perf(context): memoize idempotent git/gh probes within process#586
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NagyVikt merged 1 commit intoMay 16, 2026
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Add a process-scoped cache in src/context.js that wraps cp.spawnSync via a
new cachedSpawn helper, then route git/index.js and doctor/index.js spawns
through it. Cache lifetime is the lifetime of one Node process (a single
gx invocation) -- no disk cache, no TTL beyond process exit.
The allowlist is intentionally narrow and only covers probes whose answer
is invariant within a single gx run under gx's own writes:
* git rev-parse --show-toplevel | --git-common-dir | --git-dir |
--show-cdup | --show-superproject-working-tree | --is-inside-work-tree |
--is-inside-git-dir | --is-bare-repository | --show-prefix
* git --version, gh --version
* which / command / type lookups
Everything else (git status, diff, for-each-ref, rev-list, ls-files,
worktree list, branch --show-current, show-ref, merge-base, config --get,
remote get-url, ls-remote, gh auth status, gh pr/repo/issue view/list,
gh api *) falls through to a real spawn each time. Doctor and similar
flows mutate refs, the index, and config mid-run, so caching those reads
would feed stale answers to later steps.
Writes are never cached: anything taking stdin, anything with non-pipe
stdio, every git write verb (commit, push, pull, fetch, merge, rebase,
checkout, switch, reset, restore, clean, stash, tag, add, rm, mv, apply,
worktree add/remove/prune, branch -d/-D, config set/unset, submodule
update), every gh write verb (pr create/merge/close/edit/review/comment,
issue *, release *, repo create/delete, auth login/logout, api -X
POST/PATCH/PUT/DELETE) is rejected by the allowlist.
Honors two env knobs:
* GUARDEX_PROBE_TRACE=1 prints [probe] / [probe-hit] lines on stderr.
Made it possible to count duplicate spawns in gx doctor (23 baseline
spawnSync calls -> 18 real spawns + 5 cache hits) without altering
user-facing output.
* GUARDEX_PROBE_CACHE=0 disables the cache entirely (escape hatch).
Verification: node --test test/*.test.js shows the same set of pre-
existing failures vs an unmodified tree (no new regressions). gx doctor
and gx status produce identical user-facing output before and after.
NagyVikt
deleted the
agent/claude/perf-memoize-git-gh-probes-2026-05-16-02-45
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