Fix duplicate @Nullable annotations in AutoValue/AutoBuilder and type annotations in flag generator. Fix ConfigurableImplementationProcessor for Turbine.

value/src/it/functional/src/test/java/com/google/auto/value/AutoBuilderKotlinTest.java

@@ -408,4 +408,26 @@ public void kotlinWithTypeParameters() {
     assertThat(data.getV()).isEqualTo(2.0);
     assertThat(data.getM()).isEqualTo(map);
   }
+
+  @AutoBuilder(ofClass = KotlinDataWithNullableParameters.class)
+  interface KotlinDataWithNullableParametersBuilder<T> {
+    static <T> KotlinDataWithNullableParametersBuilder<T> builder() {
+      return new AutoBuilder_AutoBuilderKotlinTest_KotlinDataWithNullableParametersBuilder<T>();
+    }
+
+    KotlinDataWithNullableParametersBuilder<T> value(@org.jetbrains.annotations.Nullable T value);
+
+    KotlinDataWithNullableParameters<T> build();
+  }
+
+  @Test
+  public void kotlinWithNullableParameters() {
+    KotlinDataWithNullableParameters<String> x =
+        KotlinDataWithNullableParametersBuilder.<String>builder().value("hello").build();
+    assertThat(x.getValue()).isEqualTo("hello");
+
+    KotlinDataWithNullableParameters<String> nullX =
+        KotlinDataWithNullableParametersBuilder.<String>builder().value(null).build();
+    assertThat(nullX.getValue()).isNull();
+  }
 }

value/src/it/functional/src/test/java/com/google/auto/value/KotlinData.kt

@@ -102,3 +102,5 @@ data class KotlinDataWithTypeParameters<
 >(val t: T? = null, val u: U, val v: V, val m: M) {
   fun foo(w: W) {}
 }
+
+data class KotlinDataWithNullableParameters<T>(val value: T?)

value/src/main/java/com/google/auto/value/processor/AutoBuilderProcessor.java

@@ -657,7 +657,8 @@ private String findCallMethodValue(AnnotationMirror autoBuilderAnnotation) {
   }
 
   @Override
-  Optional<String> nullableAnnotationForMethod(ExecutableElement propertyMethod) {
+  Optional<String> nullableAnnotationForMethod(
+      ExecutableElement propertyMethod, AnnotatedTypeMirror propertyType) {
     // TODO(b/183005059): implement
     return Optional.empty();
   }

value/src/main/java/com/google/auto/value/processor/AutoOneOfProcessor.java

@@ -275,8 +275,9 @@ private void defineVarsForType(
   }
 
   @Override
-  Optional<String> nullableAnnotationForMethod(ExecutableElement propertyMethod) {
-    if (nullableAnnotationFor(propertyMethod, propertyMethod.getReturnType()).isPresent()) {
+  Optional<String> nullableAnnotationForMethod(
+      ExecutableElement propertyMethod, AnnotatedTypeMirror propertyType) {
+    if (nullableAnnotationFor(propertyMethod, propertyType).isPresent()) {
       errorReporter()
           .reportError(
               propertyMethod, "[AutoOneOfNullable] @AutoOneOf properties cannot be @Nullable");

value/src/main/java/com/google/auto/value/processor/AutoValueProcessor.java

@@ -514,8 +514,9 @@ private void defineVarsForType(
   }
 
   @Override
-  Optional<String> nullableAnnotationForMethod(ExecutableElement propertyMethod) {
-    return nullableAnnotationFor(propertyMethod, propertyMethod.getReturnType());
+  Optional<String> nullableAnnotationForMethod(
+      ExecutableElement propertyMethod, AnnotatedTypeMirror propertyType) {
+    return nullableAnnotationFor(propertyMethod, propertyType);
   }
 
   static ImmutableSet<ExecutableElement> prefixedGettersIn(Iterable<ExecutableElement> methods) {

value/src/main/java/com/google/auto/value/processor/AutoValueishProcessor.java

@@ -526,7 +526,8 @@ private void validateType(TypeElement type) {
    * is nullable but the <i>method</i> isn't. The {@code @Nullable} annotation will instead appear
    * when the return type of the method is spelled out in the implementation.
    */
-  abstract Optional<String> nullableAnnotationForMethod(ExecutableElement propertyMethod);
+  abstract Optional<String> nullableAnnotationForMethod(
+      ExecutableElement propertyMethod, AnnotatedTypeMirror propertyType);
 
   /**
    * Returns the ordered set of {@link Property} definitions for the given {@code @AutoValue} or
@@ -561,7 +562,8 @@ final ImmutableSet<Property> propertySet(
           ImmutableList<AnnotationMirror> methodAnnotationMirrors =
               annotatedPropertyMethods.get(propertyMethod);
           ImmutableList<String> methodAnnotations = annotationStrings(methodAnnotationMirrors);
-          Optional<String> nullableAnnotation = nullableAnnotationForMethod(propertyMethod);
+          Optional<String> nullableAnnotation =
+              nullableAnnotationForMethod(propertyMethod, returnType);
           Property p =
               new GetterProperty(
                   propertyName,
@@ -727,6 +729,13 @@ private static boolean gettersAllPrefixed(Set<ExecutableElement> methods) {
    * @param elementType the relevant type of the element: the return type for a method, or the
    *     parameter type for a parameter.
    */
+  static Optional<String> nullableAnnotationFor(Element element, AnnotatedTypeMirror elementType) {
+    if (isNullable(elementType)) {
+      return Optional.of("");
+    }
+    return nullableAnnotationFor(element, elementType.getType());
+  }
+
   static Optional<String> nullableAnnotationFor(Element element, TypeMirror elementType) {
     if (isNullable(elementType)) {
       return Optional.of("");
@@ -752,8 +761,22 @@ private static boolean isNullableAnnotation(AnnotationMirror annotation) {
     return annotation.getAnnotationType().asElement().getSimpleName().contentEquals("Nullable");
   }
 
+  private static boolean isNullable(AnnotatedTypeMirror type) {
+    return isNullable(type.getType()) || nullableAnnotationIndex(type.annotations()).isPresent();
+  }
+
   private static boolean isNullable(TypeMirror type) {
-    return nullableAnnotationIndex(type.getAnnotationMirrors()).isPresent();
+    if (nullableAnnotationIndex(type.getAnnotationMirrors()).isPresent()) {
+      return true;
+    }
+    if (type.getKind().equals(TypeKind.DECLARED)) {
+      DeclaredType declaredType = (DeclaredType) type;
+      TypeMirror enclosing = declaredType.getEnclosingType();
+      if (enclosing != null && enclosing.getKind().equals(TypeKind.DECLARED)) {
+        return isNullable(enclosing);
+      }
+    }
+    return false;
   }
 
   private static boolean isTypeVariableWithNullableBound(TypeMirror type) {
@@ -1282,14 +1305,27 @@ private ImmutableList<AnnotationMirror> propertyFieldAnnotations(
 
   private static Set<String> getReturnTypeAnnotations(
       ExecutableElement method, Predicate<TypeElement> typeFilter) {
-    return method.getReturnType().getAnnotationMirrors().stream()
+    return getAllAnnotationMirrors(method.getReturnType()).stream()
         .map(a -> a.getAnnotationType().asElement())
         .map(MoreElements::asType)
         .filter(typeFilter)
         .map(e -> e.getQualifiedName().toString())
         .collect(toSet());
   }
 
+  private static ImmutableList<AnnotationMirror> getAllAnnotationMirrors(TypeMirror type) {
+    ImmutableList.Builder<AnnotationMirror> builder = ImmutableList.builder();
+    builder.addAll(type.getAnnotationMirrors());
+    if (type.getKind().equals(TypeKind.DECLARED)) {
+      DeclaredType declaredType = (DeclaredType) type;
+      TypeMirror enclosing = declaredType.getEnclosingType();
+      if (enclosing != null && enclosing.getKind().equals(TypeKind.DECLARED)) {
+        builder.addAll(getAllAnnotationMirrors(enclosing));
+      }
+    }
+    return builder.build();
+  }
+
   private boolean annotationAppliesToFields(TypeElement annotation) {
     Target target = annotation.getAnnotation(Target.class);
     return target == null || Arrays.asList(target.value()).contains(ElementType.FIELD);

value/src/main/java/com/google/auto/value/processor/BuilderSpec.java

@@ -469,8 +469,7 @@ public static class PropertySetter {
       primitiveParameter = parameterType.getKind().isPrimitive();
       this.parameterTypeString = parameterTypeString(setter, parameterType);
       VariableElement parameterElement = Iterables.getOnlyElement(setter.getParameters());
-      Optional<String> maybeNullable =
-          nullableAnnotationFor(parameterElement, parameterType.getType());
+      Optional<String> maybeNullable = nullableAnnotationFor(parameterElement, parameterType);
       this.nullableAnnotation = maybeNullable.orElse("");
     }