Files
holocron/plugins/git/skills/pc-run/references/failure-patterns.md
Defame1297 93d3263f8c fix(pc-run): rebind the clean gate and fixer-hook rule to every branch
SKILL.md tells a dispatching agent to read the matching reference file
"and no other". The retrofit moved the `pre-commit clean` confirmation
gate out of the always-loaded body into references/clean.md, but
references/failure-patterns.md — loaded by the diagnosis route, not the
clean route — prescribes `pre-commit clean` with no gate at all. So "why
is this hook failing" could wipe the machine-wide cache at
~/.cache/pre-commit for every repo without asking.

The gate returns to the body, where every branch loads it, and is
restated at the point of use in failure-patterns.md. It is its own
section rather than a Gotchas bullet because folding it in pushed the
Gotchas ratio to 41%, whose only suggested remedy is moving it back to
references/ — the move that caused this.

The fixer-hook rule had the same shape: reachable only behind "if the
cause is not obvious from the output", which is false precisely when
pre-commit prints `- files were modified by this hook`. The fix
(`git add -u && git commit`) and the prohibition on `pre-commit install -f`
are now unconditional, and the two weakened pointers that stranded them
are restored.

Found by an independent review of this branch.

Refs #99
2026-08-30 20:50:45 +00:00

4.7 KiB

source_keys
source_keys
context7-pre-commit-com
pre-commit-com

Hook Failure Patterns

Common hook failure causes and concrete next-step suggestions.

Hook modified files — commit blocked

Cause: A fixer hook (e.g. trailing-whitespace, end-of-file-fixer, pretty-format-json) modified staged files. The commit is blocked because the staged version is now stale.

Fix: Re-stage and recommit.

git add -u
git commit -m "same message"

Do NOT reach for pre-commit install -f here. That flag overwrites existing hook files in .git/hooks/; it has nothing to do with re-staging.

Secret detected (gitleaks)

Not sourced from the pre-commit research corpus (context7-pre-commit-com/pre-commit-com cover pre-commit itself, not gitleaks) — general tool knowledge, verify against gitleaks' own docs if precision matters.

Cause: gitleaks found a high-entropy string or known secret pattern in a staged file.

Suggestions:

  • If it's a false positive: add a # gitleaks:allow inline comment, or add the path to .gitleaksignore.
  • If it's a real secret: remove it from the file, rotate the credential, then commit.

Shellcheck warning

Not sourced from the pre-commit research corpus — general tool knowledge, verify against shellcheck's own docs if precision matters.

Cause: shellcheck found a shell script issue. The output includes the file path, line number, and SC-code.

Fix: Look up the SC-code on shellcheck.net or pass --explain SCxxxx to shellcheck for a detailed explanation. The most common fixes:

  • SC2086 (unquoted variable): wrap in double quotes.
  • SC2046 (unquoted command substitution): wrap in double quotes.
  • SC2181 (check exit code of $?): use if command; then directly.

check-hooks-apply fails

Cause: A hook's files/types filter matches zero files in the repo — the hook is dead weight.

Fix: Broaden the filter, or remove the hook if it no longer applies to this repo.

check-useless-excludes fails

Cause: An exclude pattern matches no files.

Fix: Remove or fix the pattern.

SSH cloning fails in CI

Cause: The CI environment lacks SSH credentials to clone hook repos over SSH.

Fix: Export SSH_AUTH_SOCK in the CI environment, or switch hook repo URLs to HTTPS.

HTTP proxy needed

Cause: The CI/sandbox network requires a proxy to reach hook repos.

Fix:

export http_proxy=http://proxy.example.com:3128
export https_proxy=http://proxy.example.com:3128
export no_proxy=localhost,127.0.0.1

rev is a branch name — autoupdate broke it

Cause: Branch refs are mutable and drift over time; pre-commit resolves them once at install time, so pinning to a branch name (instead of a tag or commit SHA) leads to silent version drift.

Fix:

pre-commit autoupdate     # finds the latest tag and rewrites rev in place

pretty-format-json fails but doesn't fix

Cause: pretty-format-json requires args: [--autofix] to modify files. Without it, the hook only fails.

Fix: The user (or pc-author) must add args: [--autofix] to the hook override in .pre-commit-config.yaml.

Environment stale or broken

Cause: A hook's cached environment is corrupted or out of date.

Fix: pre-commit clean is gated. It wipes the machine-wide cache at ~/.cache/pre-commit, shared by every repo on the box, so get explicit confirmation before running it — "This will wipe the entire pre-commit cache. All hook environments will be re-downloaded on next run. Proceed?"

pre-commit clean          # gated — confirm with the user first
pre-commit install-hooks  # rebuild everything

Or less destructively, needing no confirmation:

pre-commit gc             # remove only unused environments

Hooks don't run on git commit

Cause: pre-commit install was never run in this clone.

Fix: pre-commit install. Git hooks are per-clone — they are not committed to the repo.

Hook runs but matches wrong files (or no files)

Cause: The files: pattern uses re.search() not full-string match. A pattern that looks correct may match unexpectedly.

Diagnosis: identify-cli <filename> shows the type tags for a file. Verify types: filters against these.

stages mismatch — hook never fires

Cause: Hook is defined for a stage (e.g. pre-push) but pre-commit install was not run with -t pre-push.

Fix:

pre-commit install -t pre-commit -t pre-push -t commit-msg

Or add default_install_hook_types to .pre-commit-config.yaml and re-run pre-commit install.

validate-config schema error

Common causes:

  • Missing id under a hook block
  • Missing rev under a non-local repo block
  • repo: local hook missing language or entry
  • Indentation error (valid YAML but invalid pre-commit schema)