0.47.1

[0.47.1] - 2022-09-07

Fixed

• Do not add trailing comma in empty parameter/argument list with comments (trailing-comma-on-call-site, trailing-comma-on-declaration-site) (#1602)
• Fix class cast exception when specifying a non-string editorconfig setting in the default ".editorconfig" (#1627)
• Fix indentation before semi-colon when it is pushed down after inserting a trailing comma (#1609)
• Do not show deprecation warning about property "disabled_rules" when using CLi-parameter --disabled-rules (#1599)
• Traversing directory hierarchy at Windows (#1600)
• Ant-style path pattern support (#1601)
• Apply @file:Suppress on all toplevel declarations (#1623)

Changed

• Display warning instead of error when no files are matched, and return with exit code 0. (#1624)

0.47.0

[0.47.0] - 2022-08-19

API Changes & RuleSet providers

If you are not an API consumer nor a RuleSet provider, then you can safely skip this section. Otherwise, please read below carefully and upgrade your usage of ktlint. In this and coming releases, we are changing and adapting important parts of our API in order to increase maintainability and flexibility for future changes. Please avoid skipping a releases as that will make it harder to migrate.

Rule lifecycle hooks / deprecate RunOnRootOnly visitor modifier

Up until ktlint 0.46 the Rule class provided only one life cycle hook. This "visit" hook was called in a depth-first-approach on all nodes in the file. A rule like the IndentationRule used the RunOnRootOnly visitor modifier to call this lifecycle hook for the root node only in combination with an alternative way of traversing the ASTNodes. Downside of this approach was that suppression of the rule on blocks inside a file was not possible (#631). More generically, this applied to all rules, applying alternative traversals of the AST.

The Rule class now offers new life cycle hooks:

• beforeFirstNode: This method is called once before the first node is visited. It can be used to initialize the state of the rule before processing of nodes starts. The ".editorconfig" properties (including overrides) are provided as parameter.
• beforeVisitChildNodes: This method is called on a node in AST before visiting its child nodes. This is repeated recursively for the child nodes resulting in a depth first traversal of the AST. This method is the equivalent of the "visit" life cycle hooks. However, note that in KtLint 0.48, the UserData of the rootnode no longer provides access to the ".editorconfig" properties. This method can be used to emit Lint Violations and to autocorrect if applicable.
• afterVisitChildNodes: This method is called on a node in AST after all its child nodes have been visited. This method can be used to emit Lint Violations and to autocorrect if applicable.
• afterLastNode: This method is called once after the last node in the AST is visited. It can be used for teardown of the state of the rule.

Optionally, a rule can stop the traversal of the remainder of the AST whenever the goal of the rule has been achieved. See KDoc on Rule class for more information.

The "visit" life cycle hook will be removed in Ktlint 0.48. In KtLint 0.47 the "visit" life cycle hook will be called only when hook "beforeVisitChildNodes" is not overridden. It is recommended to migrate to the new lifecycle hooks in KtLint 0.47. Please create an issue, in case you need additional assistence to implement the new life cycle hooks in your rules.

Ruleset providing by Custom Rule Set Provider

The KtLint engine needs a more fine-grained control on the instantiation of new Rule instances. Currently, a new instance of a rule can be created only once per file. However, when formatting files the same rule instance is reused for a second processing iteration in case a Lint violation has been autocorrected. By re-using the same rule instance, state of that rule might leak from the first to the second processing iteration.

Providers of custom rule sets have to migrate the custom rule set JAR file. The current RuleSetProvider interface which is implemented in the custom rule set is deprecated and marked for removal in KtLint 0.48. Custom rule sets using the old RuleSetProvider interface will not be run in KtLint 0.48 or above.

For now, it is advised to implement the new RuleSetProviderV2 interface without removing the old RuleSetProvider interface. In this way, KtLint 0.47 and above use the RuleSetProviderV2 interface and ignore the old RuleSetProvider interface completely. KtLint 0.46 and below only use the old RuleSetProvider interface.

Adding the new interface is straight forward, as can be seen below:

// Current implementation
public class CustomRuleSetProvider : RuleSetProvider {
    override fun get(): RuleSet = RuleSet(
        "custom",
        CustomRule1(),
        CustomRule2(),
    )
}

// New implementation
public class CustomRuleSetProvider :
    RuleSetProviderV2(CUSTOM_RULE_SET_ID),
    RuleSetProvider {
    override fun get(): RuleSet =
        RuleSet(
            CUSTOM_RULE_SET_ID,
            CustomRule1(),
            CustomRule2()
        )

    override fun getRuleProviders(): Set<RuleProvider> =
        setOf(
            RuleProvider { CustomRule1() },
            RuleProvider { CustomRule2() }
        )

    private companion object {
        const val CUSTOM_RULE_SET_ID = custom"
    }
}

Also note that file 'resource/META-INF/services/com.pinterest.ktlint.core.RuleSetProviderV2' needs to be added. In case your custom rule set provider implements both RuleSetProvider and RuleSetProviderV2, the resource directory contains files for both implementation. The content of those files is identical as the interfaces are implemented on the same class.

Once above has been implemented, rules no longer have to clean up their internal state as the KtLint rule engine can request a new instance of the Rule at any time it suspects that the internal state of the Rule is tampered with (e.g. as soon as the Rule instance is used for traversing the AST).

Rule set providing by API Consumer

The KtLint engine needs a more fine-grained control on the instantiation of new Rule instances. Currently, a new instance of a rule can be created only once per file. However, when formatting files the same rule instance is reused for a second processing iteration in case a Lint violation has been autocorrected. By re-using the same rule instance, state of that rule might leak from the first to the second processing iteration.

The ExperimentalParams parameter which is used to invoke "KtLint.lint" and "KtLint.format" contains a new parameter "ruleProviders" which will replace the "ruleSets" parameter in KtLint 0.48. Exactly one of those parameters should be a non-empty set. It is preferred that API consumers migrate to using "ruleProviders".

// Old style using "ruleSets"
KtLint.format(
    KtLint.ExperimentalParams(
        ...
        ruleSets = listOf(
            RuleSet(
                "custom",
                CustomRule1(),
                CustomRule2()
            )
        ),
        ...
    )
)

// New style using "ruleProviders"
KtLint.format(
    KtLint.ExperimentalParams(
        ...
        ruleProviders = setOf(
            RuleProvider { CustomRule1() },
            RuleProvider { CustomRule2() }
        ),
        cb = { _, _ -> }
    )
)

Once above has been implemented, rules no longer have to clean up their internal state as the KtLint rule engine can request a new instance of the Rule at any time it suspects that the internal state of the Rule is tampered with (e.g. as soon as the Rule instance is used for traversing the AST).

Format callback

The callback function provided as parameter to the format function is now called for all errors regardless whether the error has been autocorrected. Existing consumers of the format function should now explicitly check the autocorrected flag in the callback result and handle it appropriately (in most case this will be ignoring the callback results for which autocorrected has value true).

CurrentBaseline

Class com.pinterest.ktlint.core.internal.CurrentBaseline has been replaced with com.pinterest.ktlint.core.api.Baseline.

Noteworthy changes:

• Field baselineRules (nullable) is replaced with `lintErrorsPerFile (non-nullable).
• Field baselineGenerationNeeded (boolean) is replaced with status (type Baseline.Status).

The utility functions provided via com.pinterest.ktlint.core.internal.CurrentBaseline are moved to the new class. One new method List<LintError>.doesNotContain(lintError: LintError) is added.

.editorconfig property "disabled_rules"

The .editorconfig property disabled_rules (api property DefaultEditorConfigProperties.disabledRulesProperty) has been deprecated and will be removed in a future version. Use ktlint_disabled_rules (api property DefaultEditorConfigProperties.ktlintDisabledRulesProperty) instead as it more clearly identifies that ktlint is the owner of the property. This property is to be renamed in .editorconfig files and ExperimentalParams.editorConfigOverride.

Although, Ktlint 0.47.0 falls back on property disabled_rules whenever ktlint_disabled_rules is not found, this result in a warning message being printed.

Default/alternative .editorconfig

Parameter "ExperimentalParams.editorConfigPath" is deprecated in favor of the new parameter "ExperimentalParams.editorConfigDefaults". When used in the old implementation this resulted in ignoring all ".editorconfig" files on the path to the file. The new implementation uses properties from the "editorConfigDefaults"parameter only when no ".editorconfig" files on the path to the file supplies this property for the filepath.

API consumers can easily create the EditConfigDefaults by calling
"EditConfigDefaults.load(path)" or creating it programmatically.

Reload of .editorconfig file

Some API Consumers keep a long-running instance of the KtLint engine alive. In case an .editorconfig file is changed, which was already loaded into the internal cache of the KtLint engine this change would not be taken into account by KtLint. One way to deal with this, was to clear the entire KtLint cache after each change in an .editorconfig file.

Now, the API consumer can reload an .editorconfig. If the .editorconfig with given path is actually found in the cached, it will be replaced with the new value directly. If the file is not yet loaded in the cache, loading will be deferred until the file is actually requested again.

Example:

KtLint.reloadEditorConfigFile("/some/path/to/.editorconfig")

Miscellaneous

Several methods for w...

0.46.1

[0.46.1] - 2022-06-21

Minor release to address some regressions introduced in 0.46.0

Fixed

• Remove experimental flag -Xuse-k2 as it forces API Consumers to compile their projects with this same flag (#1506).
• Account for separating spaces when parsing the disabled rules (#1508).
• Do not remove space before a comment in a parameter list (#1509).
• A delegate property which starts on the same line as the property declaration should not have an extra indentation indent (#1510)

0.46.0

[0.46.0] - 2022-06-18

Promoting experimental rules to standard

The rules below are promoted from the experimental ruleset to the standard ruleset.

• annotation
• annotation-spacing
• argument-list-wrapping
• double-colon-spacing
• enum-entry-name-case
• multiline-if-else
• no-empty-first-line-in-method-block
• package-name
• trailing-comma
• spacing-around-angle-brackets
• spacing-between-declarations-with-annotations
• spacing-between-declarations-with-comments
• unary-op-spacing

Note that as a result of moving the rules that the prefix experimental: has to be removed from all references to this rule. Check references in:

• The .editorconfig setting disabled_rules.
• KtLint disable and enable directives.
• The VisitorModifier.RunAfterRule.

If your project did not run with the experimental ruleset enabled before, you might expect new lint violations to be reported. Please note that rules can be disabled via the the .editorconfig in case you do not want the rules to be applied on your project.

API Changes & RuleSet providers

If you are not an API user nor a RuleSet provider, then you can safely skip this section. Otherwise, please read below carefully and upgrade your usage of ktlint. In this and coming releases, we are changing and adapting important parts of our API in order to increase maintainability and flexibility for future changes. Please avoid skipping a releases as that will make it harder to migrate.

Lint and formatting functions

The lint and formatting changes no longer accept parameters of type Params but only ExperimentalParams. Also, the VisitorProvider parameter has been removed. Because of this, your integration with KtLint breaks. Based on feedback with ktlint 0.45.x, we now prefer to break at compile time instead of trying to keep the interface backwards compatible. Please raise an issue, in case you help to convert to the new API.

Use of ".editorconfig" properties & userData

The interface UsesEditorConfigProperties provides method getEditorConfigValue to retrieve a named .editorconfig property for a given ASTNode. When implementing this interface, the value editorConfigProperties needs to be overridden. Previously it was not checked whether a retrieved property was actually recorded in this list. Now, retrieval of unregistered properties results in an exception.

Property Ktlint.DISABLED has been removed. The property value can now be retrieved as follows:

astNode
    .getEditorConfigValue(DefaultEditorConfigProperties.disabledRulesProperty)
    .split(",")

and be supplied via the ExperimentalParams as follows:

ExperimentalParams(
    ...
    editorConfigOverride =  EditorConfigOverride.from(
      DefaultEditorConfigProperties.disabledRulesProperty to "some-rule-id,experimental:some-other-rule-id"
    )
    ...
)

Property Ktlint.ANDROID_USER_DATA_KEY has been removed. The property value can now be retrieved as follows:

astNode
    .getEditorConfigValue(DefaultEditorConfigProperties.codeStyleProperty)

and be supplied via the ExperimentalParams as follows:

ExperimentalParams(
    ...
    editorConfigOverride =  EditorConfigOverride.from(
      DefaultEditorConfigProperties.codeStyleProperty to "android" 
    )
    ...
)

This property defaults to the official Kotlin code style when not set.

Testing KtLint rules

An AssertJ style API for testing KtLint rules (#1444) has been added. Usage of this API is encouraged in favor of using the old RuleExtension API. For more information, see KtLintAssertThat API

Added

• Add experimental rule for unexpected spacing between function name and opening parenthesis (spacing-between-function-name-and-opening-parenthesis) (#1341)
• Add experimental rule for unexpected spacing in the parameter list (parameter-list-spacing) (#1341)
• Add experimental rule for incorrect spacing around the function return type (function-return-type-spacing) (#1341)
• Add experimental rule for unexpected spaces in a nullable type (nullable-type-spacing) (#1341)
• Do not add a space after the typealias name (type-parameter-list-spacing) (#1435)
• Add experimental rule for consistent spacing before the start of the function body (function-start-of-body-spacing) (#1341)
• Suppress ktlint rules using @Suppress (more information) (#765)
• Add experimental rule for rewriting the function signature (function-signature) (#1341)

Fixed

• Move disallowing blank lines in chained method calls from no-consecutive-blank-lines to new rule (no-blank-lines-in-chained-method-calls) (#1248)
• Fix check of spacing in the receiver type of an anonymous function (#1440)
• Allow comment on same line as super class in class declaration wrapping (#1457)
• Respect git hooksPath setting (#1465)
• Fix formatting of a property delegate with a dot-qualified-expression indent (#1340)
• Keep formatting of for-loop in sync with default IntelliJ formatter (indent) and a newline in the expression in a for-statement should not force to wrap it wrapping (#1350)
• Fix indentation of property getter/setter when the property has an initializer on a separate line indent (#1335)
• When .editorconfig setting indentSize is set to value tab then return the default tab width as value for indentSize (#1485)
• Allow suppressing all rules or a list of specific rules in the entire file with @file:Suppress(...) (#1029)

Changed

• Update Kotlin development version to 1.7.0 and Kotlin version to 1.7.0.
• Update shadow plugin to 7.1.2 release
• Update picocli to 4.6.3 release
• A file containing only one (non private) top level declaration (class, interface, object, type alias or function) must be named after that declaration. The name also must comply with the Pascal Case convention. The same applies to a file containing one single top level class declaration and one ore more extension functions for that class. filename (#1004)
• Promote experimental rules to standard rules set: annotation, annotation-spacing, argument-list-wrapping, double-colon-spacing, enum-entry-name-case, multiline-if-else, no-empty-first-line-in-method-block, package-name, traling-comma, spacing-around-angle-brackets, spacing-between-declarations-with-annotations, spacing-between-declarations-with-comments, unary-op-spacing (#1481)
• The CLI parameter --android can be omitted when the .editorconfig property ktlint_code_style = android is defined

0.45.2

[0.45.2] - 2022-04-06

Fixed

• Resolve compatibility issues introduced in 0.45.0 and 0.45.1 (#1434). Thanks to mateuszkwiecinski and jeremymailen for your input on this issue.

Changed

• Set Kotlin development version to 1.6.20 and Kotlin version to 1.6.20.

0.45.1

[0.45.1] - 2022-03-21

Minor release to fix a breaking issue with ktlint API consumers

Fixed

• Remove logback dependency from ktlint-core module (#1421)

0.45.0

[0.45.0] - 2022-03-18

API Changes & RuleSet providers

If you are not an API user nor a RuleSet provider, then you can safely skip this section. Otherwise, please read below carefully and upgrade your usage of ktlint. In this and coming releases, we are changing and adapting important parts of our API in order to increase maintainability and flexibility for future changes. Please avoid skipping a releases as that will make it harder to migrate.

Retrieving ".editorconfig" property value

This section is applicable when providing rules that depend on one or more values of ".editorconfig" properties. Property values should no longer be retrieved via EditConfig or directly via userData[EDITOR_CONFIG_USER_DATA_KEY]. Property values should now only be retrieved using method ASTNode.getEditorConfigValue(editorConfigProperty) of interface UsesEditorConfigProperties which is provided in this release. Starting from next release after the current release, the EditConfig and/or userData[EDITOR_CONFIG_USER_DATA_KEY] may be removed without further notice which will break your API or rule. To prevent disruption of your end user, you should migrate a.s.a.p.

Added

• Add experimental rule for unexpected spaces in a type reference before a function identifier (function-type-reference-spacing) (#1341)
• Add experimental rule for incorrect spacing after a type parameter list (type-parameter-list-spacing) (#1366)
• Add experimental rule to detect discouraged comment locations (discouraged-comment-location) (#1365)
• Add rule to check spacing after fun keyword (fun-keyword-spacing) (#1362)
• Add experimental rules for unnecessary spacing between modifiers in and after the last modifier in a modifier list (#1361)
• New experimental rule for aligning the initial stars in a block comment when present (experimental:block-comment-initial-star-alignment (#297)
• Respect .editorconfig property ij_kotlin_packages_to_use_import_on_demand (no-wildcard-imports) (#1272)
• Add new experimental rules for wrapping of block comment (comment-wrapping) (#1403)
• Add new experimental rules for wrapping of KDoc comment (kdoc-wrapping) (#1403)
• Add experimental rule for incorrect spacing after a type parameter list (type-parameter-list-spacing) (#1366)
• Expand check task to run tests on JDK 17 - "testOnJdk17"

Fixed

• Fix lint message to "Unnecessary long whitespace" (no-multi-spaces) (#1394)
• Do not remove trailing comma after a parameter of type array in an annotation (experimental:trailing-comma) (#1379)
• Do not delete blank lines in KDoc (no-trailing-spaces) (#1376)
• Do not indent raw string literals that are not followed by either trimIndent() or trimMargin() (indent) (#1375)
• Revert remove unnecessary wildcard imports as introduced in Ktlint 0.43.0 (no-unused-imports) (#1277), (#1393), (#1256)
• (Possibly) resolve memory leak (#1216)
• Initialize loglevel in Main class after parsing the CLI parameters (#1412)

Changed

• Print the rule id always in the PlainReporter (#1121)
• All wrapping logic is moved from the indent rule to the new rule wrapping (as part of the standard ruleset). In case you currently have disabled the indent rule, you may want to reconsider whether this is still necessary or that you also want to disable the new wrapping rule to keep the status quo. Both rules can be run independent of each other. (#835)

Removed

0.44.0

[0.44.0] - 2022-02-15

Please welcome paul-dingemans as an official maintainer of ktlint!

Added

• Use Gradle JVM toolchain with language version 8 to compile the project
• Basic tests for CLI (#540)
• Add experimental rule for unnecessary parentheses in function call followed by lambda (#1068)

Fixed

• Fix indentation of function literal (#1247)
• Fix false positive in rule spacing-between-declarations-with-annotations (#1281)
• Do not remove imports for same class when different alias is used (#1243)
• Fix NoSuchElementException for property accessor (trailing-comma) (#1280)
• Fix ClassCastException using ktlintFormat on class with KDoc (no-trailing-spaces) (#1270)
• Do not remove trailing comma in annotation (#1297)
• Do not remove import which is used as markdown link in KDoc only (no-unused-imports) (#1282)
• Fix indentation of secondary constructor (indent) (#1222)
• Custom gradle tasks with custom ruleset results in warning (#1269)
• Fix alignment of arrow when trailing comma is missing in when entry (trailing-comma) (#1312)
• Fix indent of delegated super type entry (indent) (#1210)
• Improve indentation of closing quotes of a multiline raw string literal (indent) (#1262)
• Trailing space should not lead to delete of indent of next line (no-trailing-spaces) (#1334)
• Force a single line function type inside a nullable type to a separate line when the max line length is exceeded (parameter-list-wrapping) (#1255)
• A single line function with a parameter having a lambda as default argument does not throw error (indent) (#1330)
• Fix executable jar on Java 16+ (#1195)
• Fix false positive unused import after autocorrecting a trailing comma (#1367)
• Fix false positive indentation (parameter-list-wrapping, argument-list-wrapping) (#897, #1045, #1119, #1255, #1267, #1319, #1320, #1337
• Force a single line function type inside a nullable type to a separate line when the max line length is exceeded (parameter-list-wrapping) (#1255)

Changed

• Update Kotlin version to 1.6.0 release
• Add separate tasks to run tests on JDK 11 - "testOnJdk11"
• Update Dokka to 1.6.0 release
• Apply ktlint experimental rules on the ktlint code base itself.
• Update shadow plugin to 7.1.1 release
• Add Kotlin-logging backed by logback as logging framework (#589)
• Update Gradle to 7.4 version

0.43.2

[0.43.2] - 2021-12-01

Minor release to fix JDK 1.8 support

Note: Please do not use the 0.43.1 release.

Fixed

• KtLint CLI 0.43 doesn't work with JDK 1.8 (#1271)

0.43.0

[0.43.0] - 2021-11-02

Added

• New trailing-comma rule (#709) (prior art by paul-dingemans)

Fixed

• Fix false positive with lambda argument and call chain (indent) (#1202)
• Fix trailing spaces not formatted inside block comments (no-trailing-spaces) (#1197)
• Do not check for .idea folder presence when using applyToIDEA globally (#1186)
• Remove spaces before primary constructor (paren-spacing) (#1207)
• Fix false positive for delegated properties with a lambda argument (indent) (#1210)
• Remove unnecessary wildcard imports (no-unused-imports) (#1256)
• Fix indentation of KDoc comment when using tab indentation style (indent) (#850)

Changed

• Support absolute paths for globs (#1131)
• Fix regression from 0.41 with argument list wrapping after dot qualified expression (argument-list-wrapping)(#1159)
• Update Gradle to 7.2 version
• Update Gradle shadow plugin to 7.1 version
• Update Kotlin version to 1.5.31 version. Default Kotlin API version was changed to 1.4!