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diff --git a/docs/code-quality/lint/usage.rst b/docs/code-quality/lint/usage.rst new file mode 100644 index 0000000000..49e0ac81cc --- /dev/null +++ b/docs/code-quality/lint/usage.rst @@ -0,0 +1,138 @@ +Running Linters Locally +======================= + +Using the Command Line +---------------------- + +You can run all the various linters in the tree using the ``mach lint`` command. Simply pass in the +directory or file you wish to lint (defaults to current working directory): + +.. parsed-literal:: + + ./mach lint path/to/files + +Multiple paths are allowed: + +.. parsed-literal:: + + ./mach lint path/to/foo.js path/to/bar.py path/to/dir + +To force execution on a directory that would otherwise be excluded: + +.. parsed-literal:: + + ./mach lint -n path/in/the/exclude/list + +``Mozlint`` will automatically determine which types of files exist, and which linters need to be run +against them. For example, if the directory contains both JavaScript and Python files then mozlint +will automatically run both ESLint and Flake8 against those files respectively. + +To restrict which linters are invoked manually, pass in ``-l/--linter``: + +.. parsed-literal:: + + ./mach lint -l eslint path/to/files + +You can see a list of the available linters by running: + +.. parsed-literal:: + + ./mach lint --list + +Finally, ``mozlint`` can lint the files touched by outgoing revisions or the working directory using +the ``-o/--outgoing`` and ``-w/--workdir`` arguments respectively. These work both with mercurial and +git. In the case of ``--outgoing``, the default remote repository the changes would be pushed to is +used as the comparison. If desired, a remote can be specified manually. In git, you may only want to +lint staged commits from the working directory, this can be accomplished with ``--workdir=staged``. +Examples: + +.. parsed-literal:: + + ./mach lint --workdir + ./mach lint --workdir=staged + ./mach lint --outgoing + ./mach lint --outgoing origin/master + ./mach lint -wo + +.. _lint-vcs-hook: + +Using a VCS Hook +---------------- + +There are also both pre-commit and pre-push version control hooks that work in +either hg or git. To enable a pre-push hg hook, add the following to hgrc: + +.. parsed-literal:: + + [hooks] + pre-push.lint = python:./tools/lint/hooks.py:hg + + +To enable a pre-commit hg hook, add the following to hgrc: + +.. parsed-literal:: + + [hooks] + pretxncommit.lint = python:./tools/lint/hooks.py:hg + + +To enable a pre-push git hook, run the following command: + +.. parsed-literal:: + + $ ln -s ../../tools/lint/hooks.py .git/hooks/pre-push + + +To enable a pre-commit git hook, run the following command: + +.. parsed-literal:: + + $ ln -s ../../tools/lint/hooks.py .git/hooks/pre-commit + +Note that the symlink will be interpreted as ``.git/hooks/../../tools/lint/hooks.py``. + +Automatically Fixing Lint Errors +-------------------------------- + +``Mozlint`` has a best-effort ability to fix lint errors: + +.. parsed-literal:: + + $ ./mach lint --fix + +Not all linters support fixing, and even the ones that do can not usually fix +all types of errors. Any errors that cannot be automatically fixed, will be +printed to stdout like normal. In that case, you can also fix errors manually: + +.. parsed-literal:: + + $ ./mach lint --edit + +This requires the $EDITOR environment variable be defined. For most editors, +this will simply open each file containing errors one at a time. For vim (or +neovim), this will populate the `quickfix list`_ with the errors. + +The ``--fix`` and ``--edit`` arguments can be combined, in which case any +errors that can be fixed automatically will be, and the rest will be opened +with your $EDITOR. + +Editor Integration +================== + +.. note:: + + See details on `how to set up your editor here </contributing/editor.html#editor-ide-integration>`_ + +Editor integrations are highly recommended for linters, as they let you see +errors in real time, and can help you fix issues before you compile or run tests. + +Although mozilla-central does not currently have an integration available for +`./mach lint`, there are various integrations available for some of the major +linting tools that we use: + +* `ESLint`_ +* `Black (Python)`_ + +.. _quickfix list: http://vimdoc.sourceforge.net/htmldoc/quickfix.html +.. _ESLint: https://eslint.org/docs/user-guide/integrations#editors +.. _Black (Python): https://black.readthedocs.io/en/stable/editor_integration.html |