Prevent LombokValToFinalVar from removing star imports

[Jenson3210]

Summary

• Only call maybeRemoveImport("lombok.var") when there is an explicit import lombok.var;, not from star imports like import lombok.*;
• Added tests for star import preservation with and without var usage, explicit import removal, and edge cases

Problem

Running UpgradeToJava21 on multi-module Gradle projects removes import lombok.*; wildcard imports without adding explicit replacements, breaking compilation. The reporter observed 95 files losing their star import with 0 files gaining explicit lombok imports.

The root cause is in LombokValToFinalVar which unconditionally called maybeRemoveImport("lombok.var") in visitCompilationUnit.

Solution

Changed visitCompilationUnit to check the compilation unit's import list: only call maybeRemoveImport("lombok.var") when there is an explicit import lombok.var; statement (where getQualid().getSimpleName() is not "*"). Star imports are left untouched.

Note: when import lombok.*; exists solely for var (no other lombok usage), the star import will remain as an unused import after the recipe runs. This is an acceptable trade-off—an unused import is preferable to broken compilation.

Test plan

• Existing tests pass

• preserveStarImportWithoutVarUsage — star import + annotations, no var, incomplete type info

• preserveStarImportWithVarUsage — star import + var + annotations, incomplete type info

• removeExplicitVarImport — explicit import lombok.var; removed with incomplete type info

• removeStarImportWhenOnlyValUsed — star import correctly removed when val is the only lombok usage

• starImportRemainsWhenOnlyVarUsed — star import remains unused (documented trade-off)

• Fixes UpgradeToJava21 removes import lombok.*; without adding explicit imports #962

[timtebeek]

Would this be easier perhaps than manually inspecting the imports?

Suggested change

	return super.visitCompilationUnit(compilationUnit, ctx);
	J.CompilationUnit cu = super.visitCompilationUnit(compilationUnit, ctx);
	if (cu != compilationUnit) {
	maybeRemoveImport(LOMBOK_VAR);
	}
	return cu;

[Jenson3210]

Can't do this as star imports would be removed causing the bug to reappear