pinterest/ktlint 0.50.0

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Deprecation of ktlint-enable and ktlint-disable directives

The ktlint-disable and ktlint-enable directives are no longer supported. Ktlint rules can now only be suppressed using the @Suppress or @SuppressWarnings annotations. A new rule, internal:ktlint-suppression, is provided to replace the directives with annotations.

API consumers do not need to provide this rule, but it does no harm when done.

The internal:ktlint-suppression rule can not be disabled via the .editorconfig nor via @Suppress or @SuppressWarnings annotations.

Custom Rule Providers need to prepare for Kotlin 1.9

In Kotlin 1.9 the extension points of the embedded kotlin compiler will change. Ktlint only uses the org.jetbrains.kotlin.com.intellij.treeCopyHandler extension point. This extension is not yet supported in 1.9, neither is it documented (#KT-58704). Without this extension point it might happen that your custom rules will throw exceptions during runtime. See #1981.

In Ktlint, 7 out of 77 rules needed small and sometimes bigger changes to become independent of the extension point org.jetbrains.kotlin.com.intellij.treeCopyHandler. The impact on your custom rules may vary dependent on the way the autocorrect has been implemented. When manipulating ASTNodes there seems to be no impact. When, manipulating PsiElements, some functions consistently result in a runtime exception.

Based on the refactoring of the rules as provided by ktlint-ruleset-standard in Ktlint 0.49.x the suggested refactoring is as follows:

• Replace LeafElement.replaceWithText(String) with LeafElement.rawReplaceWithText(String).
• Replace PsiElement.addAfter(PsiElement, PsiElement) with AstNode.addChild(AstNode, AstNode). Note that this method inserts the new node (first) argument before the second argument node and as of that is not a simple replacement of the PsiElement.addAfter(PsiElement, PsiElement).
• Replace PsiElement.replace(PsiElement) with a sequence of AstNode.addChild(AstNode, AstNode) and AstNode.removeChild(AstNode).

Be aware that your custom rules might use other functions which also throw exceptions when the extension point org.jetbrains.kotlin.com.intellij.treeCopyHandler is no longer supported.

In order to help you to analyse and fix the problems with your custom rules, ktlint temporarily supports to disable the extension point org.jetbrains.kotlin.com.intellij.treeCopyHandler using a flag. This flag is available in the Ktlint CLI and in the KtlintRuleEngine. By default, the extension point is enabled like it was in previous versions of ktlint.

At least you should analyse the problems by running your test suits by running ktlint and disabling the extension point. Next you can start with fixing and releasing the updated rules. All rules in this version of ktlint have already been refactored and are not dependent on the extension point anymore. In Ktlint CLI the flag is to be activated with parameter --disable-kotlin-extension-point. API Consumers that use the KtlintRuleEngine directly, have to set property enableKotlinCompilerExtensionPoint to false.

At this point in time, it is not yet decided what the next steps will be. Ktlint might drop the support of the extension points entirely. Or, if the extension point org.jetbrains.kotlin.com.intellij.treeCopyHandler is fully supported at the time that ktlint will be based on kotlin 1.9 it might be kept. In either case, the flag will be dropped in a next version of ktlint.

Added

• Add new experimental rule binary-expression-wrapping. This rule wraps a binary expression in case the max line length is exceeded (#1940)
• Add flag to disable extension point org.jetbrains.kotlin.com.intellij.treeCopyHandler to analyse impact on custom rules #1981
• Add new experimental rule no-empty-file for all code styles. A kotlin (script) file may not be empty (#1074)
• Add new experimental rule statement-wrapping which ensures function, class, or other blocks statement body doesn't start or end at starting or ending braces of the block (#1938)
• Add new experimental rule blank-line-before-declaration. This rule requires a blank line before class, function or property declarations (#1939)
• Wrap multiple statements on same line wrapping (#1078)
• Add new rule ktlint-suppression to replace the ktlint-disable and ktlint-enable directives with annotations. This rule can not be disabled via the .editorconfig (#1947)
• Inform user about using --format option of KtLint CLI when finding a violation that can be autocorrected (#1071)

Removed

• Code which was deprecated in 0.49.x is removed. Consult changelog of 0.49.x` released for more information. Summary of removed code:

Fixed

• Do not flag a (potential) mutable extension property in case the getter is annotated or prefixed with a modifier property-naming (#2024)
• Do not merge an annotated expression body with the function signature even if it fits on a single line (#2043)
• Ignore property with name serialVersionUID in property-naming (#2045)
• Prevent incorrect reporting of violations in case a nullable function type reference exceeds the maximum line length parameter-list-wrapping (#1324)
• Prevent false negative on else branch when body contains only chained calls or binary expression (#2057)
• Fix indent when property value is wrapped to next line (#2095)

Changed

• Fix Java interoperability issues with RuleId and RuleSetId classes. Those classes were defined as value classes in 0.49.0 and 0.49.1. Although the classes were marked with @JvmInline it seems that it is not possible to uses those classes from Java base API Consumers like Spotless. The classes have now been replaced with data classes (#2041)
• Update dependency info.picocli:picocli to v4.7.4
• Update dependency org.junit.jupiter:junit-jupiter to v5.9.3
• Update Kotlin development version to 1.8.22 and Kotlin version to 1.8.22.
• Update dependency io.github.detekt.sarif4k:sarif4k to v0.4.0
• Update dependency org.jetbrains.dokka:dokka-gradle-plugin to v1.8.20
• Run format up to 3 times in case formatting introduces changes which also can be autocorrected (#2084)