README.md
# HAML-Lint
[](http://badge.fury.io/rb/haml_lint)
[](https://github.com/sds/haml-lint/actions/workflows/tests.yml?branch=main)
[](https://codeclimate.com/github/sds/haml-lint/maintainability)
[](https://coveralls.io/r/sds/haml-lint)
[](http://inch-ci.org/github/sds/haml-lint)
`haml-lint` is a tool to help keep your [HAML](http://haml.info) files
clean and readable. In addition to HAML-specific style and lint checks, it
integrates with [RuboCop](https://github.com/rubocop-hq/rubocop) to bring its
powerful static analysis tools to your HAML documents.
Experimental auto-correct features are also available.
You can run `haml-lint` manually from the command line, or integrate it into
your [SCM hooks](https://github.com/sds/overcommit).
* [Requirements](#requirements)
* [Installation](#installation)
* [Usage](#usage)
* [Autocorrection](#autocorrection)
* [Configuration](#configuration)
* [Linters](#linters)
* [Editor Integration](#editor-integration)
* [Git Integration](#git-integration)
* [Rake Integration](#rake-integration)
* [Documentation](#documentation)
* [Contributing](#contributing)
* [Community](#community)
* [Changelog](#changelog)
* [License](#license)
## Requirements
* Ruby 3+
* HAML 5.0+
## Installation
```bash
gem install haml_lint
```
If you'd rather install `haml-lint` using `bundler`, don't `require` it in your `Gemfile`:
```ruby
gem 'haml_lint', require: false
```
Then you can still use `haml-lint` from the command line, but its source code won't be auto-loaded inside your application.
## Usage
Run `haml-lint` from the command line by passing in a directory (or multiple
directories) to recursively scan:
```bash
haml-lint app/views/
```
You can also specify a list of files explicitly:
```bash
haml-lint app/**/*.html.haml
```
`haml-lint` will output any problems with your HAML, including the offending
filename and line number.
### File Encoding
`haml-lint` assumes all files are encoded in UTF-8.
### Command Line Flags
Command Line Flag | Description
---------------------------|----------------------------------------------------
`--auto-gen-config` | Generate a configuration file acting as a TODO list
`--auto-gen-exclude-limit` | Number of failures to allow in the TODO list before the entire rule is excluded
`--auto-gen-exclude-limit` | Number of failures to allow in the TODO list before the entire rule is excluded
`-c`/`--config` | Specify which configuration file to use
`-e`/`--exclude` | Exclude one or more files from being linted
`-i`/`--include-linter` | Specify which linters you specifically want to run
`-x`/`--exclude-linter` | Specify which linters you _don't_ want to run
`-r`/`--reporter` | Specify which reporter you want to use to generate the output
`-a`/`--auto-correct` | Enables auto-correct for safe to auto-correct lints
`-A`/`--auto-correct-all` | Enables auto-correct for unsafe and safe to auto-correct lints
`--auto-correct-only` | Only run auto-correct (in safe mode by default), uncorrectable linters are not run
`-p`/`--parallel` | Run linters in parallel using available CPUs
`--fail-fast` | Specify whether to fail after the first file with lint
`--fail-level` | Specify the minimum severity (warning or error) for which the lint should fail
`--[no-]color` | Whether to output in color
`--[no-]summary` | Whether to output a summary in the default reporter
`--show-linters` | Show all registered linters
`--show-reporters` | Display available reporters
`-s`/`--stdin FILE` | Pipe source from STDIN, using FILE in offense when combined with --auto-correct and --stdin
`--stderr` | Write all output to stderr
`-h`/`--help` | Show command line flag documentation
`-v`/`--version` | Show `haml-lint` version
`-V`/`--verbose-version` | Show `haml-lint`, `haml`, and `ruby` version information
## Autocorrection
`haml-lint` can automatically correct some of the errors that it detects. This includes
running RuboCop on the Ruby parts of your HAML templates.
* Run `haml-lint -a` to only do safe corrections (as defined by RuboCop)
* Run `haml-lint -A` to also do unsafe corrections (as defined by RuboCop)
## Configuration
`haml-lint` will automatically recognize and load any file with the name
`.haml-lint.yml` as a configuration file. It loads the configuration based on
the directory `haml-lint` is being run from, ascending until a configuration
file is found. Any configuration loaded is automatically merged with the
default configuration (see `config/default.yml`).
Here's an example configuration file:
```yaml
linters:
ImplicitDiv:
enabled: false
severity: error
LineLength:
max: 100
```
All linters have an `enabled` option which can be `true` or `false`, which
controls whether the linter is run, along with linter-specific options. The
defaults are defined in [`config/default.yml`](config/default.yml).
### Linter Options
Option | Description
--------------|----------------------------------------------------------------
`enabled` | If `false`, this linter will never be run. This takes precedence over any other option.
`include` | List of files or glob patterns to scope this linter to. This narrows down any files specified via the command line.
`exclude` | List of files or glob patterns to exclude from this linter. This excludes any files specified via the command line or already filtered via the `include` option.
`severity` | The severity of the linter. External tools consuming `haml-lint` output can use this to determine whether to warn or error based on the lints reported.
### Global File Exclusion
The `exclude` global configuration option allows you to specify a list of files
or glob patterns to exclude from all linters. This is useful for ignoring
third-party code that you don't maintain or care to lint. You can specify a
single string or a list of strings for this option.
### Skipping Frontmatter
Some static blog generators such as [Jekyll](http://jekyllrb.com/) include
leading frontmatter to the template for their own tracking purposes.
`haml-lint` allows you to ignore these headers by specifying the
`skip_frontmatter` option in your `.haml-lint.yml` configuration:
```yaml
skip_frontmatter: true
```
### Inheriting from Other Configuration Files
The `inherits_from` global configuration option allows you to specify an
inheritance chain for a configuration file. It accepts either a scalar value of
a single file name or a vector of multiple files to inherit from. The inherited
files are resolved in a first in, first out order and with "last one wins"
precedence. For example:
```yaml
inherits_from:
- .shared_haml-lint.yml
- .personal_haml-lint.yml
```
First, the default configuration is loaded. Then the `.shared_haml-lint.yml`
configuration is loaded, followed by `.personal_haml-lint.yml`. Each of these
overwrite each other in the event of a collision in configuration value. Once
the inheritance chain is resolved, the base configuration is loaded and applies
its rules to overwrite any in the intermediate configuration.
Lastly, in order to match your RuboCop configuration style, you can also use the
`inherit_from` directive, which is an alias for `inherits_from`.
## Linters
### [ยป Linters Documentation](lib/haml_lint/linter/README.md)
`haml-lint` is an opinionated tool that helps you enforce a consistent style in
your HAML files. As an opinionated tool, we've had to make calls about what we
think are the "best" style conventions, even when there are often reasonable
arguments for more than one possible style. While all of our choices have a
rational basis, we think that the opinions themselves are less important than
the fact that `haml-lint` provides us with an automated and low-cost means of
enforcing consistency.
### Custom Linters
Add the following to your configuration file:
```yaml
require:
- './relative/path/to/my_first_linter.rb'
- 'absolute/path/to/my_second_linter.rb'
```
The files that are referenced by this config should have the following structure:
```ruby
module HamlLint
# MyFirstLinter is the name of the linter in this example, but it can be anything
class Linter::MyFirstLinter < Linter
include LinterRegistry
def visit_tag
return unless node.tag_name == 'div'
record_lint(node, "You're not allowed divs!")
end
end
end
```
For more information on the different types on HAML node, please look through
the HAML parser code: https://github.com/haml/haml/blob/master/lib/haml/parser.rb
Keep in mind that by default your linter will be disabled by default. So you
will need to enable it in your configuration file to have it run.
## Disabling Linters within Source Code
One or more individual linters can be disabled locally in a file by adding
a directive comment. These comments look like the following:
```haml
-# haml-lint:disable AltText, LineLength
[...]
-# haml-lint:enable AltText, LineLength
```
You can disable *all* linters for a section with the following:
```haml
-# haml-lint:disable all
```
### Directive Scope
A directive will disable the given linters for the scope of the block. This
scope is inherited by child elements and sibling elements that come after the
comment. For example:
```haml
-# haml-lint:disable AltText
#content
%img#will-not-show-lint-1{ src: "will-not-show-lint-1.png" }
-# haml-lint:enable AltText
%img#will-show-lint-1{ src: "will-show-lint-1.png" }
.sidebar
%img#will-show-lint-2{ src: "will-show-lint-2.png" }
%img#will-not-show-lint-2{ src: "will-not-show-lint-2.png" }
```
The `#will-not-show-lint-1` image on line 2 will not raise an `AltText` lint
because of the directive on line 1. Since that directive is at the top level of
the tree, it applies everywhere.
However, on line 4, the directive enables the `AltText` linter for the remainder
of the `#content` element's content. This means that the `#will-show-lint-1`
image on line 5 will raise an `AltText` lint because it is a sibling of the
enabling directive that appears later in the `#content` element. Likewise, the
`#will-show-lint-2` image on line 7 will raise an `AltText` lint because it is
a child of a sibling of the enabling directive.
Lastly, the `#will-not-show-lint-2` image on line 8 will not raise an `AltText`
lint because the enabling directive on line 4 exists in a separate element and
is not a sibling of the it.
### Directive Precedence
If there are multiple directives for the same linter in an element, the last
directive wins. For example:
```haml
-# haml-lint:enable AltText
%p Hello, world!
-# haml-lint:disable AltText
%img#will-not-show-lint{ src: "will-not-show-lint.png" }
```
There are two conflicting directives for the `AltText` linter. The first one
enables it, but the second one disables it. Since the disable directive came
later, the `#will-not-show-lint` element will not raise an `AltText` lint.
You can use this functionality to selectively enable directives within a file by
first using the `haml-lint:disable all` directive to disable all linters in the
file, then selectively using `haml-lint:enable` to enable linters one at a time.
## Onboarding Onto a Preexisting Project
Adding a new linter into a project that wasn't previously using one can be
a daunting task. To help ease the pain of starting to use Haml-Lint, you can
generate a configuration file that will exclude all linters from reporting lint
in files that currently have lint. This gives you something similar to a to-do
list where the violations that you had when you started using Haml-Lint are
listed for you to whittle away, but ensuring that any views you create going
forward are properly linted.
To use this functionality, call Haml-Lint like:
haml-lint --auto-gen-config
This will generate a `.haml-lint_todo.yml` file that contains all existing lint
as exclusions. You can then add `inherits_from: .haml-lint_todo.yml` to your
`.haml-lint.yml` configuration file to ensure these exclusions are used whenever
you call `haml-lint`.
By default, any rules with more than 15 violations will be disabled in the todo-file.
You can increase this limit with the `auto-gen-exclude-limit` option:
haml-lint --auto-gen-config --auto-gen-exclude-limit 100
## Editor Integration
### Vim
If you use `vim`, you can have `haml-lint` automatically run against your HAML
files after saving by using the
[Syntastic](https://github.com/scrooloose/syntastic) plugin. If you already
have the plugin, just add `let g:syntastic_haml_checkers = ['haml_lint']` to
your `.vimrc`.
### Vim 8 / Neovim
If you use `vim` 8+ or `Neovim`, you can have `haml-lint` automatically run against your HAML files as you type by using the [Asynchronous Lint Engine (ALE)](https://github.com/w0rp/ale) plugin. ALE will automatically lint your HAML files if it detects `haml-lint` in your `PATH`.
### Sublime Text 3
If you use `SublimeLinter 3` with `Sublime Text 3` you can install the
[SublimeLinter-haml-lint](https://github.com/jeroenj/SublimeLinter-contrib-haml-lint)
plugin using [Package Control](https://sublime.wbond.net).
### Atom
If you use `atom`, you can install the [linter-haml](https://atom.io/packages/linter-haml) plugin.
### TextMate 2
If you use `TextMate 2`, you can install the [Haml-Lint.tmbundle](https://github.com/jjuliano/Haml-Lint.tmbundle) bundle.
### Visual Studio Code
If you use `Visual Studio Code`, you can install the [Haml Lint](https://marketplace.visualstudio.com/items?itemName=aki77.haml-lint) extension
### RubyMine
If you use `RubyMine`, you can install the [HamlLint](https://plugins.jetbrains.com/plugin/21585-hamllint) plugin.
## Git Integration
If you'd like to integrate `haml-lint` into your Git workflow, check out our
Git hook manager, [overcommit](https://github.com/sds/overcommit).
## Rake Integration
To execute `haml-lint` via a [Rake](https://github.com/ruby/rake) task, make
sure you have `rake` included in your gem path (e.g. via `Gemfile`) add the
following to your `Rakefile`:
```ruby
require 'haml_lint/rake_task'
HamlLint::RakeTask.new
```
By default, when you execute `rake haml_lint`, the above configuration is
equivalent to running `haml-lint .`, which will lint all `.haml` files in the
current directory and its descendants.
You can customize your task by writing:
```ruby
require 'haml_lint/rake_task'
HamlLint::RakeTask.new do |t|
t.config = 'custom/config.yml'
t.files = ['app/views', 'custom/*.haml']
t.quiet = true # Don't display output from haml-lint to STDOUT
end
```
You can also use this custom configuration with a set of files specified via
the command line:
```
# Single quotes prevent shell glob expansion
rake 'haml_lint[app/views, custom/*.haml]'
```
Files specified in this manner take precedence over the task's `files`
attribute.
## Documentation
[Code documentation] is generated with [YARD] and hosted by [RubyDoc.info].
[Code documentation]: http://rdoc.info/github/sds/haml-lint/master/frames
[YARD]: http://yardoc.org/
[RubyDoc.info]: http://rdoc.info/
## Contributing
We love getting feedback with or without pull requests. If you do add a new
feature, please add tests so that we can avoid breaking it in the future.
Speaking of tests, we use [Appraisal] to test against both HAML 4 and 5. We use
`rspec` to write our tests. To run the test suite, execute the following from
the root directory of the repository:
```bash
appraisal bundle install
appraisal bundle exec rspec
```
To run the test suite faster (about 4x), you can skip the RuboCop invocations for testing
auto-correct with this command:
```bash
STUB_RUBOCOP=true appraisal bundle exec rspec
```
[Appraisal]: https://github.com/thoughtbot/appraisal
## Community
All major discussion surrounding HAML-Lint happens on the
[GitHub issues page](https://github.com/sds/haml-lint/issues).
## Changelog
If you're interested in seeing the changes and bug fixes between each version
of `haml-lint`, read the [HAML-Lint Changelog](CHANGELOG.md).
## License
This project is released under the [MIT license](MIT-LICENSE).