UnusedMethod: pioneer a list of exempting class annotations in orde…

…r to exempt methods on `AnnotationsToApply` classes. PiperOrigin-RevId: 564371793
google · Sep 15, 2023 · 65d26d8 · 65d26d8
1 parent 5c391b4
commit 65d26d8
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Showing 2 changed files with 22 additions and 1 deletion.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/UnusedMethod.java b/core/src/main/java/com/google/errorprone/bugpatterns/UnusedMethod.java
@@ -31,6 +31,7 @@
 import static com.google.errorprone.util.ASTHelpers.canBeRemoved;
 import static com.google.errorprone.util.ASTHelpers.getSymbol;
 import static com.google.errorprone.util.ASTHelpers.getType;
+import static com.google.errorprone.util.ASTHelpers.hasAnnotation;
 import static com.google.errorprone.util.ASTHelpers.isGeneratedConstructor;
 import static com.google.errorprone.util.ASTHelpers.isSubtype;
 import static com.google.errorprone.util.ASTHelpers.scope;
@@ -150,6 +151,10 @@ public final class UnusedMethod extends BugChecker implements CompilationUnitTre
           "org.junit.jupiter.api.Test",
           "org.junit.jupiter.params.ParameterizedTest");
 
+  /** Class annotations which exempt methods within the annotated class from findings. */
+  private static final ImmutableSet<String> EXEMPTING_CLASS_ANNOTATIONS =
+      ImmutableSet.of("com.google.auto.factory.AutoFactory.AnnotationsToApply");
+
   /** The set of types exempting a type that is extending or implementing them. */
   private static final ImmutableSet<String> EXEMPTING_SUPER_TYPES = ImmutableSet.of();
 
@@ -188,7 +193,8 @@ class MethodFinder extends SuppressibleTreePathScanner<Void, Void> {
 
       @Override
       public Void visitClass(ClassTree tree, Void unused) {
-        if (exemptedBySuperType(getType(tree), state)) {
+        if (exemptedBySuperType(getType(tree), state)
+            || EXEMPTING_CLASS_ANNOTATIONS.stream().anyMatch(a -> hasAnnotation(tree, a, state))) {
           return null;
         }
         return super.visitClass(tree, null);

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/UnusedMethodTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/UnusedMethodTest.java
@@ -513,4 +513,19 @@ public void effectivelyPrivateMethodMadeVisible_bySubclassImplementingPublicInte
             "}")
         .doTest();
   }
+
+  @Test
+  public void methodExemptedByClassAnnotation() {
+    helper
+        .addSourceLines(
+            "Test.java",
+            "import com.google.errorprone.annotations.ThreadSafe;",
+            "class Test {",
+            "  @com.google.auto.factory.AutoFactory.AnnotationsToApply",
+            "  private @interface AutoFactoryThreadSafe {",
+            "    ThreadSafe threadSafe() default @ThreadSafe;",
+            "  }",
+            "}")
+        .doTest();
+  }
 }