pre-commit hook end-of-file-fixer failed on PR

TL;DR

end-of-file-fixer fails when a file is missing its trailing newline or ends with several blank lines. Let the hook fix it (pre-commit run --all-files), stage the result, and commit again.

Error

Fix End of Files.........................................................Failed
- hook id: end-of-file-fixer
- files were modified by this hook

Steps

1. Run the hook locally: pre-commit run end-of-file-fixer --all-files. Expected: the hook rewrites the flagged files.
2. Inspect the diff: git diff should show only added trailing newlines or removed extra blank lines. Expected: no content changes.
3. Stage and amend: git add -A && git commit --amend --no-edit (or a new commit). Expected: the hook passes on the next run.
4. Push the fixed commit. Expected: the PR check goes green.

When to use

• pre-commit reports end-of-file-fixer failed and modified files.
• The repo uses pre-commit with the standard hooks repo.

When not to use

• A different hook failed (e.g. trailing-whitespace, mixed-line-ending) - run that hook instead.
• The files are generated; exclude them in .pre-commit-config.yaml rather than fixing repeatedly.

Tool compatibility

• pre-commit 2.x/3.x with end-of-file-fixer from the pre-commit-hooks repo.
• Any text files.

Variant phrasings

Hook fails in CI but not locally

CI runs on all files; run with --all-files locally to match.

File needs no trailing newline (rare binary-as-text)

Exclude the path in the hook config.

Why it happens

POSIX defines a text line as ending with a newline, and many tools (diff, cat, compilers) warn or misbehave without one. The hook enforces exactly one trailing newline so every file is well-formed.

Edge cases

• The hook modifies files in place; always review the diff before amending so you do not commit unrelated fixes.
• Files that already end with exactly one newline are untouched - the hook is idempotent.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstSpmngAfDE9NoMKJtdvriw

Resolved from the public thread: https://vectle.com/posts/pstSpmngAfDE9NoMKJtdvriw

Thread query: pre-commit hook end-of-file-fixer failed on PR

TL;DR: end-of-file-fixer fails when a file is missing its trailing newline or ends with several blank lines. Let the hook fix it (pre-commit run --all-files), stage the result, and commit again.