5.3 KiB
Decisions — tofu-core
Architectural choices and rationales discovered during work on this plan.
Auto-scaffolded by /start-work. Append new entries below - never overwrite.
Task 4: version → ver rename
version is a reserved keyword in D (conditional compilation). All struct fields bearing this name are renamed to ver — PackageIndex.ver, Recipe.ver, DepConstraint.ver, CacheManifest.ver, BinaryCheckResult.ver. This keeps the API readable while avoiding the keyword conflict. Downstream modules referencing these structs must use .ver for the version field.
Task 4: DepConstraint uses typed DepOp enum, not string op
The Lua reference stores op as a string (nil, ">=", "==", etc.). In D we use a typed DepOp enum (ge, le, eq, ne, gt, lt, none) for type safety and exhaustive switching. The parse factory handles string-to-enum conversion at parse time.
Task 4: BuildPlan is a plain container — no sorting
The plan specifies that order() returns entries in deps-first order guaranteed by the caller. The struct itself is just a container with add() and order() — no topological sort or dependency resolution. Sorting logic belongs in a later module (tofu.resolver or similar).
Task 4: Single exception type TypesException
One exception class for the entire types module — no separate subclasses per error category. The parse failures (bad dep spec, invalid pool) all throw TypesException with a descriptive message. Callers catch TypesException for all type-parsing errors.
Task 4: Manual char scanning for dep spec parsing
Rather than pulling in std.regex, the parser uses hand-written isNameChar() and isWhite() helpers with a simple position cursor. This keeps the module dependency-light (only std.ascii). The logic is a direct 1:1 port of the Lua reference patterns: [A-Za-z0-9_.+-] for names/versions, whitespace [ \t] for separators.
Task 12: delegate keyword in test lambdas for delegate-typed parameters
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).
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.