Keep MockUtil declarations used across files and switch labels

[martinfrancois]

Suggested review order: 50 of 52 (Score: 1)
Review first: openrewrite/rewrite-migrate-java#1197

What's changed?

Adds 2 known-failing tests to MockUtilsToStaticTest that reproduce two defects in MockUtilsToStatic: the recipe removes a MockUtil field that another source file still uses, and it never removes a fully migrated MockUtil declaration that sits directly under a case label. No recipe code changes. The tests are marked @Disabled so the suite stays green; removing the annotation shows the failures. The class had 3 tests on main and has 5 with this change; the 3 pre-existing tests still pass.

What's your motivation?

Recipe: org.openrewrite.java.testing.mockito.MockUtilsToStatic.

Case 1: cross-file field use

Before

The recipe decides per file whether a MockUtil variable is still needed. It never sees uses from other compilation units. Given these two files in one run:

package mockito.example;

import org.mockito.internal.util.MockUtil;

public class MockitoMockUtils {
    public MockUtil util = new MockUtil();
}

package mockito.example;

public class MockitoMockUtilsUser {
    public boolean isMockUtilSet(MockitoMockUtils utils) {
        return utils.util != null;
    }
}

Actual after the recipe

Using current main. the first file becomes an empty class, public class MockitoMockUtils {\n}, with the field and the import removed. The second file is unchanged and still reads utils.util. Compiling the output pair with javac fails with:

error: cannot find symbol
  symbol:   variable util
  location: variable utils of type MockitoMockUtils

After the recipe runs, the code should still compile, so the field should stay when another file uses it. Test: doNotRemoveFieldUsedInAnotherClass.

Expected after the recipe

(unchanged)

Case 2: declaration under a case label

Before

Given an old-style switch:

switch (mode) {
    case 1:
        MockUtil util = new MockUtil();
        return util.isMock(value);
    default:
        return false;
}

Actual after the recipe

Using current main, the call is migrated to MockUtil.isMock(value), but the now-unused MockUtil util = new MockUtil(); line stays. The DeleteStatement scheduled from visitNewClass only removes statements whose parent is a J.Block; statements after case 1: hang off the J.Case instead, so the dead declaration is left behind. Test: mockUtilsVariableInSwitchCaseToStatic.

Expected after the recipe

The call MUST be migrated and the unused declaration MUST be removed.

Found while preparing #1084, which rewrites the removal logic in this recipe but deliberately does not fix these two behaviors, as its description discloses.

Anything in particular you'd like reviewers to focus on?

I think defect 1 is a genuine bug, because the recipe produces code that does not compile. Defect 2 is more of an improvement: the output compiles, it just keeps a dead statement. If you agree this should change, I would gladly prepare the fix. If this behavior is intended, feel free to close this and I know it is settled.

Any additional context

Pre-existing tests changed: None.

Related open PR of mine touching the same recipe: #1084. It does not fix either behavior here; its removal logic also handles only declarations whose parent is a block, so the case-label gap persists with it.

This reproduction was prepared with AI assistance (Claude Code). I reviewed the tests and this description.

The added reproduction tests and the existing suite together cover changed and unchanged behavior. The known-failing tests remain disabled until implementation. The formatter run was calibrated per file; untouched lines were not reformatted.

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've run ./gradlew build locally, and committed any resulting changes to recipes.csv
• I've formatted the lines I changed, without reformatting code I didn't touch