Module validate 

Pre-flight syntax check for shell-sourced files.

Runs bash -n / zsh -n against each deployed shell source so that syntax errors in aliases.sh, profile.zsh etc. surface at dodot up time instead of silently breaking the user’s next shell startup. The interpreter’s stderr (which carries file: line N: error_message) is preserved verbatim into a sidecar file under the handler datastore so dodot status can show it later (3c).

This module does not invoke the staged file. It only parses it. bash -n / zsh -n are syntax-only — no commands run, no side effects on the user’s environment.

Sidecar layout: <data_dir>/packs/<pack>/shell/.errors/<filename>.err

• Written on a fresh syntax failure.
• Removed on a fresh syntax success (so a fix clears the prior error).
• Untouched when the interpreter is missing (we have no info either way).

Init-script generation already filters non-symlinks, so the .errors subdirectory does not end up sourced at shell startup.

Structs

NoopSyntaxChecker

SyntaxChecker that always returns SyntaxCheckResult::Ok. Used in tests to keep the validation pass deterministic and hermetic (no real bash/zsh invocations).

ShellValidationFailure

One file that failed pre-flight syntax check.

ShellValidationReport

Summary of one validation pass over the deployed shell sources.

SystemSyntaxChecker

Production SyntaxChecker that spawns real subprocesses.

Enums

SyntaxCheckResult

Constants

ERRORS_SUBDIR

Subdirectory (under each pack’s shell handler dir) where sidecar .err files live. Public so 3c (status) can read it back.

Traits

SyntaxChecker

Run a syntax-only check on a shell file.

Functions

error_sidecar_path

Path of the sidecar error file for one source.

validate_shell_sources

Iterate every deployed shell source, run a syntax check, and update the per-file sidecar files. Idempotent across runs: a previously failing file that’s been fixed gets its sidecar removed.