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SwiftLint Swift style linter

Version 0.65.1 · source

SwiftLint, Postcard, light preview Light · Postcard 102 × 152 mm · PDF SwiftLint, Postcard, dark preview Dark · Postcard 102 × 152 mm · PDF SwiftLint, Postcard, ink saver preview Ink saver · Postcard 102 × 152 mm · PDF
SwiftLint, A5, light preview Light · A5 148 × 210 mm · PDF SwiftLint, A5, dark preview Dark · A5 148 × 210 mm · PDF SwiftLint, A5, ink saver preview Ink saver · A5 148 × 210 mm · PDF
SwiftLint, A4, light preview Light · A4 210 × 297 mm · PDF SwiftLint, A4, dark preview Dark · A4 210 × 297 mm · PDF SwiftLint, A4, ink saver preview Ink saver · A4 210 × 297 mm · PDF
SwiftLint, A4 landscape, light preview Light · A4 landscape 297 × 210 mm · PDF SwiftLint, A4 landscape, dark preview Dark · A4 landscape 297 × 210 mm · PDF SwiftLint, A4 landscape, ink saver preview Ink saver · A4 landscape 297 × 210 mm · PDF
SwiftLint, A3, light preview Light · A3 297 × 420 mm · PDF SwiftLint, A3, dark preview Dark · A3 297 × 420 mm · PDF SwiftLint, A3, ink saver preview Ink saver · A3 297 × 420 mm · PDF
SwiftLint, A3 landscape, light preview Light · A3 landscape 420 × 297 mm · PDF SwiftLint, A3 landscape, dark preview Dark · A3 landscape 420 × 297 mm · PDF SwiftLint, A3 landscape, ink saver preview Ink saver · A3 landscape 420 × 297 mm · PDF
SwiftLint, Letter, light preview Light · Letter 8.5 × 11 in · PDF SwiftLint, Letter, dark preview Dark · Letter 8.5 × 11 in · PDF SwiftLint, Letter, ink saver preview Ink saver · Letter 8.5 × 11 in · PDF
SwiftLint, Tabloid, light preview Light · Tabloid 11 × 17 in · PDF SwiftLint, Tabloid, dark preview Dark · Tabloid 11 × 17 in · PDF SwiftLint, Tabloid, ink saver preview Ink saver · Tabloid 11 × 17 in · PDF

Start here

swiftlint
Lint the current directory
swiftlint --fix
Auto-correct violations
swiftlint lint --strict
Treat warnings as errors
swiftlint rules
List all rules
swiftlint rules <rule>
Explain one rule
swiftlint --config <file>
Use a specific config
// swiftlint:disable:next <rule>
Silence the next line
swiftlint --reporter json
Machine-readable output

Concepts

  1. .swiftlint.yml rules + paths
  2. Swift files included minus excluded
  3. Violations warning or error
  4. Reporter xcode, json, ...

Run

swiftlint
Lint all Swift files below here
swiftlint lint <path>
Lint given files or folders
swiftlint --fix
Auto-correct what can be fixed
swiftlint lint --strict
Fail on warnings too
swiftlint lint --quiet
Print violations only
swiftlint lint --lenient
Downgrade errors to warnings
swiftlint --fix --format
Also reformat like Xcode
swiftlint lint --force-exclude <file>
Skip excluded files even if named
Needed for editor and pre-commit integrations that pass file paths explicitly.
swiftlint lint --use-stdin
Lint standard input
swiftlint lint --progress
Show a progress bar
swiftlint lint --no-cache
Ignore the lint cache
swiftlint lint --only-rule <rule>
Run just this rule
swiftlint lint --enable-all-rules
Run every rule, even opt-in
swiftlint lint --working-directory <dir>
Run as if started in <dir>
swiftlint --version
Print the version

Rules

swiftlint rules
List rules and their status
swiftlint rules <rule>
Show one rule's description
swiftlint rules --enabled
Only rules enabled by config
swiftlint rules --disabled
Only rules that are off
swiftlint rules --correctable
Only rules --fix can fix
swiftlint rules --default-config
Print every rule's defaults
swiftlint rules --config-only
Print only the YAML config
swiftlint docs
Open the rule reference
swiftlint generate-docs
Write rule docs to Markdown

Config

disabled_rules: [<rule>]
Turn off default rules
opt_in_rules: [<rule>]
Turn on extra rules
included: [Sources]
Lint only these paths
excluded: [Pods, .build]
Never lint these paths
only_rules: [<rule>]
Run exactly these rules
Cannot be combined with disabled_rules or opt_in_rules.
analyzer_rules: [<rule>]
Rules for swiftlint analyze
opt_in_rules: [all]
Enable every opt-in rule
strict: true
Warnings fail the run
reporter: "<name>"
Default output format
<rule>: warning
Set a rule's severity
line_length: 120
Warning threshold for a rule
file_length: {warning: 500, error: 1200}
Warning and error limits
type_name: {min_length: 4}
Tune a rule's options
parent_config: <path or url>
Inherit a shared config
child_config: <path or url>
Layer a higher-priority config
swiftlint --config <a> --config <b>
Stack configs, last wins
Passing --config turns off nested .swiftlint.yml lookup.
baseline: <file>
Ignore violations saved in a baseline
lenient: true
Errors become warnings

Inline control

// swiftlint:disable <rule>
Off until enabled or end of file
// swiftlint:enable <rule>
Turn the rule back on
// swiftlint:disable:next <rule>
Off for the next line
// swiftlint:disable:this <rule>
Off for this line
// swiftlint:disable:previous <r>
Off for the previous line
// swiftlint:disable all
Silence every rule
// swiftlint:disable <r1> <r2>
Several rules at once

Output

swiftlint reporters
List available reporters
swiftlint lint --reporter json
Choose the output format
swiftlint lint --reporter github-actions-logging
Annotate GitHub PRs
swiftlint lint --reporter sarif
SARIF for code scanning
swiftlint lint --reporter summary
Count violations per rule
swiftlint lint --output <file>
Write the report to a file
Common reporters
Name Use for
xcode Xcode build issues
json scripts and jq
github-actions-logging PR annotations
junit CI test reports
html browsable report
summary rule counts

Baseline & analyze

swiftlint lint --write-baseline <file>
Save current violations
swiftlint lint --baseline <file>
Report only new violations
swiftlint baseline report <file>
Show what a baseline hides
swiftlint baseline compare <a> <b>
Diff two baselines
swiftlint analyze --compiler-log-path <log>
Run analyzer rules
swiftlint analyze --fix --compiler-log-path <log>
Auto-fix analyzer rules

Install & CI

brew install swiftlint
Install with Homebrew
mint install realm/SwiftLint
Install with Mint
swift package plugin swiftlint
Run via the SwiftLintPlugins package
docker run -v $PWD:/w -w /w ghcr.io/realm/swiftlint
Run in Docker
swiftlint lint --use-script-input-files
Lint Xcode script inputs

Recipes

Minimal .swiftlint.yml
disabled_rules:  - trailing_whitespaceopt_in_rules:  - empty_count  - closure_spacingincluded:  - Sourcesexcluded:  - Podsline_length: 120type_name:  min_length: 4
Xcode run script phase
if command -v swiftlint >/dev/null 2>&1; then  swiftlintelse  echo "warning: swiftlint not installed"fi
Adopt on a messy codebase
swiftlint lint --write-baseline .swiftlint.baseline.json# then add to .swiftlint.yml:baseline: .swiftlint.baseline.jsonswiftlint lint --strict
pre-commit hook
repos:  - repo: https://github.com/realm/SwiftLint    rev: <version>    hooks:      - id: swiftlint        entry: swiftlint --fix --strict