check-one-function-per-file.yml

Enforce the one-function-definition-per-file rule across repository code files (.R, .py, .sh, .js, .ts, .jl). The check scans code files to verify that each file defines at most one top-level function, keeping code modular, searchable, and cleanly diffable.

Files that genuinely require multiple function definitions can opt out by adding a comment directive near the top of the file:

# check-one-function-per-file: allow-multiple

Inputs

Input	Type	Default	Description
path	string	'.'	Target directory or file path to scan.
paths-ignore	string	'.git, .github, tests, test, vendor, scratch, _site, node_modules, .pytest_cache, .venv, venv'	Comma- or newline-separated paths or glob patterns to ignore.
extensions	string	'.R, .r, .py, .sh, .bash, .js, .ts, .mjs, .cjs, .jl'	Comma- or space-separated list of file extensions to check.
opt-out-comment	string	''	Optional custom comment string to treat as an opt-out directive.
base-ref	string	''	Git ref to diff against for diff-scoped checking (e.g. origin/main). On pull requests and pushes, defaults to the PR base ref or previous commit automatically for diff-scoping.
fail	boolean	true	Whether to fail the workflow if multiple function definitions are detected.
python-version	string	'3.x'	Python version to set up.

Permissions

Only contents: read (the default), so no permissions: block is needed.

Example

name: Check one function per file
on:
  push: { branches: [main] }
  pull_request:
  workflow_dispatch:
jobs:
  check:
    uses: Morrison-Lab/gha/.github/workflows/check-one-function-per-file.yml@v2

See the examples/ directory for caller stubs (e.g. examples/check-one-function-per-file.yml).