Add OpenRewrite code cleanup with an incremental in-house runner

[vlsi]

What

Add OpenRewrite-based code cleanup (static analysis + formatting), driven by an in-house runner in build-logic/openrewrite rather than the stock org.openrewrite.rewrite Gradle plugin. Recipes are declared in config/openrewrite/rewrite.yml; rewriteRun applies them, rewriteDryRun reports a patch, rewriteDiagnose runs each recipe on its own to find failures.

Kotlin processing is off by default, so this is Java-only cleanup unless -PopenrewriteKotlin=true is passed.

Why an in-house runner instead of the stock plugin

The stock plugin was tried first (see the git history of this branch) and rebuilt as a custom runner for three reasons:

• Incremental / up-to-date. The stock rewriteDryRun re-parses the whole module on every invocation (~19s for jorphan even with no changes). The custom task declares the sources, compile classpath and config as typed inputs, so a no-change run is UP-TO-DATE in ~2s.
• Per-module isolation. Applied to the root project, the stock plugin analyses every module's sources at once, so any edit re-parses the whole tree. The custom runner registers a task per module that only sees that module's sources.
• Startup cost / OOM. Environment.scanClassLoader uses ClassGraph, which OOMs on large classpaths (Replace ClassGraph classpath scanning with ServiceLoader or something else openrewrite/rewrite#3899). The runner instead loads declarative recipes from META-INF/rewrite/*.yml on the recipe classpath and lets the referenced compiled recipes instantiate by name, and runs the work in an isolated worker.

Mixed Java/Kotlin

The 2024 blocker — the Java parser could not resolve Kotlin classes declared in the same module (JFactory.java → JEditableCheckBox.kt failed with cannot find symbol) — is gone with rewrite-gradle-plugin 7.35.0 / rewrite 8.86: the module's compiled Kotlin output is on compileClasspath, so Java sources parse with full type information.

Applying recipes to Kotlin is a separate story. Three problems were found and reported upstream; two are already fixed:

• AssertThrowsOnLastStatement throws on Kotlin test sources — fixed in Support Kotlin sources in AssertThrowsOnLastStatement openrewrite/rewrite-testing-frameworks#1048
• TypecastParenPad rewrites x as Foo into x asFoo — root cause in SpacesVisitor, fixed in Do not apply Java typecast spacing to Kotlin as casts openrewrite/rewrite#8236
• ShortenFullyQualifiedTypeReferences drops a qualifier without adding the import, and OperatorWrap moves a binary + to the start of the next line where Kotlin reads it as a unary plus — still open

Because of these, Kotlin stays off by default. With those recipes disabled the applied Kotlin compiles across the whole repository; individual recipes can be turned off by name with openrewrite.disabledRecipes or -PopenrewriteDisable=<a,b,c>.

How to run

./gradlew :src:jorphan:rewriteDryRun  -PskipOpenrewrite=false   # report a patch
./gradlew :src:jorphan:rewriteRun     -PskipOpenrewrite=false   # apply in place
./gradlew :src:jorphan:rewriteDiagnose -PskipOpenrewrite=false  # per-recipe fail/change/no-op

skipOpenrewrite defaults to true until the OpenRewrite recipe artifacts are added to gradle/verification-metadata.xml; until then the tasks also need --dependency-verification=lenient.

[vlsi]

It looks like OpenRewrite does not support mixed Java-Kotlin projects, so it can't parse Java files that call Kotlin classes:

jmeter/src/jorphan/src/main/java/org/apache/jorphan/gui/JFactory.java:111: error: cannot find symbol
    public static JEditableCheckBox small(JEditableCheckBox component) {
                  ^
  symbol:   class JEditableCheckBox
  location: class JFactory