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: v6.0.0  # 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-executables-have-shebangs

Checks that non-binary executables have a proper shebang.

check-illegal-windows-names

Check for files that cannot be created on Windows.

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. Note that this hook WILL remove blank lines and does NOT respect any comments. All newlines will be converted to line feeds (\n).

The following arguments are available:

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

fix-byte-order-marker

removes UTF-8 byte order marker

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 constraints.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
• fix-encoding-pragma: instead use pyupgrade
• check-docstring-first: fundamentally flawed, deprecated without replacement.

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