown file type", err)
+	}
+}
+
+// TestSrcInfoLoadMissingDir: a nonexistent path errors clearly.
+func TestSrcInfoLoadMissingDir(t *testing.T) {
+	_, err := Load(filepath.Join(t.TempDir(), "does-not-exist"), "x86_64")
+	if err == nil {
+		t.Fatalf("Load(nonexistent) = nil error, want error")
+	}
+}

internal/depmap/depmap.go

@@ -0,0 +1,537 @@
+// Package depmap maps Arch Linux dependency relations onto Zeta package
+// names.
+//
+// The name tables (zetapkgs, renames, dropped) are checked-in literals so the
+// mapping is hermetic: zetapkgs mirrors the authoritative
+// zeta-packages/packages/index.lua "name = ..." entries.
+package depmap
+
+import (
+	"fmt"
+	"strings"
+)
+
+// MapDep maps a single Arch dependency relation to a Zeta dependency string.
+//
+// Input forms: "name", "name>=1.2", or the optdepend form "name: description".
+// It returns ("", false) when the dependency is dropped (base-system packages
+// Zeta provides outside the package manager). Every drop, rename, and
+// unmapped passthrough fires warn (nil-safe).
+func MapDep(spec string, warn func(string)) (string, bool) {
+	if warn == nil {
+		warn = func(string) {}
+	}
+
+	// 1. Optdepend description form "name: description" — keep the
+	// name+constraint part only.
+	if i := strings.Index(spec, ": "); i >= 0 {
+		spec = spec[:i]
+	}
+
+	// 2. Split the base name from the version constraint. Arch dependency
+	// names never contain the operator characters, so the first one found
+	// starts the constraint.
+	name, constraint := splitConstraint(spec)
+	// Zeta's vercmp.parse_dep accepts "=" but normalizes it to "=="
+	// internally; do the same so emitted specs match Zeta convention.
+	constraint = normalizeConstraint(constraint)
+
+	// 3. Verbatim match against the Zeta package index → passthrough.
+	if _, ok := zetapkgs[name]; ok {
+		return name + constraint, true
+	}
+
+	// 4. Known Arch→Zeta rename (case fixes included) → rename, keep the
+	// constraint.
+	if to, ok := renames[name]; ok {
+		warn(fmt.Sprintf("renamed dependency %q -> %q", name, to))
+		return to + constraint, true
+	}
+
+	// 5. Base-system packages Zeta has no package for → drop.
+	if _, ok := dropped[name]; ok {
+		warn(fmt.Sprintf("dropping base-system dependency %q", name))
+		return "", false
+	}
+
+	// 6. Not in Zeta at all → passthrough loudly.
+	warn(fmt.Sprintf("unmapped dependency %q (passed through)", name+constraint))
+	return name + constraint, true
+}
+
+// splitConstraint returns the base package name and the raw constraint
+// ("", ">=1.2", ...). The split happens at the first operator character
+// ('<', '>', '=', '~'); Arch package names never contain these.
+func splitConstraint(spec string) (name, constraint string) {
+	for i := 0; i < len(spec); i++ {
+		switch spec[i] {
+		case '<', '>', '=', '~':
+			return strings.TrimSpace(spec[:i]), spec[i:]
+		}
+	}
+	return strings.TrimSpace(spec), ""
+}
+
+// normalizeConstraint rewrites a bare "=" operator to "==" (Zeta's canonical
+// form) and leaves every other operator untouched.
+func normalizeConstraint(constraint string) string {
+	trimmed := strings.TrimLeft(constraint, " \t")
+	if strings.HasPrefix(trimmed, "=") && !strings.HasPrefix(trimmed, "==") {
+		return constraint[:len(constraint)-len(trimmed)] + "==" + trimmed[1:]
+	}
+	return constraint
+}
+
+// zetapkgs is the set of every Zeta package name, checked in verbatim from
+// zeta-packages/packages/index.lua ("name = ..." entries).
+var zetapkgs = map[string]struct{}{
+	"a52dec":                    {},
+	"acl":                       {},
+	"adwaita-icon-theme":        {},
+	"adwaita-icon-theme-legacy": {},
+	"alacritty":                 {},
+	"alsa-lib":                  {},
+	"aquamarine":                {},
+	"atkmm":                     {},
+	"at-spi2-core":              {},
+	"avahi":                     {},
+	"bitstreamvera":             {},
+	"brotli":                    {},
+	"btop":                      {},
+	"bubblewrap":                {},
+	"bzip2":                     {},
+	"cairo":                     {},
+	"cairomm":                   {},
+	"caja":                      {},
+	"cava":                      {},
+	"cjson":                     {},
+	"cmatrix":                   {},
+	"composefs":                 {},
+	"cpio":                      {},
+	"ctwm":                      {},
+	"dav1d":                     {},
+	"dbus":                      {},
+	"dbus-glib":                 {},
+	"dejavusans":                {},
+	"discord":                   {},
+	"doas":                      {},
+	"double-conversion":         {},
+	"edelib":                    {},
+	"egl":                       {},
+	"eom":                       {},
+	"exo":                       {},
+	"expat":                     {},
+	"extra-cmake-modules":       {},
+	"faad2":                     {},
+	"fastfetch":                 {},
+	"fd":                        {},
+	"femboysay":                 {},
+	"fftw3":                     {},
+	"file":                      {},
+	"firefox":                   {},
+	"fish":                      {},
+	"flac":                      {},
+	"flatpak":                   {},
+	"fltk":                      {},
+	"fmt":                       {},
+	"fontconfig":                {},
+	"freetype":                  {},
+	"fribidi":                   {},
+	"fvwm3":                     {},
+	"garcon":                    {},
+	"gdk-pixbuf":                {},
+	"git":                       {},
+	"glib":                      {},
+	"glibmm":                    {},
+	"gmp":                       {},
+	"gnupg":                     {},
+	"gnutls":                    {},
+	"gobject-introspection":     {},
+	"gpgme":                     {},
+	"graphene":                  {},
+	"gsettings-desktop-schemas": {},
+	"gtk3":                      {},
+	"gtk4":                      {},
+	"gtk-layer-shell":           {},
+	"gtkmm3":                    {},
+	"gtkmm4":                    {},
+	"gtksourceview4":            {},
+	"gzip":                      {},
+	"harfbuzz":                  {},
+	"hello":                     {},
+	"hicolor-icon-theme":        {},
+	"htop":                      {},
+	"hwdata":                    {},
+	"hyprgraphics":              {},
+	"hyprland":                  {},
+	"hyprlang":                  {},
+	"hyprpaper":                 {},
+	"hyprtoolkit":               {},
+	"hyprutils":                 {},
+	"hyprwayland-scanner":       {},
+	"hyprwire":                  {},
+	"icu":                       {},
+	"imlib2":                    {},
+	"iniparser":                 {},
+	"iso-codes":                 {},
+	"jam":                       {},
+	"json-c":                    {},
+	"jsoncpp":                   {},
+	"kidletime":                 {},
+	"kwindowsystem":             {},
+	"labwc":                     {},
+	"larp":                      {},
+	"layer-shell-qt":            {},
+	"lcms2":                     {},
+	"leancrypto":                {},
+	"less":                      {},
+	"libappstream":              {},
+	"libarchive":                {},
+	"libassuan":                 {},
+	"libb2":                     {},
+	"libcanberra":               {},
+	"libcurl":                   {},
+	"libdaemon":                 {},
+	"libdbusmenu-lxqt":          {},
+	"libdconf":                  {},
+	"libdisplay-info":           {},
+	"libdrm":                    {},
+	"libebml":                   {},
+	"libepoxy":                  {},
+	"libevdev":                  {},
+	"libevent":                  {},
+	"libexif":                   {},
+	"libffi":                    {},
+	"libfm-extra":               {},
+	"libfm-qt":                  {},
+	"libfontenc":                {},
+	"libfuse3":                  {},
+	"libfyaml":                  {},
+	"libgcrypt":                 {},
+	"libglvnd":                  {},
+	"libgpg-error":              {},
+	"libgtop":                   {},
+	"libgudev":                  {},
+	"libICE":                    {},
+	"libidn2":                   {},
+	"libinput":                  {},
+	"libjpeg-turbo":             {},
+	"libjson-glib":              {},
+	"libksba":                   {},
+	"liblxqt":                   {},
+	"libmatekbd":                {},
+	"libmateweather":            {},
+	"libmatroska":               {},
+	"libmtdev":                  {},
+	"libnl":                     {},
+	"libnotify":                 {},
+	"libogg":                    {},
+	"libostree":                 {},
+	"libpciaccess":              {},
+	"libpeas":                   {},
+	"libpng":                    {},
+	"libpsl":                    {},
+	"libqtxdg":                  {},
+	"libreoffice":               {},
+	"libreoffice-core":          {},
+	"libreoffice-help":          {},
+	"libreoffice-share":         {},
+	"librsvg":                   {},
+	"libseccomp":                {},
+	"libshout":                  {},
+	"libsigc++":                 {},
+	"libsigc++2":                {},
+	"libSM":                     {},
+	"libsndfile":                {},
+	"libsoup2":                  {},
+	"libsoup3":                  {},
+	"libtasn1":                  {},
+	"libtdb":                    {},
+	"libtheora":                 {},
+	"libtinfo":                  {},
+	"libtirpc":                  {},
+	"libudev":                   {},
+	"libunistring":              {},
+	"libuuid":                   {},
+	"libva":                     {},
+	"libvorbis":                 {},
+	"libvpx":                    {},
+	"libwacom":                  {},
+	"libwebp":                   {},
+	"libwnck3":                  {},
+	"libX11":                    {},
+	"libXau":                    {},
+	"libXaw":                    {},
+	"libxcb":                    {},
+	"libxcb-xrm":                {},
+	"libXcomposite":             {},
+	"libXcursor":                {},
+	"libxcvt":                   {},
+	"libXdamage":                {},
+	"libXdmcp":                  {},
+	"libXext":                   {},
+	"libxfce4ui":                {},
+	"libxfce4util":              {},
+	"libxfce4windowing":         {},
+	"libXfixes":                 {},
+	"libXfont2":                 {},
+	"libXft":                    {},
+	"libXi":                     {},
+	"libXinerama":               {},
+	"libXkbfile":                {},
+	"libxklavier":               {},
+	"libxml2":                   {},
+	"libxmlb":                   {},
+	"libXmu":                    {},
+	"libXpm":                    {},
+	"libXpresent":               {},
+	"libXrandr":                 {},
+	"libXrender":                {},
+	"libXres":                   {},
+	"libxshmfence":              {},
+	"libxss":                    {},
+	"libXt":                     {},
+	"libXtst":                   {},
+	"libXvMC":                   {},
+	"libXxf86vm":                {},
+	"libyaml":                   {},
+	"libz":                      {},
+	"lm-sensors":                {},
+	"lua51":                     {},
+	"luajit":                    {},
+	"luv":                       {},
+	"lxqt":                      {},
+	"lxqt-about":                {},
+	"lxqt-build-tools":          {},
+	"lxqt-config":               {},
+	"lxqt-globalkeys":           {},
+	"lxqt-menu-data":            {},
+	"lxqt-notificationd":        {},
+	"lxqt-panel":                {},
+	"lxqt-policykit":            {},
+	"lxqt-powermanagement":      {},
+	"lxqt-qtplugin":             {},
+	"lxqt-runner":               {},
+	"lxqt-session":              {},
+	"lxqt-themes":               {},
+	"lz4":                       {},
+	"make":                      {},
+	"mango":                     {},
+	"marco":                     {},
+	"mate":                      {},
+	"mate-backgrounds":          {},
+	"mate-calc":                 {},
+	"mate-control-center":       {},
+	"mate-desktop":              {},
+	"mate-icon-theme":           {},
+	"mate-menus":                {},
+	"mate-notification-daemon":  {},
+	"mate-panel":                {},
+	"mate-polkit":               {},
+	"mate-power-manager":        {},
+	"mate-session-manager":      {},
+	"mate-settings-daemon":      {},
+	"mate-terminal":             {},
+	"mate-utils":                {},
+	"md4c":                      {},
+	"menu-cache":                {},
+	"mesa":                      {},
+	"mesa-dri-gallium":          {},
+	"mesa-gl":                   {},
+	"micro":                     {},
+	"mksh":                      {},
+	"mm-common":                 {},
+	"mpc":                       {},
+	"mpfr":                      {},
+	"mpg123":                    {},
+	"muparser":                  {},
+	"neovim":                    {},
+	"nettle":                    {},
+	"nghttp2":                   {},
+	"npth":                      {},
+	"nscde":                     {},
+	"nss":                       {},
+	"ntbtls":                    {},
+	"nvidia":                    {},
+	"nvidia-compiler":           {},
+	"nvidia-cuda":               {},
+	"nvidia-firmware":           {},
+	"nvidia-kernel":             {},
+	"nvidia-optix":              {},
+	"nvidia-utils":              {},
+	"openbox":                   {},
+	"opencode":                  {},
+	"openssl":                   {},
+	"opsec":                     {},
+	"opus":                      {},
+	"p11-kit":                   {},
+	"pango":                     {},
+	"pangomm":                   {},
+	"pcmanfm-qt":                {},
+	"pcre2":                     {},
+	"pekwm":                     {},
+	"pinentry":                  {},
+	"pipewire":                  {},
+	"pixman":                    {},
+	"plasma-wayland-protocols":  {},
+	"pluma":                     {},
+	"polkit":                    {},
+	"polkit-qt-1":               {},
+	"procps-ng":                 {},
+	"pugixml":                   {},
+	"pulseaudio":                {},
+	"qt5":                       {},
+	"qtbase":                    {},
+	"qtdeclarative":             {},
+	"qterminal":                 {},
+	"qtermwidget":               {},
+	"qtshadertools":             {},
+	"qtsvg":                     {},
+	"qttools":                   {},
+	"qtwayland":                 {},
+	"ripgrep":                   {},
+	"rofi":                      {},
+	"rsync":                     {},
+	"scenefx":                   {},
+	"sdl2":                      {},
+	"seatd":                     {},
+	"setxkbmap":                 {},
+	"shared-mime-info":          {},
+	"solid":                     {},
+	"spdlog":                    {},
+	"speex":                     {},
+	"spirv-tools":               {},
+	"sqlite":                    {},
+	"startup-notification":      {},
+	"swaybg":                    {},
+	"taglib":                    {},
+	"tango-icon-theme":          {},
+	"tar":                       {},
+	"thunar":                    {},
+	"tllist":                    {},
+	"tree":                      {},
+	"tree-sitter":               {},
+	"tslib":                     {},
+	"twolame":                   {},
+	"unibilium":                 {},
+	"unzip":                     {},
+	"upower":                    {},
+	"util-macros":               {},
+	"vim":                       {},
+	"vlc":                       {},
+	"vte":                       {},
+	"vulkan-headers":            {},
+	"waybar":                    {},
+	"wayland":                   {},
+	"wayland-protocols":         {},
+	"wget":                      {},
+	"which":                     {},
+	"wlroots":                   {},
+	"wlr-protocols":             {},
+	"wmaker":                    {},
+	"wofi":                      {},
+	"xauth":                     {},
+	"xcb-proto":                 {},
+	"xcb-util":                  {},
+	"xcb-util-cursor":           {},
+	"xcb-util-image":            {},
+	"xcb-util-keysyms":          {},
+	"xcb-util-renderutil":       {},
+	"xcb-util-wm":               {},
+	"xdg-desktop-portal":        {},
+	"xdg-user-dirs":             {},
+	"xdpyinfo":                  {},
+	"xf86-input-libinput":       {},
+	"xf86-video-intel":          {},
+	"xfce4":                     {},
+	"xfce4-appfinder":           {},
+	"xfce4-dev-tools":           {},
+	"xfce4-notifyd":             {},
+	"xfce4-panel":               {},
+	"xfce4-power-manager":       {},
+	"xfce4-session":             {},
+	"xfce4-settings":            {},
+	"xfce4-terminal":            {},
+	"xfconf":                    {},
+	"xfdesktop":                 {},
+	"xfwm4":                     {},
+	"xgamma":                    {},
+	"xinit":                     {},
+	"xkbcommon":                 {},
+	"xkbcomp":                   {},
+	"xkeyboard-config":          {},
+	"xmessage":                  {},
+	"xmodmap":                   {},
+	"xorg-full":                 {},
+	"xorgproto":                 {},
+	"xorg-server":               {},
+	"xprop":                     {},
+	"xrandr":                    {},
+	"xrdb":                      {},
+	"xset":                      {},
+	"xshmfence":                 {},
+	"xterm":                     {},
+	"xtrans":                    {},
+	"xwayland":                  {},
+	"xz-utils":                  {},
+	"zip":                       {},
+	"zsh":                       {},
+	"zstd":                      {},
+}
+
+// renames maps Arch Linux package names to their Zeta counterparts. Sources
+// are Arch's canonical (lowercase) spelling; targets are the verbatim names
+// in zetapkgs. The libX* entries are pure case fixes (Arch spells the X11
+// family lowercase); libxcb and friends are already correct in Zeta and
+// deliberately absent.
+var renames = map[string]string{
+	"zlib":          "libz",
+	"xz":            "xz-utils",
+	"freetype2":     "freetype",
+	"libxkbcommon":  "xkbcommon",
+	"libice":        "libICE",
+	"libsm":         "libSM",
+	"libx11":        "libX11",
+	"libxau":        "libXau",
+	"libxaw":        "libXaw",
+	"libxcomposite": "libXcomposite",
+	"libxcursor":    "libXcursor",
+	"libxdamage":    "libXdamage",
+	"libxdmcp":      "libXdmcp",
+	"libxext":       "libXext",
+	"libxfixes":     "libXfixes",
+	"libxfont2":     "libXfont2",
+	"libxft":        "libXft",
+	"libxi":         "libXi",
+	"libxinerama":   "libXinerama",
+	"libxkbfile":    "libXkbfile",
+	"libxmu":        "libXmu",
+	"libxpm":        "libXpm",
+	"libxpresent":   "libXpresent",
+	"libxrandr":     "libXrandr",
+	"libxrender":    "libXrender",
+	"libxres":       "libXres",
+	"libxt":         "libXt",
+	"libxtst":       "libXtst",
+	"libxvmc":       "libXvMC",
+	"libxxf86vm":    "libXxf86vm",
+}
+
+// dropped lists Arch base-system packages that Zeta provides outside the
+// package manager and therefore has no package for (mirroring the dbus and
+// libudev stubs in the index).
+var dropped = map[string]struct{}{
+	"glibc":             {},
+	"gcc-libs":          {},
+	"gcc":               {},
+	"bash":              {},
+	"coreutils":         {},
+	"filesystem":        {},
+	"linux-api-headers": {},
+	"systemd":           {},
+	"util-linux":        {},
+	"ncurses":           {},
+	"readline":          {},
+	"tzdata":            {},
+	"ca-certificates":   {},
+}

internal/depmap/depmap_test.go

@@ -0,0 +1,202 @@
+package depmap
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestMapDep(t *testing.T) {
+	tests := []struct {
+		name    string
+		spec    string
+		want    string
+		wantOK  bool
+		warns   int
+		warnMsg string // exact expected warn message ("" = only check count)
+	}{
+		{
+			name:   "zlib renames to libz",
+			spec:   "zlib",
+			want:   "libz",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:    "glibc dropped as base system",
+			spec:    "glibc",
+			want:    "",
+			wantOK:  false,
+			warns:   1,
+			warnMsg: `dropping base-system dependency "glibc"`,
+		},
+		{
+			name:   "verbatim index name keeps constraint",
+			spec:   "pcre2>=10.42",
+			want:   "pcre2>=10.42",
+			wantOK: true,
+			warns:  0,
+		},
+		{
+			name:   "optdepend description stripped",
+			spec:   "python: for scripting",
+			want:   "python",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:    "unknown dep passes through with warn",
+			spec:    "someunknownpkg123",
+			want:    "someunknownpkg123",
+			wantOK:  true,
+			warns:   1,
+			warnMsg: `unmapped dependency "someunknownpkg123" (passed through)`,
+		},
+		{
+			name:   "rename preserves constraint",
+			spec:   "zlib>=1.3.1",
+			want:   "libz>=1.3.1",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:   "x11 case fix libx11",
+			spec:   "libx11",
+			want:   "libX11",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:   "xz renames to xz-utils",
+			spec:   "xz",
+			want:   "xz-utils",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:   "x11 case fix libice",
+			spec:   "libice",
+			want:   "libICE",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:   "freetype2 renames to freetype",
+			spec:   "freetype2",
+			want:   "freetype",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:   "libxkbcommon renames to xkbcommon",
+			spec:   "libxkbcommon",
+			want:   "xkbcommon",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:   "libxcb already correct not renamed",
+			spec:   "libxcb",
+			want:   "libxcb",
+			wantOK: true,
+			warns:  0,
+		},
+		{
+			name:   "zeta casing input passes through verbatim",
+			spec:   "libX11",
+			want:   "libX11",
+			wantOK: true,
+			warns:  0,
+		},
+		{
+			name:   "bare = normalized to ==",
+			spec:   "foo=1.0",
+			want:   "foo==1.0",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:   "description plus constraint plus rename",
+			spec:   "zlib>=1.2: for compression",
+			want:   "libz>=1.2",
+			wantOK: true,
+			warns:  1,
+		},
+		{
+			name:   "drop applies regardless of constraint",
+			spec:   "glibc>=2.38",
+			want:   "",
+			wantOK: false,
+			warns:  1,
+		},
+		{
+			name:   "gcc-libs dropped",
+			spec:   "gcc-libs",
+			want:   "",
+			wantOK: false,
+			warns:  1,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var warns []string
+			got, ok := MapDep(tt.spec, func(msg string) {
+				warns = append(warns, msg)
+			})
+
+			if got != tt.want {
+				t.Errorf("MapDep(%q) = %q, want %q", tt.spec, got, tt.want)
+			}
+			if ok != tt.wantOK {
+				t.Errorf("MapDep(%q) ok = %v, want %v", tt.spec, ok, tt.wantOK)
+			}
+			if len(warns) != tt.warns {
+				t.Errorf("MapDep(%q) fired %d warns (%v), want %d",
+					tt.spec, len(warns), warns, tt.warns)
+			}
+			if tt.warnMsg != "" && len(warns) == 1 && warns[0] != tt.warnMsg {
+				t.Errorf("MapDep(%q) warn = %q, want %q", tt.spec, warns[0], tt.warnMsg)
+			}
+		})
+	}
+}
+
+// TestMapDepNilWarn ensures MapDep tolerates a nil warn callback.
+func TestMapDepNilWarn(t *testing.T) {
+	got, ok := MapDep("zlib", nil)
+	if got != "libz" || !ok {
+		t.Fatalf("MapDep(zlib, nil) = %q, %v; want %q, true", got, ok, "libz")
+	}
+}
+
+// TestRenameTargetsExistInIndex guards the checked-in tables against typos:
+// every rename target must be a real Zeta package, and every dropped name must
+// NOT be one.
+func TestRenameTargetsExistInIndex(t *testing.T) {
+	for from, to := range renames {
+		if _, ok := zetapkgs[to]; !ok {
+			t.Errorf("rename %q -> %q: target not in zetapkgs index", from, to)
+		}
+		if _, ok := zetapkgs[from]; ok {
+			t.Errorf("rename %q -> %q: source already in zetapkgs (rename is dead code)", from, to)
+		}
+		if _, ok := dropped[to]; ok {
+			t.Errorf("rename %q -> %q: target also in drop list", from, to)
+		}
+	}
+	for name := range dropped {
+		if _, ok := zetapkgs[name]; ok {
+			t.Errorf("drop %q: present in zetapkgs index (drop is wrong)", name)
+		}
+	}
+}
+
+// TestRenamesSortedLint is a cheap self-check that rename sources are
+// lowercase (Arch convention) so case fixes are keyed from the Arch spelling.
+func TestRenamesLowercaseKeys(t *testing.T) {
+	for from := range renames {
+		if strings.ToLower(from) != from {
+			t.Errorf("rename key %q is not lowercase", from)
+		}
+	}
+}

internal/e2e/e2e_test.go

@@ -0,0 +1,135 @@
+// Package e2e cross-validates the emitted Zeta artifacts against the REAL
+// Zeta Lua loaders: the arch-binary package.lua through ZETA/lib/manifest.lua
+// and the arch-src .recipe through zeta-toolchain/toolchain/lib/recipe.lua.
+//
+// The converters are driven as packages (not via the CLI), so this runs
+// under plain `go test` with no built binary. Everything lands in
+// t.TempDir(); the only absolute paths are the two loader library roots,
+// which live in sibling repositories and cannot be expressed relative to
+// this module.
+package e2e
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/arch/binary"
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/arch/src"
+	"git.spectoria.dev/huntedbytheirs/zeta-reconstruct/internal/registry"
+)
+
+const (
+	// manifestLibRoot lets a Lua probe require("manifest") from the ZETA
+	// library checkout.
+	manifestLibRoot = "/home/specter/Public/ZETA/lib/?.lua"
+	// recipeLibRoot lets a Lua probe require("recipe") from the
+	// zeta-toolchain library checkout.
+	recipeLibRoot = "/home/specter/Public/zeta-toolchain/toolchain/lib/?.lua"
+)
+
+// runLua executes script with the `lua` interpreter and returns its output.
+// The whole suite is skipped when lua is not installed.
+func runLua(t *testing.T, script string) (string, error) {
+	t.Helper()
+	lua, err := exec.LookPath("lua")
+	if err != nil {
+		t.Skipf("lua not installed: %v", err)
+	}
+	out, err := exec.Command(lua, "-e", script).Output()
+	return string(out), err
+}
+
+// manifestProbe returns a Lua script that loads the manifest at path through
+// the real ZETA manifest.load. assert makes a nil,nil-err result a hard
+// failure (non-zero exit), so exit code 0 proves load+normalize succeeded.
+// The trailing ";" separates our component from the default package.path.
+func manifestProbe(path string) string {
+	return fmt.Sprintf(
+		`package.path=%q..package.path; local m=require("manifest"); assert(m.load(%q))`,
+		manifestLibRoot+";", path,
+	)
+}
+
+// recipeProbe returns a Lua script that loads the recipe at path through the
+// real zeta-makepkg recipe.load, with the same assert semantics.
+func recipeProbe(path string) string {
+	return fmt.Sprintf(
+		`package.path=%q..package.path; local r=require("recipe"); assert(r.load(%q))`,
+		recipeLibRoot+";", path,
+	)
+}
+
+// TestEndToEnd runs both converters into one temp dir and validates every
+// emitted artifact through the real Lua loaders.
+func TestEndToEnd(t *testing.T) {
+	out := t.TempDir()
+
+	// arch-binary: committed fixture -> packages/hello/package.lua.
+	if err := binary.Convert(
+		filepath.Join("..", "..", "testdata", "hello-1.0-1-x86_64.pkg.tar.zst"),
+		registry.Options{Output: out, Repo: "https://example.org/repo"},
+	); err != nil {
+		t.Fatalf("binary.Convert: %v", err)
+	}
+	manifestPath := filepath.Join(out, "packages", "hello", "package.lua")
+	if _, err := os.Stat(manifestPath); err != nil {
+		t.Fatalf("expected manifest at %s: %v", manifestPath, err)
+	}
+	if stdout, err := runLua(t, manifestProbe(manifestPath)); err != nil {
+		t.Fatalf("manifest probe failed: %v\nlua output: %s", err, stdout)
+	}
+
+	// arch-src: committed fixture -> <out>/mytool.recipe.
+	if err := src.Convert(
+		filepath.Join("..", "..", "testdata", "srcinfo", "mytool"),
+		registry.Options{Output: out, Arch: "x86_64"},
+	); err != nil {
+		t.Fatalf("src.Convert: %v", err)
+	}
+	recipePath := filepath.Join(out, "mytool.recipe")
+	if _, err := os.Stat(recipePath); err != nil {
+		t.Fatalf("expected recipe at %s: %v", recipePath, err)
+	}
+	if stdout, err := runLua(t, recipeProbe(recipePath)); err != nil {
+		t.Fatalf("recipe probe failed: %v\nlua output: %s", err, stdout)
+	}
+}
+
+// TestEndToEndRejectsBrokenManifest proves the manifest probe is real, not a
+// no-op: corrupting the emitted sha256 must make manifest.load (and thus the
+// probe) fail. A probe that ignored the file would let this test fail.
+func TestEndToEndRejectsBrokenManifest(t *testing.T) {
+	out := t.TempDir()
+
+	if err := binary.Convert(
+		filepath.Join("..", "..", "testdata", "hello-1.0-1-x86_64.pkg.tar.zst"),
+		registry.Options{Output: out, Repo: "https://example.org/repo"},
+	); err != nil {
+		t.Fatalf("binary.Convert: %v", err)
+	}
+	manifestPath := filepath.Join(out, "packages", "hello", "package.lua")
+	content, err := os.ReadFile(manifestPath)
+	if err != nil {
+		t.Fatalf("read manifest: %v", err)
+	}
+
+	sha256Re := regexp.MustCompile(`[0-9a-fA-F]{64}`)
+	broken := sha256Re.ReplaceAllString(string(content), "zzz")
+	if broken == string(content) || !strings.Contains(broken, "zzz") {
+		t.Fatal("could not corrupt the manifest: no 64-hex sha256 found")
+	}
+	brokenPath := filepath.Join(out, "broken-package.lua")
+	if err := os.WriteFile(brokenPath, []byte(broken), 0o644); err != nil {
+		t.Fatalf("write broken manifest: %v", err)
+	}
+
+	stdout, err := runLua(t, manifestProbe(brokenPath))
+	if err == nil {
+		t.Fatalf("probe unexpectedly accepted broken manifest\nlua output: %s", stdout)
+	}
+}

internal/zeta/manifest.go

@@ -0,0 +1,251 @@
+// Package zeta models the Zeta package formats (package.lua manifests and
+// .recipe files) and emits them byte-for-byte the way the Zeta toolchain does.
+//
+// The Manifest here covers archive mode only (v1 of zeta-reconstruct emits
+// only archive-mode package.lua); install/build strategies are out of scope.
+package zeta
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+// Manifest is the Go model of a Zeta package.lua manifest (archive mode).
+//
+// Arch and Files mirror Zeta's KNOWN_KEYS (ZETA/lib/manifest.lua) and are kept
+// for forward compatibility; they are not populated in v1 and never emitted.
+// Archive is the (v1-only) install strategy: `archive = { strip = N }`.
+type Manifest struct {
+	Name    string
+	Version string
+	Summary string
+	URL     string
+	SHA256  string
+	Arch    string
+	Deps    []string
+	Files   []string
+	Archive *Archive
+}
+
+// Archive declares the tarball strip level, mirroring Zeta's
+// `archive = { strip = N }` install strategy.
+type Archive struct {
+	Strip int
+}
+
+var (
+	// nameRe mirrors ZETA/lib/path.lua sanitize_name's character class
+	// ([%w%._+%-]+, i.e. [A-Za-z0-9_.+-]).
+	nameRe = regexp.MustCompile(`^[A-Za-z0-9_.+-]+$`)
+
+	// sha256Re mirrors manifest.lua's HEX64: ^ + 64 × %x + $.
+	sha256Re = regexp.MustCompile(`^[0-9a-f]{64}$`)
+
+	// httpRe mirrors manifest.lua's `^https?://` remote-URL test.
+	httpRe = regexp.MustCompile(`^https?://`)
+
+	// unsafeURLRe mirrors manifest.lua's local-URL safety test: a URL that is
+	// not http(s) may not contain whitespace or backslashes.
+	unsafeURLRe = regexp.MustCompile(`[\s\\]`)
+
+	// depSpecRe mirrors vercmp.lua parse_dep's first step:
+	// leading whitespace, a name of [%w%._%+%-]+ characters, whitespace, and
+	// the rest of the spec (constraint or empty).
+	depSpecRe = regexp.MustCompile(`^\s*([A-Za-z0-9_.+-]+)\s*(.*)$`)
+
+	// depOpRe and depVerRe mirror parse_dep's operator/version extraction.
+	depOpRe  = regexp.MustCompile(`^([<>=~]+)\s*`)
+	depVerRe = regexp.MustCompile(`^[<>=~]+\s*([A-Za-z0-9_.+-]+)\s*$`)
+
+	// validDepOps mirrors ZETA/lib/vercmp.lua's OPS table.
+	validDepOps = map[string]bool{
+		">=": true, "<=": true, "==": true, "~=": true,
+		">": true, "<": true, "=": true,
+	}
+
+	// cleanReDotSlash/cleanReLeadSlash/cleanReTrailSlash mirror the three
+	// anchored gsubs of manifest.lua's clean_rel, in the same order.
+	cleanReDotSlash   = regexp.MustCompile(`^\./+`)
+	cleanReLeadSlash  = regexp.MustCompile(`^/+`)
+	cleanReTrailSlash = regexp.MustCompile(`/+$`)
+)
+
+// validName mirrors ZETA/lib/path.lua sanitize_name: non-empty, no leading
+// dot, and every character in [A-Za-z0-9_.+-].
+func validName(name string) bool {
+	if name == "" || strings.HasPrefix(name, ".") {
+		return false
+	}
+	return nameRe.MatchString(name)
+}
+
+// cleanRel mirrors manifest.lua's clean_rel: strip a "./" prefix, a "/"
+// prefix, and a "/" suffix (in that order), producing the canonical
+// root-relative form.
+func cleanRel(p string) string {
+	p = cleanReDotSlash.ReplaceAllString(p, "")
+	p = cleanReLeadSlash.ReplaceAllString(p, "")
+	p = cleanReTrailSlash.ReplaceAllString(p, "")
+	return p
+}
+
+// relativeInside mirrors ZETA/lib/path.lua relative_inside: true if the
+// relative path never climbs above its root via ".." segments.
+func relativeInside(p string) bool {
+	depth := 0
+	for _, seg := range strings.Split(p, "/") {
+		switch seg {
+		case "..":
+			depth--
+			if depth < 0 {
+				return false
+			}
+		case ".", "":
+			// "." and empty segments (from "//") neither climb nor descend.
+		default:
+			depth++
+		}
+	}
+	return true
+}
+
+// escape mirrors packager.lua's escape: quote backslash-quoting first, then
+// newline escaping, in the same order as the Lua gsub chain.
+func escape(s string) string {
+	s = strings.ReplaceAll(s, `"`, `\"`)
+	s = strings.ReplaceAll(s, "\n", `\n`)
+	return s
+}
+
+// parseDep mirrors ZETA/lib/vercmp.lua parse_dep:
+// "pcre2>=10.42" -> ("pcre2", ">=", "10.42"), "libffi" -> ("libffi", "", "").
+// A bare "=" operator is normalized to "==", as in vercmp.lua.
+func parseDep(spec string) (name, op, version string, err error) {
+	sm := depSpecRe.FindStringSubmatch(spec)
+	if sm == nil {
+		return "", "", "", fmt.Errorf("bad dependency %q", spec)
+	}
+	name, rest := sm[1], sm[2]
+	if rest == "" {
+		return name, "", "", nil
+	}
+	om := depOpRe.FindStringSubmatch(rest)
+	vm := depVerRe.FindStringSubmatch(rest)
+	if om == nil || vm == nil || !validDepOps[om[1]] {
+		return "", "", "", fmt.Errorf("bad dependency constraint %q (expected NAME OP VERSION)", spec)
+	}
+	op = om[1]
+	version = vm[1]
+	if op == "=" {
+		op = "=="
+	}
+	return name, op, version, nil
+}
+
+// Validate checks the manifest against Zeta's own rules, mirroring
+// ZETA/lib/manifest.lua normalize exactly (archive path only):
+//
+//  1. name: non-empty, no leading dot, all of [A-Za-z0-9_.+-]
+//  2. version: non-empty
+//  3. sha256: when set, exactly 64 hex characters (uppercase accepted and
+//     normalized to lowercase, as manifest.lua does)
+//  4. url: non-http(s) URLs must not contain whitespace or backslashes
+//  5. deps: each entry must parse as NAME [OP VERSION] with a known operator,
+//     and must not depend on the package itself
+//  6. files: entries must be non-empty, clean to a path that stays inside the
+//     install root, and appear only once
+//  7. archive.strip: non-negative integer
+//  8. archive mode requires a url (v1 is archive-only, so url is always
+//     required)
+//  9. remote http(s) urls must declare sha256
+func (m *Manifest) Validate() error {
+	if !validName(m.Name) {
+		return fmt.Errorf("manifest: missing or invalid package name")
+	}
+	if m.Version == "" {
+		return fmt.Errorf("manifest: package %q missing version", m.Name)
+	}
+
+	if m.SHA256 != "" {
+		lower := strings.ToLower(m.SHA256)
+		if !sha256Re.MatchString(lower) {
+			return fmt.Errorf("manifest: package %q sha256 must be exactly 64 hex characters", m.Name)
+		}
+		m.SHA256 = lower
+	}
+
+	if m.URL != "" && !httpRe.MatchString(m.URL) && unsafeURLRe.MatchString(m.URL) {
+		return fmt.Errorf("manifest: package %q url %q looks unsafe", m.Name, m.URL)
+	}
+
+	for _, d := range m.Deps {
+		depName, _, _, err := parseDep(d)
+		if err != nil {
+			return fmt.Errorf("manifest: package %q: %w", m.Name, err)
+		}
+		if depName == m.Name {
+			return fmt.Errorf("manifest: package %q depends on itself", m.Name)
+		}
+	}
+
+	seen := make(map[string]bool, len(m.Files))
+	for _, f := range m.Files {
+		if f == "" {
+			return fmt.Errorf("manifest: package %q has an empty files entry", m.Name)
+		}
+		rel := cleanRel(f)
+		if rel == "" || !relativeInside(rel) {
+			return fmt.Errorf("manifest: package %q files entry %q escapes the root", m.Name, f)
+		}
+		if seen[rel] {
+			return fmt.Errorf("manifest: package %q lists %q twice in files", m.Name, rel)
+		}
+		seen[rel] = true
+	}
+
+	if m.Archive != nil && m.Archive.Strip < 0 {
+		return fmt.Errorf("manifest: package %q archive.strip must be a non-negative integer", m.Name)
+	}
+
+	if m.URL == "" {
+		return fmt.Errorf("manifest: package %q archive mode requires a url", m.Name)
+	}
+	if httpRe.MatchString(m.URL) && m.SHA256 == "" {
+		return fmt.Errorf("manifest: package %q must declare sha256 for a remote url", m.Name)
+	}
+
+	return nil
+}
+
+// Emit renders the archive-mode package.lua with the exact byte format of
+// packager.lua's write_manifest: 2-space indent, "="-aligned field names in
+// the order name/version/summary/url/sha256/deps/archive, `archive = { strip = 1 }`,
+// and no test function. Summary and deps values are escaped (quote/newline);
+// name/version/url/sha256 are emitted raw (they are validated-safe). Emit
+// fails if the manifest does not Validate.
+func (m *Manifest) Emit() (string, error) {
+	if err := m.Validate(); err != nil {
+		return "", err
+	}
+
+	var b strings.Builder
+	b.WriteString("return {\n")
+	b.WriteString(fmt.Sprintf("  %-8s= \"%s\",\n", "name", m.Name))
+	b.WriteString(fmt.Sprintf("  %-8s= \"%s\",\n", "version", m.Version))
+	b.WriteString(fmt.Sprintf("  %-8s= \"%s\",\n", "summary", escape(m.Summary)))
+	b.WriteString(fmt.Sprintf("  %-8s= \"%s\",\n", "url", m.URL))
+	b.WriteString(fmt.Sprintf("  %-8s= \"%s\",\n", "sha256", m.SHA256))
+	if len(m.Deps) > 0 {
+		items := make([]string, len(m.Deps))
+		for i, d := range m.Deps {
+			items[i] = `"` + escape(d) + `"`
+		}
+		b.WriteString(fmt.Sprintf("  %-8s= { %s },\n", "deps", strings.Join(items, ", ")))
+	} else {
+		b.WriteString(fmt.Sprintf("  %-8s= {},\n", "deps"))
+	}
+	b.WriteString(fmt.Sprintf("  %-8s= { strip = 1 },\n", "archive"))
+	b.WriteString("}\n")
+	return b.String(), nil
+}

internal/zeta/manifest_test.go

@@ -0,0 +1,276 @@
+package zeta
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// validManifest returns a fully valid archive-mode manifest that every
+// table case can copy-and-mutate.
+func validManifest() *Manifest {
+	return &Manifest{
+		Name:    "hello",
+		Version: "1.0",
+		Summary: "A tiny demonstration program",
+		URL:     "https://example.org/packages/hello/hello-1.0.tar.gz",
+		SHA256:  "731887527d1a72c57d1e64bad85cc341a4285354e773b2cd277420b744df2943",
+		Archive: &Archive{Strip: 1},
+	}
+}
+
+func TestManifest(t *testing.T) {
+	tests := []struct {
+		name       string
+		mutate     func(m *Manifest)
+		wantErr    bool
+		wantErrSub string
+	}{
+		{
+			name:   "valid archive manifest",
+			mutate: func(m *Manifest) {},
+		},
+		{
+			name: "missing version",
+			mutate: func(m *Manifest) {
+				m.Version = ""
+			},
+			wantErr:    true,
+			wantErrSub: "missing version",
+		},
+		{
+			name: "bad sha256",
+			mutate: func(m *Manifest) {
+				m.SHA256 = "zzz"
+			},
+			wantErr:    true,
+			wantErrSub: "64 hex",
+		},
+		{
+			name: "archive without url",
+			mutate: func(m *Manifest) {
+				m.URL = ""
+			},
+			wantErr:    true,
+			wantErrSub: "archive mode requires a url",
+		},
+		{
+			name: "remote url without sha256",
+			mutate: func(m *Manifest) {
+				m.SHA256 = ""
+			},
+			wantErr:    true,
+			wantErrSub: "must declare sha256 for a remote url",
+		},
+		{
+			name: "self dep",
+			mutate: func(m *Manifest) {
+				m.Deps = []string{"hello>=1.0"}
+			},
+			wantErr:    true,
+			wantErrSub: "depends on itself",
+		},
+		{
+			name: "dep with bad operator",
+			mutate: func(m *Manifest) {
+				m.Deps = []string{"pcre2<<10.42"}
+			},
+			wantErr:    true,
+			wantErrSub: "bad dependency constraint",
+		},
+		{
+			name: "dep without operator",
+			mutate: func(m *Manifest) {
+				m.Deps = []string{"pcre2 10.42"}
+			},
+			wantErr:    true,
+			wantErrSub: "bad dependency constraint",
+		},
+		{
+			name: "dotdot in files",
+			mutate: func(m *Manifest) {
+				m.Files = []string{"../evil"}
+			},
+			wantErr:    true,
+			wantErrSub: "escapes the root",
+		},
+		{
+			name: "empty files entry",
+			mutate: func(m *Manifest) {
+				m.Files = []string{""}
+			},
+			wantErr:    true,
+			wantErrSub: "empty files entry",
+		},
+		{
+			name: "duplicate files entry",
+			mutate: func(m *Manifest) {
+				m.Files = []string{"usr/bin/hello", "usr/bin/hello"}
+			},
+			wantErr:    true,
+			wantErrSub: "twice",
+		},
+		{
+			name: "negative strip",
+			mutate: func(m *Manifest) {
+				m.Archive = &Archive{Strip: -1}
+			},
+			wantErr:    true,
+			wantErrSub: "non-negative integer",
+		},
+		{
+			name: "leading dot name",
+			mutate: func(m *Manifest) {
+				m.Name = ".hidden"
+			},
+			wantErr:    true,
+			wantErrSub: "invalid package name",
+		},
+		{
+			name: "slash in name",
+			mutate: func(m *Manifest) {
+				m.Name = "a/b"
+			},
+			wantErr:    true,
+			wantErrSub: "invalid package name",
+		},
+		{
+			name: "unsafe local url",
+			mutate: func(m *Manifest) {
+				m.URL = "/tmp/foo bar"
+				m.SHA256 = ""
+			},
+			wantErr:    true,
+			wantErrSub: "looks unsafe",
+		},
+		{
+			name: "valid deps with constraints",
+			mutate: func(m *Manifest) {
+				m.Deps = []string{"pcre2>=10.42", "libffi", "libz=1.2.13", "foo == 1.0"}
+			},
+		},
+		{
+			name: "local url without sha256 ok",
+			mutate: func(m *Manifest) {
+				m.URL = "/var/cache/zeta/hello-1.0.tar.gz"
+				m.SHA256 = ""
+			},
+		},
+		{
+			name: "valid files entries cleaned",
+			mutate: func(m *Manifest) {
+				m.Files = []string{"usr/bin/hello", "/usr/share/doc/", "./etc/zeta"}
+			},
+		},
+		{
+			name: "empty summary ok",
+			mutate: func(m *Manifest) {
+				m.Summary = ""
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			m := validManifest()
+			tt.mutate(m)
+			err := m.Validate()
+			if tt.wantErr {
+				if err == nil {
+					t.Fatalf("Validate() = nil, want error containing %q", tt.wantErrSub)
+				}
+				if tt.wantErrSub != "" && !strings.Contains(err.Error(), tt.wantErrSub) {
+					t.Fatalf("Validate() error = %q, want it to contain %q", err, tt.wantErrSub)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Validate() = %v, want nil", err)
+			}
+		})
+	}
+}
+
+func TestManifestSHA256Lowered(t *testing.T) {
+	m := validManifest()
+	m.SHA256 = strings.ToUpper(m.SHA256)
+	if err := m.Validate(); err != nil {
+		t.Fatalf("Validate() = %v, want nil (uppercase hex accepted)", err)
+	}
+	if m.SHA256 != strings.ToLower(m.SHA256) {
+		t.Fatalf("SHA256 = %q, want it lowercased", m.SHA256)
+	}
+}
+
+func TestManifestEmitFormat(t *testing.T) {
+	m := &Manifest{
+		Name:    "tool",
+		Version: "2.0",
+		Summary: "say \"hi\"\nnewline",
+		URL:     "https://example.org/packages/tool/tool-2.0.tar.gz",
+		SHA256:  "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+		Deps:    []string{"libz>=1.2.13", "pcre2"},
+		Archive: &Archive{Strip: 1},
+	}
+	want := `return {
+  name    = "tool",
+  version = "2.0",
+  summary = "say \"hi\"\nnewline",
+  url     = "https://example.org/packages/tool/tool-2.0.tar.gz",
+  sha256  = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+  deps    = { "libz>=1.2.13", "pcre2" },
+  archive = { strip = 1 },
+}
+`
+	got, err := m.Emit()
+	if err != nil {
+		t.Fatalf("Emit() error = %v", err)
+	}
+	if got != want {
+		t.Fatalf("Emit() output mismatch:\n--- got ---\n%s\n--- want ---\n%s", got, want)
+	}
+}
+
+func TestManifestEmitInvalid(t *testing.T) {
+	m := validManifest()
+	m.Version = ""
+	if _, err := m.Emit(); err == nil {
+		t.Fatal("Emit() = nil error, want validation error for missing version")
+	}
+}
+
+func TestManifestGolden(t *testing.T) {
+	m := &Manifest{
+		Name:    "hello",
+		Version: "1.0",
+		Summary: "A tiny demonstration program",
+		URL:     "https://example.org/packages/hello/hello-1.0.tar.gz",
+		SHA256:  "731887527d1a72c57d1e64bad85cc341a4285354e773b2cd277420b744df2943",
+		Deps:    []string{},
+	}
+	got, err := m.Emit()
+	if err != nil {
+		t.Fatalf("Emit() error = %v", err)
+	}
+
+	goldenPath := filepath.Join("..", "..", "testdata", "golden", "hello.package.lua")
+	if os.Getenv("UPDATE_GOLDEN") == "1" {
+		if err := os.MkdirAll(filepath.Dir(goldenPath), 0o755); err != nil {
+			t.Fatalf("MkdirAll: %v", err)
+		}
+		if err := os.WriteFile(goldenPath, []byte(got), 0o644); err != nil {
+			t.Fatalf("WriteFile golden: %v", err)
+		}
+		t.Logf("wrote golden %s", goldenPath)
+		return
+	}
+
+	want, err := os.ReadFile(goldenPath)
+	if err != nil {
+		t.Fatalf("ReadFile golden %s: %v (run UPDATE_GOLDEN=1 to regenerate)", goldenPath, err)
+	}
+	if got != string(want) {
+		t.Fatalf("Emit() does not match golden %s:\n--- got ---\n%s\n--- want ---\n%s", goldenPath, got, want)
+	}
+}

testdata/golden/hello.package.lua

@@ -0,0 +1,9 @@
+return {
+  name    = "hello",
+  version = "1.0",
+  summary = "A tiny demonstration program",
+  url     = "https://example.org/packages/hello/hello-1.0.tar.gz",
+  sha256  = "731887527d1a72c57d1e64bad85cc341a4285354e773b2cd277420b744df2943",
+  deps    = {},
+  archive = { strip = 1 },
+}

testdata/golden/mytool.build.sh

@@ -0,0 +1,29 @@
+#!/bin/sh
+set -eu
+
+pkgname='mytool'
+pkgver='1.0'
+pkgrel='1'
+arch='x86_64'
+url='https://example.org'
+
+srcdir="$PWD"
+pkgdir="$DESTDIR"
+
+msg() { :; }
+
+prepare() { :; }
+
+build() {
+  cd "$srcdir"
+  ./configure --prefix=/usr
+  make
+}
+
+package() {
+  cd "$srcdir"
+  make DESTDIR="$pkgdir" install
+}
+
+build
+package