Fix a bug in AutoAnnotation when using Collections to pass values to …

…generic array parameters. Without this AutoAnnotation would generate code that constructed arrays of generic types which would result in errors from javac like: "Cannot create a generic array of Class<? extends Annotation>" Also, change the generated code to not presize the array when calling Collection.toArray, for hotspot vms this is likely a pessimization per http://shipilev.net/blog/2016/arrays-wisdom-ancients/ and I doubt @AutoAnnotation is used much outside of hotspot vms. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=127234753
google · Aug 30, 2016 · 82041d0 · 82041d0
1 parent 5ec14eb
commit 82041d0
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Showing 4 changed files with 71 additions and 2 deletions.
diff --git a/value/src/main/java/com/google/auto/value/processor/AutoAnnotationProcessor.java b/value/src/main/java/com/google/auto/value/processor/AutoAnnotationProcessor.java
@@ -53,6 +53,7 @@
 import javax.lang.model.type.PrimitiveType;
 import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
+import javax.lang.model.type.WildcardType;
 import javax.lang.model.util.ElementFilter;
 import javax.lang.model.util.Types;
 import javax.tools.Diagnostic;
@@ -486,6 +487,34 @@ public TypeKind getKind() {
       return getTypeMirror().getKind();
     }
 
+    public boolean isArrayOfClassWithBounds() {
+      if (getTypeMirror().getKind() != TypeKind.ARRAY) {
+        return false;
+      }
+      TypeMirror componentType = ((ArrayType) getTypeMirror()).getComponentType();
+      if (componentType.getKind() != TypeKind.DECLARED) {
+        return false;
+      }
+      DeclaredType declared = (DeclaredType) componentType;
+      if (!((TypeElement) processingEnv.getTypeUtils().asElement(componentType))
+          .getQualifiedName()
+          .contentEquals("java.lang.Class")) {
+        return false;
+      }
+      if (declared.getTypeArguments().size() != 1) {
+        return false;
+      }
+      TypeMirror parameter = declared.getTypeArguments().get(0);
+      if (parameter.getKind() != TypeKind.WILDCARD) {
+        return true;  // for Class<Foo>
+      }
+      WildcardType wildcard = (WildcardType) parameter;
+      // In theory, we should check if getExtendsBound() != Object, since '?' is equivalent to
+      // '? extends Object', but, experimentally, neither javac or ecj will sets getExtendsBound()
+      // to 'Object', so there isn't a point in checking.
+      return wildcard.getSuperBound() != null || wildcard.getExtendsBound() != null;
+    }
+
     public String getDefaultValue() {
       AnnotationValue defaultValue = method.getDefaultValue();
       if (defaultValue == null) {

diff --git a/value/src/main/java/com/google/auto/value/processor/autoannotation.vm b/value/src/main/java/com/google/auto/value/processor/autoannotation.vm
@@ -67,9 +67,15 @@ final class $className implements $annotationName {
 
     this.$p = ${members[$p].typeMirror.componentType}ArrayFromCollection($p);
 
+    #elseif ($members[$p].arrayOfClassWithBounds)
+
+    @SuppressWarnings({"unchecked", "rawtypes"})
+    ${members[$p].componentType}[] ${p}$ = ${p}.toArray(new Class[0]);
+    this.$p = ${p}$;
+
     #else
 
-    this.$p = ${p}.toArray(new ${members[$p].componentType}[${p}.size()]);
+    this.$p = ${p}.toArray(new ${members[$p].componentType}[0]);
 
     #end
   #else

diff --git a/value/src/test/java/com/google/auto/value/processor/AutoAnnotationCompilationTest.java b/value/src/test/java/com/google/auto/value/processor/AutoAnnotationCompilationTest.java
@@ -285,7 +285,7 @@ public void testCollectionsForArrays() {
         "    if (enums == null) {",
         "      throw new NullPointerException(\"Null enums\");",
         "    }",
-        "    this.enums = enums.toArray(new MyEnum[enums.size()];",
+        "    this.enums = enums.toArray(new MyEnum[0];",
         "  }",
         "",
         "  @Override public Class<? extends MyAnnotation> annotationType() {",

diff --git a/value/src/test/java/com/google/auto/value/processor/AutoAnnotationErrorsTest.java b/value/src/test/java/com/google/auto/value/processor/AutoAnnotationErrorsTest.java
@@ -323,4 +323,38 @@ public void testAnnotationValuedDefaultsNotSupportedYet() {
                 + "'optionalAnnotation'")
         .in(testSource).onLine(7);
   }
+
+  public void testAnnotationMemberNameConflictWithGeneratedLocal() {
+    JavaFileObject annotationSource = JavaFileObjects.forSourceLines(
+        "com.example.TestAnnotation",
+        "package com.example;",
+        "",
+        "import java.lang.annotation.Annotation;",
+        "",
+        "public @interface TestAnnotation {",
+        "  Class<? extends Annotation>[] value();",
+        "  int value$();",
+        "}");
+    JavaFileObject testSource = JavaFileObjects.forSourceLines(
+        "com.foo.Test",
+        "package com.foo;",
+        "",
+        "import java.lang.annotation.Annotation;",
+        "import java.util.Collection;",
+        "",
+        "import com.example.TestAnnotation;",
+        "import com.google.auto.value.AutoAnnotation;",
+        "",
+        "class Test {",
+        "  @AutoAnnotation static TestAnnotation newTestAnnotation(",
+        "     Collection<Class<? extends Annotation>> value, int value$) {",
+        "    return new AutoAnnotation_Test_newTestAnnotation(value, value$);",
+        "  }",
+        "}");
+    assert_().about(javaSources())
+        .that(ImmutableList.of(annotationSource, testSource))
+        .processedWith(new AutoAnnotationProcessor())
+        .failsToCompile()
+        .withErrorContaining("variable value$ is already defined in constructor");
+  }
 }