A tool to enforce Swift style and conventions, loosely based on GitHub's Swift Style Guide.

SwiftLint hooks into Clang and SourceKit to use the AST representation of your source files for more accurate results.

This project adheres to the Contributor Covenant Code of Conduct. By participating, you are expected to uphold this code. Please report unacceptable behavior to info@realm.io.

Using Homebrew

brew install swiftlint 

You can also install SwiftLint by downloading SwiftLint.pkg from the latest GitHub release and running it.

You can also build from source by cloning this project and running git submodule update --init --recursive; make install (Xcode 7.1).

Integrate SwiftLint into an Xcode scheme to get warnings and errors displayed in the IDE. Just add a new "Run Script Phase" with:

if which swiftlint >/dev/null; then swiftlint else echo "warning: SwiftLint not installed, download from https://github.com/realm/SwiftLint" fi

To run swiftlint autocorrect on save in Xcode, install the SwiftLintXcode plugin from Alcatraz.

To integrate SwiftLint with Atom install the linter-swiftlint package from APM.

$ swiftlint help Available commands: autocorrect Automatically correct warnings and errors help Display general or command-specific help lint Print lint warnings and errors for the Swift files in the current directory (default command) rules Display the list of rules and their identifiers version Display the current version of SwiftLint 

Run swiftlint in the directory containing the Swift files to lint. Directories will be searched recursively.

To specify a list of files when using lint or autocorrect (like the list of files modified by Xcode specified by the ExtraBuildPhase Xcode plugin, or modified files in the working tree based on git ls-files -m) you can do so by passing the option --use-script-input-files and setting the following instance variables: SCRIPT_INPUT_FILE_COUNT and SCRIPT_INPUT_FILE_0, SCRIPT_INPUT_FILE_1... SCRIPT_INPUT_FILE_{SCRIPT_INPUT_FILE_COUNT}.

These are same environment variables set for input files to custom Xcode script phases.

There are only a small number of rules currently implemented, but we hope the Swift community (that's you!) will contribute more over time. Pull requests are encouraged.

The rules that are currently implemented are mostly there as a starting point and are subject to change.

See the Source/SwiftLintFramework/Rules directory to see the currently implemented rules.

Rules can be disabled with a comment inside a source file with the following format:

// swiftlint:disable <rule>

The rule will be disabled until the end of the file or until the linter sees a matching enable comment:

// swiftlint:enable <rule>

For example:

// swiftlint:disable colon let noWarning :String = "" // No warning about colons immediately after variable names! // swiftlint:enable colon let hasWarning :String = "" // Warning generated about colons immediately after variable names

It's also possible to modify a disable or enable command by appending :previous, :this or :next for only applying the command to the previous, this (current) or next line respectively.

For example:

// swiftlint:disable:next force_cast let noWarning = NSNumber() as! Int let hasWarning = NSNumber() as! Int let noWarning2 = NSNumber() as! Int // swiftlint:disable:this force_cast let noWarning3 = NSNumber() as! Int // swiftlint:disable:previous force_cast

Run swiftlint rules to print a list of all available rules and their identifiers.

Configure SwiftLint by adding a .swiftlint.yml file from the directory you'll run SwiftLint from. The following parameters can be configured:

Rule inclusion:

• disabled_rules: Disable rules from the default enabled set.
• opt_in_rules: Some rules are opt-in.
• whitelist_rules: Can not be specified alongside disabled_rules or opt_in_rules. Acts as a whitelist, only the rules specified in this list will be enabled.

disabled_rules: # rule identifiers to exclude from running - colon - comma - control_statement opt_in_rules: # some rules are only opt-in - empty_count - missing_docs # Find all the available rules by running: # swiftlint rules included: # paths to include during linting. `--path` is ignored if present. - Source excluded: # paths to ignore during linting. Takes precedence over `included`. - Carthage - Pods - Source/ExcludedFolder - Source/ExcludedFile.swift # configurable rules can be customized from this configuration file # binary rules can set their severity level force_cast: warning # implicitly force_try: severity: warning # explicitly # rules that have both warning and error levels, can set just the warning level # implicitly line_length: 110 # they can set both implicitly with an array type_body_length: - 300 # warning - 400 # error # or they can set both explicitly file_length: warning: 500 error: 1200 # naming rules can set warnings/errors for min_length and max_length # additionally they can set excluded names type_name: min_length: 4 # only warning max_length: # warning and error warning: 40 error: 50 excluded: iPhone # excluded via string variable_name: min_length: # only min_length error: 4 # only error excluded: # excluded via string array - id - URL - GlobalAPIKey reporter: "xcode" # reporter type (xcode, json, csv, checkstyle, junit)

You can define custom regex-based rules in you configuration file using the following syntax:

custom_rules: pirates_beat_ninjas: # rule identifier included: ".*.swift" # regex that defines paths to include during linting. optional. name: "Pirates Beat Ninjas" # rule name. optional. regex: "([n,N]inja)" # matching pattern match_kinds: # SyntaxKinds to match. optional. - comment - identifier message: "Pirates are better than ninjas." # violation message. optional. severity: error # violation severity. optional. no_hiding_in_strings: regex: "([n,N]inja)" match_kinds: string

This is what the output would look like:

You can filter the matches by providing one or more match_kinds, which will reject matches that include syntax kinds that are not present in this list. Here are all the possible syntax kinds:

• argument
• attribute.builtin
• attribute.id
• buildconfig.id
• buildconfig.keyword
• comment
• comment.mark
• comment.url
• doccomment
• doccomment.field
• identifier
• keyword
• number
• objectliteral
• parameter
• placeholder
• string
• string_interpolation_anchor
• typeidentifier

SwiftLint supports nesting configuration files for more granular control over the linting process.

• Include additional .swiftlint.yml files where necessary in your directory structure.
• Each file will be linted using the configuration file that is in its directory or at the deepest level of its parent directories. Otherwise the root configuration will be used.
• excluded and included are ignored for nested configurations.

SwiftLint can automatically correct certain violations. Files on disk are overwritten with a corrected version.

Please make sure to have backups of these files before running swiftlint autocorrect, otherwise important data may be lost.

Standard linting is disabled while correcting because of the high likelihood of violations (or their offsets) being incorrect after modifying a file while applying corrections.

MIT licensed.

SwiftLint is maintained and funded by Realm Inc. The names and logos for Realm are trademarks of Realm Inc.

We ❤️ open source software! See our other open source projects, read our blog or say hi on twitter (@realm).