Do not wrap operators onto a new line in Kotlin sources#936
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In Kotlin a newline terminates an expression, so a leading binary operator is
parsed as a unary operator on a new statement. With the default `WrapOption.NL`
style, `OperatorWrap` moved a binary operator to the start of the next line,
turning
val s = "aaa" + "b" +
"c"
into the uncompilable
val s = "aaa" + "b"
+ "c"
(the leading `+` becomes `unaryPlus`). This surfaced running a `CodeCleanup`
composite over Apache JMeter's mixed Java/Kotlin sources.
Restrict the visitor to `J.CompilationUnit` so it only reformats Java and leaves
Kotlin (and other non-Java `JavaSourceFile`s) untouched.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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What's changed
OperatorWrapnow only reformats Java compilation units, leaving Kotlin (and other non-JavaJavaSourceFiles) untouched. Adds a Kotlin test.Why
In Kotlin a newline terminates an expression, so a leading binary operator is parsed as a unary operator on a new statement. With the default
WrapOption.NLstyle the recipe moves a binary operator to the start of the next line:becomes
The trailing
+ "c"is now aunaryPluson a separate statement, so the code no longer compiles. This surfaced running aCodeCleanupcomposite over Apache JMeter's mixed Java/Kotlin sources — aletsPlot(...) + geomLine {...} + ...chain was broken the same way.The recipe's
visitBinarymoves operators purely by relocating whitespace, which is only valid under Java's newline rules. Restricting the visitor toJ.CompilationUnit(rather than everyJavaSourceFile) keeps the Java behaviour and stops it corrupting Kotlin.How to verify
./gradlew test --tests "*.OperatorWrapKotlinTest" --tests "*.OperatorWrapTest"— the new Kotlin test passes and the existing Java suite (19 tests) is unchanged.