pre-commit-hooks

Some out-of-the-box hooks for pre-commit.

See also: https://github.com/pre-commit/pre-commit

Using pre-commit-hooks with pre-commit

Add this to your .pre-commit-config.yaml

-   repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v4.3.0  # Use the ref you want to point at
    hooks:
    -   id: trailing-whitespace
    # -   id: ...

Hooks available

check-added-large-files

Prevent giant files from being committed.

• Specify what is "too large" with args: ['--maxkb=123'] (default=500kB).
• Limits checked files to those indicated as staged for addition by git.
• If git-lfs is installed, lfs files will be skipped (requires git-lfs>=2.2.1)
• --enforce-all - Check all listed files not just those staged for addition.

check-ast

Simply check whether files parse as valid python.

check-builtin-literals

Require literal syntax when initializing empty or zero Python builtin types.

• Allows calling constructors with positional arguments (e.g., list('abc')).
• Allows calling constructors from the builtins (__builtin__) namespace (builtins.list()).
• Ignore this requirement for specific builtin types with --ignore=type1,type2,….
• Forbid dict keyword syntax with --no-allow-dict-kwargs.

check-case-conflict

Check for files with names that would conflict on a case-insensitive filesystem like MacOS HFS+ or Windows FAT.

check-docstring-first

Checks for a common error of placing code before the docstring.

check-executables-have-shebangs

Checks that non-binary executables have a proper shebang.

check-json

Attempts to load all json files to verify syntax.

check-merge-conflict

Check for files that contain merge conflict strings.

• --assume-in-merge - Allows running the hook when there is no ongoing merge operation

check-shebang-scripts-are-executable

Checks that scripts with shebangs are executable.

check-symlinks

Checks for symlinks which do not point to anything.

check-toml

Attempts to load all TOML files to verify syntax.

check-vcs-permalinks

Ensures that links to vcs websites are permalinks.

• --additional-github-domain DOMAIN - Add check for specified domain. Can be repeated multiple times. for example, if your company uses GitHub Enterprise you may use something like --additional-github-domain github.example.com

check-xml

Attempts to load all xml files to verify syntax.

check-yaml

Attempts to load all yaml files to verify syntax.

• --allow-multiple-documents - allow yaml files which use the multi-document syntax
• --unsafe - Instead of loading the files, simply parse them for syntax. A syntax-only check enables extensions and unsafe constructs which would otherwise be forbidden. Using this option removes all guarantees of portability to other yaml implementations. Implies --allow-multiple-documents.

debug-statements

Check for debugger imports and py37+ breakpoint() calls in python source.

destroyed-symlinks

Detects symlinks which are changed to regular files with a content of a path which that symlink was pointing to. This usually happens on Windows when a user clones a repository that has symlinks but they do not have the permission to create symlinks.

detect-aws-credentials

Checks for the existence of AWS secrets that you have set up with the AWS CLI. The following arguments are available:

• --credentials-file CREDENTIALS_FILE - additional AWS CLI style configuration file in a non-standard location to fetch configured credentials from. Can be repeated multiple times.
• --allow-missing-credentials - Allow hook to pass when no credentials are detected.

detect-private-key

Checks for the existence of private keys.

double-quote-string-fixer

This hook replaces double quoted strings with single quoted strings.

end-of-file-fixer

Makes sure files end in a newline and only a newline.

file-contents-sorter

Sort the lines in specified files (defaults to alphabetical). You must provide the target files as input, for example:

    -   id: file-contents-sorter
        files: \.gitignore

Note that this hook WILL remove blank lines and does NOT respect any comments.

fix-byte-order-marker

removes UTF-8 byte order marker

fix-encoding-pragma

Add # -*- coding: utf-8 -*- to the top of python files.

• To remove the coding pragma pass --remove (useful in a python3-only codebase)

The following arguments are available:

• --ignore-case - fold lower case to upper case characters.
• --unique - ensure each line is unique.

forbid-new-submodules

Prevent addition of new git submodules.

This is intended as a helper to migrate away from submodules. If you want to ban them entirely use forbid-submodules

forbid-submodules

forbids any submodules in the repository.

mixed-line-ending

Replaces or checks mixed line ending.

• --fix={auto,crlf,lf,no}
  • auto - Replaces automatically the most frequent line ending. This is the default argument.
  • crlf, lf - Forces to replace line ending by respectively CRLF and LF.
    • This option isn't compatible with git setup check-in LF check-out CRLF as git smudge this later than the hook is invoked.
  • no - Checks if there is any mixed line ending without modifying any file.

name-tests-test

verifies that test files are named correctly.

• --pytest (the default): ensure tests match .*_test\.py
• --pytest-test-first: ensure tests match test_.*\.py
• --django / --unittest: ensure tests match test.*\.py

no-commit-to-branch

Protect specific branches from direct checkins.

• Use args: [--branch, staging, --branch, main] to set the branch. Both main and master are protected by default if no branch argument is set.
• -b / --branch may be specified multiple times to protect multiple branches.
• -p / --pattern can be used to protect branches that match a supplied regex (e.g. --pattern, release/.*). May be specified multiple times.

Note that no-commit-to-branch is configured by default to always_run. As a result, it will ignore any setting of files, exclude, types or exclude_types. Set always_run: false to allow this hook to be skipped according to these file filters. Caveat: In this configuration, empty commits (git commit --allow-empty) would always be allowed by this hook.

pretty-format-json

Checks that all your JSON files are pretty. "Pretty" here means that keys are sorted and indented. You can configure this with the following commandline options:

• --autofix - automatically format json files
• --indent ... - Control the indentation (either a number for a number of spaces or a string of whitespace). Defaults to 2 spaces.
• --no-ensure-ascii preserve unicode characters instead of converting to escape sequences
• --no-sort-keys - when autofixing, retain the original key ordering (instead of sorting the keys)
• --top-keys comma,separated,keys - Keys to keep at the top of mappings.

requirements-txt-fixer

Sorts entries in requirements.txt and removes incorrect entry for pkg-resources==0.0.0

sort-simple-yaml

Sorts simple YAML files which consist only of top-level keys, preserving comments and blocks.

Note that sort-simple-yaml by default matches no files as it enforces a very specific format. You must opt in to this by setting files, for example:

    -   id: sort-simple-yaml
        files: ^config/simple/

trailing-whitespace

Trims trailing whitespace.

• To preserve Markdown hard linebreaks use args: [--markdown-linebreak-ext=md] (or other extensions used by your markdownfiles). If for some reason you want to treat all files as markdown, use --markdown-linebreak-ext=*.
• By default, this hook trims all whitespace from the ends of lines. To specify a custom set of characters to trim instead, use args: [--chars,"<chars to trim>"].

Deprecated / replaced hooks

• check-byte-order-marker: instead use fix-byte-order-marker

As a standalone package

If you'd like to use these hooks, they're also available as a standalone package.

Simply pip install pre-commit-hooks