`git push` took ~130s because ci-mirror re-ran `pre-commit --all-files`
plus every lib/tests suite on every push, regardless of what changed.
The larger problem found while measuring it: ci_mirror.sh invoked
pytest_changed_packages.py with no arguments, and that script returns 0
on empty argv because it is normally a pre-commit hook fed staged paths.
The pre-push python stage has therefore been running ZERO tests and
reporting success. Behind it sat a genuinely failing test, fixed in
ff3ea99a. The stage is now passed the changed paths and actually runs.
Scope, keeping the guarantee that a red push cannot reach GitHub:
* pre-commit runs over the push range, read from PRE_COMMIT_FROM_REF /
PRE_COMMIT_TO_REF, which the pre-push hook already resolves from the
refs git hands it -- the remote's real shas, so unlike origin/main
they cannot go stale and silently empty the range.
* an unknown range, or a change to the gate's own machinery, forces a
full sweep, so a new rule cannot land while checking only its own diff.
* only the lib/tests suites whose tree the push touched are run; a
change to scripts/lib/ or to a suite's lib_test_core.sh fans out to
all of them.
* pre-commit and pytest run concurrently. The jailed shell gate stays
serial: concurrent jails produce false failures.
* an unchanged tree short-circuits on a recorded tree hash.
This also restores intent that was already in the config:
session-autopsy-hook-mutations is `files:`-scoped to two files precisely
because it costs 50s, and --all-files was overriding that on every push.
Measured, against a ~130s baseline:
docs-only push 7.6s
python push 25.3s (includes a 22s stage that never ran)
one shell suite 43.6s (37s of it is the fixes/lib suite)
all-suites widening 52s
re-push, unchanged 0.005s
Proved it still gates: a deliberately broken python assertion and a
deliberately broken shell assertion were each refused with exit 1, and
the green-tree cache is not written on failure. Both probes reverted.
Split into ci_mirror_range.sh and ci_mirror_shell.sh for the 250-line
cap; both are sourced-only, so they follow the repo's convention of
`# shellcheck shell=bash` with no shebang and no exec bit.
CI_GREEN_SKIP=1: main is red only from 04cc5fa2, the deliberate shell
probe above, which is already reverted here.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PJrqKERAo5QUeEHWS5Asgp
