Skip RenameUnderscoreIdentifier on Kotlin and Groovy sources#1114
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Mirror the precondition gate already used by the sibling `ReplaceUnusedVariablesWithUnderscore` so the recipe no longer rewrites legal `_` placeholders in Kotlin lambdas to `__`, which is reserved in Kotlin 2.0+.
timtebeek
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May 28, 2026
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Summary
RenameUnderscoreIdentifier's only precondition wasUsesJavaVersion<>(1, 8). In polyglot projects whose Kotlin sources target Java 8 bytecode, the recipe visited Kotlin lambdas and rewrote legal_placeholder parameters to__, which is reserved in Kotlin 2.0+ (e.g.{ _, _ -> ... }became{ __, __ -> ... }, producing two compile errors per site).Add
Preconditions.not(new KotlinFileChecker<>())andPreconditions.not(new GroovyFileChecker<>())to the precondition, mirroring the gate already present on the siblingReplaceUnusedVariablesWithUnderscorerecipe.Add a regression test (
kotlinFileNotChanged) asserting a Java-8-marked Kotlin source containing{ _, _ -> ... }is left untouched.Resolves moderneinc/customer-requests#2449.
Test plan
./gradlew test --tests 'org.openrewrite.java.migrate.lang.RenameUnderscoreIdentifierTest'passes, including the new Kotlin regression.