--- type: reference, dev stage: none group: Development info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments --- # Style guides ## Editor/IDE styling standardization We use [EditorConfig](https://editorconfig.org/) to automatically apply certain styling standards before files are saved locally. Most editors/IDEs will honor the `.editorconfig` settings automatically by default. If your editor/IDE does not automatically support `.editorconfig`, we suggest investigating to see if a plugin exists. For instance here is the [plugin for vim](https://github.com/editorconfig/editorconfig-vim). ## Pre-push static analysis with Lefthook [Lefthook](https://github.com/Arkweid/lefthook) is a Git hooks manager that allows custom logic to be executed prior to Git committing or pushing. GitLab comes with Lefthook configuration (`lefthook.yml`), but it must be installed. We have a `lefthook.yml` checked in but it is ignored until Lefthook is installed. ### Uninstall Overcommit We were using Overcommit prior to Lefthook, so you may want to uninstall it first with `overcommit --uninstall`. ### Install Lefthook 1. Install the `lefthook` Ruby gem: ```shell bundle install ``` 1. Install Lefthook managed Git hooks: ```shell bundle exec lefthook install ``` 1. Test Lefthook is working by running the Lefthook `prepare-commit-msg` Git hook: ```shell bundle exec lefthook run prepare-commit-msg ``` This should return a fully qualified path command with no other output. ### Lefthook configuration The current Lefthook configuration can be found in [`lefthook.yml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lefthook.yml). Before you push your changes, Lefthook automatically runs the following checks: - Danger: Runs a subset of checks that `danger-review` runs on your merge requests. - ES lint: Run `yarn run lint:eslint` checks (with the [`.eslintrc.yml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/.eslintrc.yml) configuration) on the modified `*.{js,vue}` files. Tags: `frontend`, `style`. - HAML lint: Run `bundle exec haml-lint` checks (with the [`.haml-lint.yml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/.haml-lint.yml) configuration) on the modified `*.html.haml` files. Tags: `view`, `haml`, `style`. - Markdown lint: Run `yarn markdownlint` checks on the modified `*.md` files. Tags: `documentation`, `style`. - SCSS lint: Run `yarn lint:stylelint` checks (with the [`.stylelintrc`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/.stylelintrc) configuration) on the modified `*.scss{,.css}` files. Tags: `stylesheet`, `css`, `style`. - RuboCop: Run `bundle exec rubocop` checks (with the [`.rubocop.yml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/.rubocop.yml) configuration) on the modified `*.rb` files. Tags: `backend`, `style`. - Vale: Run `vale` checks (with the [`.vale.ini`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/.vale.ini) configuration) on the modified `*.md` files. Tags: `documentation`, `style`. In addition to the default configuration, you can define a [local configuration](https://github.com/Arkweid/lefthook/blob/master/docs/full_guide.md#local-config). ### Disable Lefthook temporarily To disable Lefthook temporarily, you can set the `LEFTHOOK` environment variable to `0`. For instance: ```shell LEFTHOOK=0 git push ... ``` ### Run Lefthook hooks manually To run the `pre-push` Git hook, run: ```shell bundle exec lefthook run pre-push ``` For more information, check out [Lefthook documentation](https://github.com/Arkweid/lefthook/blob/master/docs/full_guide.md#run-githook-group-directly). ### Skip Lefthook checks per tag To skip some checks based on tags when pushing, you can set the `LEFTHOOK_EXCLUDE` environment variable. For instance: ```shell LEFTHOOK_EXCLUDE=frontend,documentation git push ... ``` For more information, check out [Lefthook documentation](https://github.com/Arkweid/lefthook/blob/master/docs/full_guide.md#skip-some-tags-on-the-fly). ## Ruby, Rails, RSpec Our codebase style is defined and enforced by [RuboCop](https://github.com/rubocop-hq/rubocop). You can check for any offenses locally with `bundle exec rubocop --parallel`. On the CI, this is automatically checked by the `static-analysis` jobs. For RuboCop rules that we have not taken a decision on yet, we follow the [Ruby Style Guide](https://github.com/rubocop-hq/ruby-style-guide), [Rails Style Guide](https://github.com/rubocop-hq/rails-style-guide), and [RSpec Style Guide](https://github.com/rubocop-hq/rspec-style-guide) as general guidelines to write idiomatic Ruby/Rails/RSpec, but reviewers/maintainers should be tolerant and not too pedantic about style. Similarly, some RuboCop rules are currently disabled, and for those, reviewers/maintainers must not ask authors to use one style or the other, as both are accepted. This isn't an ideal situation since this leaves space for [bike-shedding](https://en.wiktionary.org/wiki/bikeshedding), and ideally we should enable all RuboCop rules to avoid style-related discussions/nitpicking/back-and-forth in reviews. Additionally, we have a dedicated [newlines style guide](../newlines_styleguide.md), as well as dedicated [test-specific style guides and best practices](../testing_guide/index.md). ### Creating new RuboCop cops Typically it is better for the linting rules to be enforced programmatically as it reduces the aforementioned [bike-shedding](https://en.wiktionary.org/wiki/bikeshedding). To that end, we encourage creation of new RuboCop rules in the codebase. When creating a new cop that could be applied to multiple applications, we encourage you to add it to our [GitLab Styles](https://gitlab.com/gitlab-org/gitlab-styles) gem. ### Resolving RuboCop exceptions When the number of RuboCop exceptions exceed the default [`exclude-limit` of 15](https://docs.rubocop.org/rubocop/1.2/usage/basic_usage.html#command-line-flags), we may want to resolve exceptions over multiple commits. To minimize confusion, we should track our progress through the exception list. When auto-generating the `.rubocop_todo.yml` exception list for a particular Cop, and more than 15 files are affected, we should add the exception list to a different file, `.rubocop_manual_todo.yml`. This ensures that our list isn't mistakenly removed by another auto generation of the `.rubocop_todo.yml`. This also allows us greater visibility into the exceptions which are currently being resolved. One way to generate the initial list is to run the `todo` auto generation, with `exclude limit` set to a high number. ```shell bundle exec rubocop --auto-gen-config --auto-gen-only-exclude --exclude-limit=100000 ``` You can then move the list from the freshly generated `.rubocop_todo.yml` for the Cop being actively resolved and place it in the `.rubocop_manual_todo.yml`. In this scenario, do not commit auto generated changes to the `.rubocop_todo.yml` as an `exclude limit` that is higher than 15 will make the `.rubocop_todo.yml` hard to parse. ### Reveal existing RuboCop exceptions To reveal existing RuboCop exceptions in the code that have been excluded via `.rubocop_todo.yml` and `.rubocop_manual_todo.yml`, set the environment variable `REVEAL_RUBOCOP_TODO` to `1`. This allows you to reveal existing RuboCop exceptions during your daily work cycle and fix them along the way. NOTE: Permanent `Exclude`s should be defined in `.rubocop.yml` instead of `.rubocop_manual_todo.yml`. ## Database migrations See the dedicated [Database Migrations Style Guide](../migration_style_guide.md). ## JavaScript See the dedicated [JS Style Guide](../fe_guide/style/javascript.md). ## SCSS See the dedicated [SCSS Style Guide](../fe_guide/style/scss.md). ## Go See the dedicated [Go standards and style guidelines](../go_guide/index.md). ## Shell commands (Ruby) See the dedicated [Guidelines for shell commands in the GitLab codebase](../shell_commands.md). ## Shell scripting See the dedicated [Shell scripting standards and style guidelines](../shell_scripting_guide/index.md). ## Markdown We're following [Ciro Santilli's Markdown Style Guide](https://cirosantilli.com/markdown-style-guide/). ## Documentation See the dedicated [Documentation Style Guide](../documentation/styleguide/index.md). ## Python See the dedicated [Python Development Guidelines](../python_guide/index.md). ## Misc Code should be written in [US English](https://en.wikipedia.org/wiki/American_English). --- [Return to Contributing documentation](index.md)