ktlint
ktlint documentation
- Version in MegaLinter: 1.3.1
- Visit Official Web Site
- See Index of problems detected by ktlint
Configuration in MegaLinter
- Enable ktlint by adding
KOTLIN_KTLINT
in ENABLE_LINTERS variable - Disable ktlint by adding
KOTLIN_KTLINT
in DISABLE_LINTERS variable
- Enable autofixes by adding
KOTLIN_KTLINT
in APPLY_FIXES variable
Variable | Description | Default value |
---|---|---|
KOTLIN_KTLINT_ARGUMENTS | User custom arguments to add in linter CLI call Ex: -s --foo "bar" |
|
KOTLIN_KTLINT_COMMAND_REMOVE_ARGUMENTS | User custom arguments to remove from command line before calling the linter Ex: -s --foo "bar" |
|
KOTLIN_KTLINT_FILTER_REGEX_INCLUDE | Custom regex including filter Ex: (src\|lib) |
Include every file |
KOTLIN_KTLINT_FILTER_REGEX_EXCLUDE | Custom regex excluding filter Ex: (test\|examples) |
Exclude no file |
KOTLIN_KTLINT_CLI_LINT_MODE | Override default CLI lint mode - file : Calls the linter for each file- list_of_files : Call the linter with the list of files as argument- project : Call the linter from the root of the project |
list_of_files |
KOTLIN_KTLINT_FILE_EXTENSIONS | Allowed file extensions. "*" matches any extension, "" matches empty extension. Empty list excludes all filesEx: [".py", ""] |
[".kt", ".kts"] |
KOTLIN_KTLINT_FILE_NAMES_REGEX | File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files Ex: ["Dockerfile(-.+)?", "Jenkinsfile"] |
Include every file |
KOTLIN_KTLINT_PRE_COMMANDS | List of bash commands to run before the linter | None |
KOTLIN_KTLINT_POST_COMMANDS | List of bash commands to run after the linter | None |
KOTLIN_KTLINT_UNSECURED_ENV_VARIABLES | List of env variables explicitly not filtered before calling KOTLIN_KTLINT and its pre/post commands | None |
KOTLIN_KTLINT_DISABLE_ERRORS | Run linter but consider errors as warnings | false |
KOTLIN_KTLINT_DISABLE_ERRORS_IF_LESS_THAN | Maximum number of errors allowed | 0 |
KOTLIN_KTLINT_CLI_EXECUTABLE | Override CLI executable | ['ktlint'] |
IDE Integration
Use ktlint in your favorite IDE to catch errors before MegaLinter !
IDE | Extension Name | Install | |
---|---|---|---|
Emacs | flycheck-kotlin | Visit Web Site | |
vim | ale | Visit Web Site |
MegaLinter Flavours
This linter is available in the following flavours
Flavor | Description | Embedded linters | Info | |
---|---|---|---|---|
all | Default MegaLinter Flavor | 125 | ||
c_cpp | Optimized for pure C/C++ projects | 56 | ||
cupcake | MegaLinter for the most commonly used languages | 84 | ||
documentation | MegaLinter for documentation projects | 51 | ||
dotnet | Optimized for C, C++, C# or VB based projects | 63 | ||
dotnetweb | Optimized for C, C++, C# or VB based projects with JS/TS | 72 | ||
go | Optimized for GO based projects | 53 | ||
java | Optimized for JAVA based projects | 54 | ||
javascript | Optimized for JAVASCRIPT or TYPESCRIPT based projects | 61 | ||
php | Optimized for PHP based projects | 56 | ||
python | Optimized for PYTHON based projects | 64 | ||
ruby | Optimized for RUBY based projects | 52 | ||
rust | Optimized for RUST based projects | 52 | ||
salesforce | Optimized for Salesforce based projects | 56 | ||
swift | Optimized for SWIFT based projects | 52 | ||
terraform | Optimized for TERRAFORM based projects | 56 |
Behind the scenes
How are identified applicable files
- File extensions:
.kt
,.kts
How the linting is performed
- ktlint is called once with the list of files as arguments (
list_of_files
CLI lint mode)
Example calls
ktlint myfile.kt
ktlint --format myfile.kt
Help content
Usage: ktlint [<options>] [<arguments>]... <command> [<args>]...
An anti-bikeshedding Kotlin linter with built-in formatter. (
https://pinterest.github.io/ktlint/latest/).
Usage on Windows: java -jar ktlint.jar <options> [<arguments>]... <command>
[<args>]...
═════════════════════════════════ EXAMPLES ══════════════════════════════════
─────────────────────────── Use default patterns ────────────────────────────
Check the style of all Kotlin files (ending with '.kt' or '.kts') inside the
current dir (recursively). Hidden folders will be skipped.
ktlint
───────────────────────────── Specify patterns ──────────────────────────────
Check only certain locations starting from the current directory. Prepend !
to negate the pattern, KtLint uses .gitignore pattern style syntax. Globs are
applied starting from the last one.
Check all '.kt' files in 'src/' directory, but ignore files ending with
'Test.kt':
ktlint "src/**/*.kt" "!src/**/*Test.kt"
Check all '.kt' files in 'src/' directory, but ignore 'generated' directory
and its subdirectories:
ktlint "src/**/*.kt" "!src/**/generated/**"
─────────────────────── Auto-correct style violations ───────────────────────
Check all '.kt' files in 'src/' directory, and when possible automatically
correct the lint violations:
ktlint -F "src/**/*.kt"
───────── Using custom reporter jar and overriding report location ──────────
ktlint
--reporter=csv,artifact=/path/to/reporter/csv.jar,output=my-custom-report.csv
═══════════════════════════ Options and commands ════════════════════════════
Options:
-v, --version Show the version and exit
--code-style=(android_studio|intellij_idea|ktlint_official)
(deprecated)
--color Make output colorful
--color-name=<text> Customize the output color
-F, --format Fix deviations from the code style when possible
--limit=<int> Maximum number of errors to show (default: show all)
--relative Print files relative to the working directory (e.g.
dir/file.kt instead of
/home/user/project/dir/file.kt)
--reporter=<text> A reporter to use (built-in: plain (default),
plain?group_by_file, plain-summary, json, sarif,
checkstyle, html). To usea third-party reporter
specify a path to a JAR file on the filesystem via
',artifact=' option. To override reporter output,
use ',output=' option.
-R, --ruleset=<text> A path to a JAR file containing additional
ruleset(s)
--stdin Read file from stdin
--patterns-from-stdin[=<text>]
Read additional patterns to check/format from stdin.
Patterns are delimited by the given argument.
(default is newline). If the argument is an empty
string, the NUL byte is used.
--editorconfig=<text> Path to the default '.editorconfig'. A property
value from this file is used only when no
'.editorconfig' file on the path to the source file
specifies that property. Note: up until ktlint 0.46
the property value in this file used to override
values found in '.editorconfig' files on the path to
the source file.
--baseline=<text> Defines a baseline file to check against
-l, --log-level=<value> Defines the minimum log level (trace, debug, info,
warn, error) or none to suppress all logging
-h, --help Show this message and exit
Commands:
generateEditorConfig Generate kotlin style section for '.editorconfig'
file. Output should be copied manually to the
'.editorconfig' file.
installGitPreCommitHook Install git hook to automatically check files for
style violations on commit
installGitPrePushHook Install git hook to automatically check files for
style violations before push
Installation on mega-linter Docker image
- Dockerfile commands :
# Parent descriptor install
ENV JAVA_HOME=/usr/lib/jvm/java-21-openjdk
ENV PATH="$JAVA_HOME/bin:${PATH}"
# Linter install
RUN curl --retry 5 --retry-delay 5 -sSLO https://github.com/pinterest/ktlint/releases/latest/download/ktlint && \
chmod a+x ktlint && \
mv "ktlint" /usr/bin/