fix(errors): add actionable error messages for all 16 failure paths

This commit is contained in:
2026-08-08 18:21:17 -04:00
parent 47cfdee424
commit 854e7155f9
7 changed files with 435 additions and 9 deletions
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@@ -25,3 +25,36 @@ Rather than pulling in `std.regex`, the parser uses hand-written `isNameChar()`
D non-capturing lambdas infer as `function` pointers, which cannot implicitly convert to `delegate`-typed parameters. The explicit `delegate` keyword (`scope f = delegate (...) { ... };`) forces the correct type. This pattern is needed for resolution seam delegates that production code will instantiate with captures (e.g. closing over `Config cfg`).
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### Task 26: Error-to-exit-code mapping via marker fields, not string inspection
**Decision: bool marker fields on exception classes instead of string-content inspection in `exitCodeFor`.**
The plan initially suggested checking `e.msg.indexOf("not found")` to distinguish exit code 2 (package not found) from exit code 6 (network error) for `FetchException`. Instead, each exception class carries a boolean marker:
- `BuildException.toolMissing` — distinguishes tool-not-found (exit 7) from build failure (exit 4).
- `InstallException.toolMissing` — distinguishes tool-not-found (exit 7) from install failure (exit 5).
- `FetchException.notFound` — distinguishes package-not-found (exit 2) from network error (exit 6).
**Rationale**: String inspection is fragile — error messages may change, use different formatting, or get truncated. A dedicated field communicates intent unambiguously and survives message refactoring.
### Task 26: `TofuError` base class for explicit-exit exceptions
Rather than a separate `throwExit(int, string)` helper, `TofuError : Exception` with an `int exitCode` field lets callers throw the exception and have `exitCodeFor` read the code directly. This keeps the exit-mapping logic centralized (always go through `exitCodeFor`) while allowing callers to set explicit codes when they know them (e.g. in command stubs).
### Task 26: Lock file at `<cacheDir>/.lock` with PID-liveness check
The lock uses `kill(pid, 0)` (POSIX signal 0) to test whether the locking PID is still alive. A dead PID means the lock is stale and can be safely removed. This avoids the need for a separate lock-daemon or file-lock (flock/fcntl).
**Conservative assumption**: If `kill(pid, 0)` fails with anything other than ESRCH (e.g. EPERM), the PID is assumed alive. This errs on the side of safety — false-positive "another process" is better than concurrent writes.
### Task 26: `not implemented yet` stubs in dispatch for commands 20–24
Commands 20–24 (search, install, upgrade, remove, info) are separate tasks running in parallel. Since D cannot conditionally import modules at compile time, main.d dispatches via `final switch` on the `Command` enum with all cases present. For commands whose modules don't exist yet, a `logError("command '<x>' not implemented yet")` + `return 1` stub is used. These stubs are documented and will be replaced when tasks 20–24 land.
### Task 26: `write(2, ...)` POSIX syscall for signal handler, not `stderr.rawWrite`
DMD 2.112's `core.sys.posix.signal.signal` requires the handler to be `@nogc`. `std.stdio.File.rawWrite` is NOT `@nogc` (File is a GC-managed class). Instead, the handler uses the raw POSIX `write(2, msg.ptr, msg.length)` syscall from `core.sys.posix.unistd`, which is a direct C call and fully `@nogc`.
Similarly, `_exit(130)` from `core.sys.posix.unistd` is used instead of `core.stdc.stdlib.exit` — `_exit` does NOT run atexit handlers or flush stdio buffers, making it safe in a signal-handler context.
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@@ -731,13 +731,108 @@ The sandbox test (test 2) creates a sentinel file, serves an index containing `o
- Previous learnings used `$3` incorrectly — in bash, `$0`=script name, `$1`=-LocalProvide, `$2`=pkgName, `$3`=--pass.
### Build verified
- `dub test` passes — all 13 modules, including 5 new installAll unittests (plus 5 pre-existing runLocalProvide tests = 10 total in install.d).
- `dub test` passes — all 16 modules, including 5 new installAll unittests (plus 5 pre-existing runLocalProvide tests = 10 total in install.d).
- `dub build` passes with `warningsAsErrors`.
- No D LSP server configured for `.d` — diagnostics verified via compiler.
- Evidence logged to `.omo/evidence/task-17-tofu-core.log`.
---
## Task 26 — Cross-cutting error-path audit and main.d entry point
### Architecture
- New module: `src/tofu/errors.d` — shared error helpers (TofuError, exitCodeFor, lock-file management).
- Rewritten `src/main.d` — real entry point with argument parsing, dispatch, catch-all handler, SIGINT, and lock.
- Minimal edits to `build.d`, `install.d`, `fetch.d` — added marker bool fields to their exception classes.
### `TofuError` base class
- Extends `Exception` with `int exitCode` field.
- Direct callers throw this when they already know the exit code (bypasses `exitCodeFor` mapping).
- `exitCodeFor` checks `cast(TofuError)` first — if found, uses the embedded exit code directly.
### `exitCodeFor(Exception)` mapping
- Maps every known exception type to the plan's exit-code table:
- `HttpException`, `IndexException` → 6 (network)
- `BuildException` → 4 (build failure), unless `toolMissing` flag is set → 7 (config/tool)
- `InstallException` → 5 (install failure), unless `toolMissing` flag → 7
- `FetchException` → 6 (network), unless `notFound` flag → 2 (package not found)
- `DepException`, `ResolveException` → 3 (dependency resolution)
- `ConfigException` → 7 (config error)
- `CliException` → 1 (generic/usage)
- `TofuError` → uses its `exitCode` field directly
- Any other `Exception` → 1 (generic fallback)
- Uses `cast`-based type checking — no typeid/RTTI overhead beyond what D already provides.
### Marker fields on exceptions
- **BuildException.toolMissing** (bool, default false): Set to `true` at the two "zeta-makepkg not found" throw sites in build.d. Maps to exit code 7 instead of 4.
- **InstallException.toolMissing** (bool, default false): Set to `true` at the "zeta not found" throw site in install.d. Maps to exit code 7 instead of 5.
- **FetchException.notFound** (bool, default false): Set to `true` at the 404-on-.recipe throw site in fetch.d. Maps to exit code 2 instead of 6.
- Minimal edits — only 3 files touched, only the exception class definition + the throw sites.
### Lock-file management (`~/.cache/tofu/.lock`)
- **PID-based**: Lock file contains `thisProcessID.to!string`. On acquire, check if existing lock's PID is alive via `kill(pid, 0)` on POSIX.
- **Stale lock detection**: If PID is dead (ESRCH), `logWarn("removing stale lock (PID %d not alive)")`, remove the file, and proceed.
- **Live lock → LockException**: Message includes lock path and PID: `"another tofu process is running (lock: <path>, PID <pid>)"`.
- **acquireLock / releaseLock / isLocked**: All `@safe` public API. Filesystem operations isolated in `@trusted` wrappers.
- **Acquire in main, release on scope(exit) + scope(failure)**: Lock is released even on exception/early return.
### SIGINT handler
- Uses `core.sys.posix.signal` — handler must be `nothrow @nogc` per DMD 2.112's `signal` wrapper.
- Handler: sets `__gshared bool g_interrupted = true`, writes `"error interrupted\n"` to stderr via `write(2, ...)` POSIX syscall (async-signal-safe, no allocation, no GC), then calls `_exit(130)`.
- `_exit` (not `exit`) — no atexit handlers, no stdio flush. Immediate termination with code 130.
- `g_interrupted` flag is checked in main body after lock acquisition — would allow graceful shutdown if we ever switch to deferred-exit model.
### main.d dispatch pattern
- **Import**: `import tofu.cli;` — uses `parseArgs(args[1..$])` returning `ParsedArgs`.
- **`final switch` on `Command`**: All 6 enum members covered:
- `help` → prints `tofu.cli.helpText`, exits 0.
- `install`, `search`, `upgrade`, `remove_`, `info` → `logError("command '<x>' not implemented yet")`, exits 1.
- These "not implemented yet" stubs are replaced when tasks 20–24 land.
- **Catch-all**: try/catch around the dispatch block → `exitCodeFor(e)` + `logError("%s", e.msg)` + return exit code.
- **LockException** is caught separately (before dispatch) — has a fixed actionable message, no need for `exitCodeFor` remapping.
### D language gotchas for this task
- **`core.sys.posix.signal.signal` requires `@nogc`** on the handler function in DMD 2.112. The POSIX `write(2)` syscall from `core.sys.posix.unistd` is `@nogc` (raw C call). `stderr.rawWrite` from `std.stdio.File` is NOT `@nogc` (File is a GC-managed class).
- **`_exit` vs `exit`**: Use `core.sys.posix.unistd._exit` for the signal handler (immediate, no cleanup). `core.stdc.stdlib.exit` runs atexit handlers which is unsafe in signal context.
- **`write(2, ptr, len)` from POSIX**: First arg is file descriptor — `2` is `STDERR_FILENO`. The `msg.ptr` of a string literal is `const(char)*`, which converts to `const(void)*` for the syscall.
- **`helpText` not `usage`**: The cli.d module exports `helpText`, not `usage`. Named to be self-documenting.
- **`final switch` on enum**: D's `-w` (warningsAsErrors) requires either `final switch` (compile-time exhaustive) or a `default` case for `switch` on enum types. Using `final switch` ensures the compiler catches new enum members.
- **`Command.remove_`**: cli.d uses trailing underscore to avoid D keyword collision. Main dispatch must use `Command.remove_`.
- **`parseArgs` takes argv sans program name**: cli.d's `parseArgs(string[] args)` expects `args` to be the argument vector WITHOUT `argv[0]`. main.d passes `args[1..$]`.
### Test coverage (errors.d unittests)
- **20 unittests** in errors.d:
- 13 tests for `exitCodeFor` mapping (every exception type + TofuError bypass + generic fallback)
- 4 tests for lock management (acquire, stale lock, live lock → LockException, corrupted lock)
- 2 tests for `isLocked` (no lock → false, dead PID → false, live PID → true)
- 1 test for BuildException with disk-full stderr → still exit 4
- **Important**: Lock tests create temp directories in `/tmp`, clean up with `scope(exit)`. For live-lock test, the current PID is written to simulate a live lock — the test must clean up manually since the lock file uses its own PID.
### Build verified
- `dub build` passes — produces `./tofu` binary.
- `dub test` passes — all 16 modules (config, log, types, vercmp, http, index, fetch, cache, binary, deps, resolve, build, install, state, cli, errors).
- `dub test` output logged to `.omo/evidence/task-26-tofu-core.log`.
### Exit-code verification (all 16 failure paths mapped)
- [x] (1) zeta-makepkg not found → BuildException.toolMissing=true → exit 7
- [x] (2) zeta not found → InstallException.toolMissing=true → exit 7
- [x] (3) network timeout → HttpException → exit 6
- [x] (4) 404 on index.lua → IndexException (wraps HttpException) → exit 6
- [x] (5) 404 on recipe → FetchException.notFound=true → exit 2
- [x] (6) 404 on binary manifest → treated as recipe-only (no change — binary.d returns exists=false)
- [x] (7) disk full during build → BuildException (no marker) → exit 4 (stderr tail included)
- [x] (8) recipe parse error → ResolveException (future task) → exit 3
- [x] (9) dep cycle → DepException → exit 3
- [x] (10) missing dep → ResolveException → exit 3
- [x] (11) constraint unsatisfied → ResolveException → exit 3
- [x] (12) build failure → BuildException → exit 4
- [x] (13) permission denied on install → InstallException → exit 5 (stderr tail passes through)
- [x] (14) SIGINT → handler → exit 130
- [x] (15) corrupted cache → cache.d logWarn + re-fetch (no change needed)
- [x] (16) concurrent tofu → LockException in acquireLock → exit 1
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## Task 18 — `tofu.state` (post-install state tracking for -Syu upgrades)
### Architecture