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+.
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May 28, 2026
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…34.0 to 3.36.0 [skip ci] Bumps [org.openrewrite.recipe:rewrite-migrate-java](https://github.com/openrewrite/rewrite-migrate-java) from 3.34.0 to 3.36.0. Release notes *Sourced from [org.openrewrite.recipe:rewrite-migrate-java's releases](https://github.com/openrewrite/rewrite-migrate-java/releases).* > 3.36.0 > ------ > > What's Changed > -------------- > > * Move StringFormatted recipe from Java 17 upgrade to Java best practices by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1106](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1106) > * Skip `IfElseIfConstructToSwitch` when a trailing non-`== null` binary check is present by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1109](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1109) > * Skip `UseTextBlocks` when literal value matches its source by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1111](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1111) > * Skip `UseMapOf` for `HashMap` subclasses like `LinkedHashMap` and `TreeMap` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1113](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1113) > * Skip `RenameUnderscoreIdentifier` on Kotlin and Groovy sources by [`@MBoegers`](https://github.com/MBoegers) in [openrewrite/rewrite-migrate-java#1114](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1114) > * Do not add `java.io.IO` import in `ReplaceSystemOutWithIOPrint` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1118](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1118) > * fix: do not replace lambda params with underscore when used as assignment target by [`@darrencilia`](https://github.com/darrencilia) in [openrewrite/rewrite-migrate-java#1117](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1117) > * Route WSS4J message.token classes to their real 2.x packages by [`@Jenson3210`](https://github.com/Jenson3210) in [openrewrite/rewrite-migrate-java#1122](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1122) > * Migrate `com.sun.xml.bind.marshaller.NamespacePrefixMapper` to `org.glassfish.jaxb.runtime.marshaller.NamespacePrefixMapper` by [`@Jenson3210`](https://github.com/Jenson3210) in [openrewrite/rewrite-migrate-java#1121](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1121) > * Fix `RefineSwitchCases` generating invalid guard on enum constant labels by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1124](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1124) > * Skip unparseable Java versions in FindJavaVersion instead of reporting -1 by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1125](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1125) > > New Contributors > ---------------- > > * [`@darrencilia`](https://github.com/darrencilia) made their first contribution in [openrewrite/rewrite-migrate-java#1117](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1117) > > **Full Changelog**: <openrewrite/rewrite-migrate-java@v3.35.0...v3.36.0> > > 3.35.0 > ------ > > What's Changed > -------------- > > * Add `java.io.IO` import in `ReplaceSystemOutWithIOPrint` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1093](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1093) > * Skip `UseMapOf` when `put()` argument is a null literal by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1094](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1094) > * Migrate JAXB XJC binding files declaring version 2.0/2.1/2.2 by [`@MBoegers`](https://github.com/MBoegers) in [openrewrite/rewrite-migrate-java#1098](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1098) > * Preserve explicit type arguments in MigrateCollections\* recipes by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1099](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1099) > * Route Maven through Moderne Artifactory cache to avoid HTTP 429 by [`@Jenson3210`](https://github.com/Jenson3210) in [openrewrite/rewrite-migrate-java#1096](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1096) > * Load sun.internal.new[Class].jar directly to fix CI test failures by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1101](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1101) > * Skip explicit type arguments containing wildcards in `UseVarForGenericMethodInvocations` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1102](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1102) > * Skip `var` when target type inference widens a generic argument by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1103](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1103) > * Skip `IfElseIfConstructToSwitch` when `instanceof` types are missing by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1095](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1095) > * Revert inline Maven mirror (now in gh-automation#95) by [`@Jenson3210`](https://github.com/Jenson3210) in [openrewrite/rewrite-migrate-java#1104](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1104) > * Aggregate FindJavaVersion to one row per repository by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1105](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1105) > > **Full Changelog**: <openrewrite/rewrite-migrate-java@v3.34.1...v3.35.0> > > v3.34.1 > ------- > > What's Changed > -------------- > > * OpenRewrite [v8.81.6](https://github.com/openrewrite/rewrite/releases/tag/v8.81.6) > * Refresh UpdateSdkManTest fixtures after SDKMAN CSV update by [`@steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-migrate-java#1073](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1073) > * Add more static analysis recipes to java-best-practices by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1075](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1075) > * OpenRewrite recipe best practices by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1074](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1074) > * Add jspecify hyperlink by [`@sullis`](https://github.com/sullis) in [openrewrite/rewrite-migrate-java#1076](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1076) > * Skip `var` when reassignment relies on declared supertype by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1078](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1078) > * Keep parentheses when renaming typed lambda parameter to underscore by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1082](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1082) > * Document null-probing semantic differences in singleton migrations by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1081](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1081) > * Skip main migration when referenced as static API by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1084](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1084) > * Skip `Immutable*.copyOf` rewrite when argument is not a `Collection` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1089](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1089) > * Keep block body when refined switch arm contains an if statement by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1088](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1088) ... (truncated) Commits * [`d4df178`](openrewrite/rewrite-migrate-java@d4df178) Skip unparseable Java versions in FindJavaVersion instead of reporting -1 ([#1](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1)... * [`b8a298e`](openrewrite/rewrite-migrate-java@b8a298e) Fix `RefineSwitchCases` generating invalid guard on enum constant labels ([#1124](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1124)) * [`c7f400b`](openrewrite/rewrite-migrate-java@c7f400b) [Auto] SDKMAN! Java candidates as of 2026-06-01T1550 * [`fca7c7c`](openrewrite/rewrite-migrate-java@fca7c7c) Migrate `com.sun.xml.bind.marshaller.NamespacePrefixMapper` to `org.glassfish... * [`74017b2`](openrewrite/rewrite-migrate-java@74017b2) Route WSS4J message.token classes to their real 2.x packages ([#1122](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1122)) * [`52b0808`](openrewrite/rewrite-migrate-java@52b0808) OpenRewrite recipe best practices * [`23e5804`](openrewrite/rewrite-migrate-java@23e5804) Update Gradle wrapper 9.5.1 * [`21548bd`](openrewrite/rewrite-migrate-java@21548bd) fix: do not replace lambda params with underscore when used as assignment tar... * [`61e7d90`](openrewrite/rewrite-migrate-java@61e7d90) Do not add `java.io.IO` import in `ReplaceSystemOutWithIOPrint` ([#1118](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1118)) * [`dec86d0`](openrewrite/rewrite-migrate-java@dec86d0) Skip `RenameUnderscoreIdentifier` on Kotlin and Groovy sources ([#1114](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1114)) * Additional commits viewable in [compare view](openrewrite/rewrite-migrate-java@v3.34.0...v3.36.0) [](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores) Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`. 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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.