Copy annotations from `@AutoValue.Builder` to the generated `Builder` subclass.

This happens only if `@AutoValue.CopyAnnotations` is present on the `@AutoValue.Builder` class, using the same logic as for copying annotations from the main `@AutoValue` class.

RELNOTES=Optionally copy annotations from the `@AutoValue.Builder` class to the generated subclass.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=315291023

8 files changed, 88 insertions, 16 deletions

diff --git a/value/src/it/functional/src/test/java/com/google/auto/value/AutoValueTest.java b/value/src/it/functional/src/test/java/com/google/auto/value/AutoValueTest.java
index 3a024ab1..346bc53a 100644
--- a/value/src/it/functional/src/test/java/com/google/auto/value/AutoValueTest.java
+++ b/value/src/it/functional/src/test/java/com/google/auto/value/AutoValueTest.java
@@ -1056,6 +1056,11 @@ public class AutoValueTest {
     String value();
   }
 
+  @AutoAnnotation
+  private static MyAnnotation myAnnotation(String value) {
+    return new AutoAnnotation_AutoValueTest_myAnnotation(value);
+  }
+
   @AutoValue
   abstract static class PrimitiveArrays {
     @SuppressWarnings("mutable")
@@ -3365,4 +3370,51 @@ public class AutoValueTest {
             .getGenericParameterTypes()[0];
     assertThat(generatedBuilderParamType).isEqualTo(originalReturnType);
   }
+
+  @AutoValue
+  abstract static class BuilderAnnotationsNotCopied {
+    abstract String foo();
+
+    static Builder builder() {
+      return new AutoValue_AutoValueTest_BuilderAnnotationsNotCopied.Builder();
+    }
+
+    @AutoValue.Builder
+    @MyAnnotation("thing")
+    abstract static class Builder {
+      abstract Builder setFoo(String x);
+      abstract BuilderAnnotationsNotCopied build();
+    }
+  }
+
+  @Test
+  public void builderAnnotationsNotCopiedByDefault() {
+    BuilderAnnotationsNotCopied.Builder builder = BuilderAnnotationsNotCopied.builder();
+    assertThat(builder.getClass().getAnnotations()).isEmpty();
+    assertThat(builder.setFoo("foo").build().foo()).isEqualTo("foo");
+  }
+
+  @AutoValue
+  abstract static class BuilderAnnotationsCopied {
+    abstract String foo();
+
+    static Builder builder() {
+      return new AutoValue_AutoValueTest_BuilderAnnotationsCopied.Builder();
+    }
+
+    @AutoValue.Builder
+    @AutoValue.CopyAnnotations
+    @MyAnnotation("thing")
+    abstract static class Builder {
+      abstract Builder setFoo(String x);
+      abstract BuilderAnnotationsCopied build();
+    }
+  }
+
+  @Test
+  public void builderAnnotationsCopiedIfRequested() {
+    BuilderAnnotationsCopied.Builder builder = BuilderAnnotationsCopied.builder();
+    assertThat(builder.getClass().getAnnotations()).asList().containsExactly(myAnnotation("thing"));
+    assertThat(builder.setFoo("foo").build().foo()).isEqualTo("foo");
+  }
 }
diff --git a/value/src/main/java/com/google/auto/value/processor/AutoValueOrOneOfProcessor.java b/value/src/main/java/com/google/auto/value/processor/AutoValueOrOneOfProcessor.java
index 494577a5..6e708ba0 100644
--- a/value/src/main/java/com/google/auto/value/processor/AutoValueOrOneOfProcessor.java
+++ b/value/src/main/java/com/google/auto/value/processor/AutoValueOrOneOfProcessor.java
@@ -873,7 +873,7 @@ abstract class AutoValueOrOneOfProcessor extends AbstractProcessor {
     return className.startsWith(AUTO_VALUE_PACKAGE_NAME) && !className.contains("Test");
   }
 
-  private ImmutableList<String> copiedClassAnnotations(TypeElement type) {
+  ImmutableList<String> copiedClassAnnotations(TypeElement type) {
     // Only copy annotations from a class if it has @AutoValue.CopyAnnotations.
     if (hasAnnotationMirror(type, COPY_ANNOTATIONS_NAME)) {
       Set<String> excludedAnnotations =
diff --git a/value/src/main/java/com/google/auto/value/processor/AutoValueOrOneOfTemplateVars.java b/value/src/main/java/com/google/auto/value/processor/AutoValueOrOneOfTemplateVars.java
index 9ad7d043..9fdbea4f 100644
--- a/value/src/main/java/com/google/auto/value/processor/AutoValueOrOneOfTemplateVars.java
+++ b/value/src/main/java/com/google/auto/value/processor/AutoValueOrOneOfTemplateVars.java
@@ -56,9 +56,10 @@ abstract class AutoValueOrOneOfTemplateVars extends TemplateVars {
   String simpleClassName;
 
   /**
-   * The full spelling of any annotation to add to this class, or an empty list if there are none. A
-   * non-empty value might look something like {@code
-   * "@com.google.common.annotations.GwtCompatible(serializable = true)"}.
+   * The full spelling of any annotations to add to this class, or an empty list if there are none.
+   * A non-empty value might look something like {@code
+   * "@`com.google.common.annotations.GwtCompatible`(serializable = true)"}. The {@code ``} marks
+   * are explained in {@link TypeEncoder}.
    */
   ImmutableList<String> annotations;
 
diff --git a/value/src/main/java/com/google/auto/value/processor/AutoValueProcessor.java b/value/src/main/java/com/google/auto/value/processor/AutoValueProcessor.java
index a469d566..cbdc7734 100644
--- a/value/src/main/java/com/google/auto/value/processor/AutoValueProcessor.java
+++ b/value/src/main/java/com/google/auto/value/processor/AutoValueProcessor.java
@@ -423,7 +423,7 @@ public class AutoValueProcessor extends AutoValueOrOneOfProcessor {
       AutoValueTemplateVars vars,
       ImmutableSet<ExecutableElement> toBuilderMethods,
       ImmutableMap<ExecutableElement, TypeMirror> propertyMethodsAndTypes,
-      Optional<BuilderSpec.Builder> builder) {
+      Optional<BuilderSpec.Builder> maybeBuilder) {
     ImmutableSet<ExecutableElement> propertyMethods = propertyMethodsAndTypes.keySet();
     // We can't use ImmutableList.toImmutableList() for obscure Google-internal reasons.
     vars.toBuilderMethods =
@@ -436,11 +436,13 @@ public class AutoValueProcessor extends AutoValueOrOneOfProcessor {
         propertySet(propertyMethodsAndTypes, annotatedPropertyFields, annotatedPropertyMethods);
     vars.serialVersionUID = getSerialVersionUID(type);
     // Check for @AutoValue.Builder and add appropriate variables if it is present.
-    if (builder.isPresent()) {
-      ImmutableBiMap<ExecutableElement, String> methodToPropertyName =
-          propertyNameToMethodMap(propertyMethods).inverse();
-      builder.get().defineVars(vars, methodToPropertyName);
-    }
+    maybeBuilder.ifPresent(
+        builder -> {
+          ImmutableBiMap<ExecutableElement, String> methodToPropertyName =
+              propertyNameToMethodMap(propertyMethods).inverse();
+          builder.defineVars(vars, methodToPropertyName);
+          vars.builderAnnotations = copiedClassAnnotations(builder.builderType());
+        });
   }
 
   @Override
diff --git a/value/src/main/java/com/google/auto/value/processor/AutoValueTemplateVars.java b/value/src/main/java/com/google/auto/value/processor/AutoValueTemplateVars.java
index 8aec3248..8f855bd0 100644
--- a/value/src/main/java/com/google/auto/value/processor/AutoValueTemplateVars.java
+++ b/value/src/main/java/com/google/auto/value/processor/AutoValueTemplateVars.java
@@ -36,7 +36,7 @@ class AutoValueTemplateVars extends AutoValueOrOneOfTemplateVars {
    * The properties defined by the parent class's abstract methods. The elements of this set are in
    * the same order as the original abstract method declarations in the AutoValue class.
    */
-  ImmutableSet<AutoValueProcessor.Property> props;
+  ImmutableSet<AutoValueOrOneOfProcessor.Property> props;
 
   /**
    * Whether to include identifiers in strings in the generated code. If false, exception messages
@@ -100,6 +100,14 @@ class AutoValueTemplateVars extends AutoValueOrOneOfTemplateVars {
   /** True if the builder being implemented is an interface, false if it is an abstract class. */
   Boolean builderIsInterface = false;
 
+  /**
+   * The full spelling of any annotations to add to the generated builder subclass, or an empty list
+   * if there are none. A non-empty value might look something like {@code
+   * @`java.lang.SuppressWarnings`("Immutable")}. The {@code ``} marks are explained in
+   * {@link TypeEncoder}.
+   */
+  ImmutableList<String> builderAnnotations = ImmutableList.of();
+
   /** The builder's build method, often {@code "build"}. */
   Optional<SimpleMethod> buildMethod = Optional.empty();
 
diff --git a/value/src/main/java/com/google/auto/value/processor/BuilderSpec.java b/value/src/main/java/com/google/auto/value/processor/BuilderSpec.java
index 32e9e6d4..f218891c 100644
--- a/value/src/main/java/com/google/auto/value/processor/BuilderSpec.java
+++ b/value/src/main/java/com/google/auto/value/processor/BuilderSpec.java
@@ -447,11 +447,9 @@ class BuilderSpec {
 
     if (!sameTypeParameters(autoValueClass, builderTypeElement)) {
       errorReporter.reportError(
-          "Type parameters of "
-              + builderTypeElement
-              + " must have same names and bounds as "
-              + "type parameters of "
-              + autoValueClass,
+          String.format(
+              "Type parameters of %s must have same names and bounds as type parameters of %s",
+              builderTypeElement, autoValueClass),
           builderTypeElement);
       return Optional.empty();
     }
diff --git a/value/src/main/java/com/google/auto/value/processor/autovalue.vm b/value/src/main/java/com/google/auto/value/processor/autovalue.vm
index 8fca0e00..80ef79ae 100644
--- a/value/src/main/java/com/google/auto/value/processor/autovalue.vm
+++ b/value/src/main/java/com/google/auto/value/processor/autovalue.vm
@@ -192,6 +192,13 @@ ${modifiers}class $subclass$formalTypes extends $origClass$actualTypes {
 
   #end
 
+  ## BUILDER CLASS
+
+  #foreach ($a in $builderAnnotations)
+
+  $a##
+  #end
+
   static #if ($isFinal) final #end class Builder${builderFormalTypes} ##
   #if ($builderIsInterface) implements #else extends #end
       ${builderTypeName}${builderActualTypes} {
diff --git a/value/userguide/howto.md b/value/userguide/howto.md
index 5f8614c6..6b24a7a1 100644
--- a/value/userguide/howto.md
+++ b/value/userguide/howto.md
@@ -625,6 +625,10 @@ final class AutoValue_Example extends Example {
 }
 ```
 
+Applying `@AutoValue.CopyAnnotations` to an `@AutoValue.Builder` class like
+`Foo.Builder` similarly causes annotations on that class to be copied to the
+generated subclass `AutoValue_Foo.Builder`.
+
 ### Copying to the generated method
 
 For historical reasons, annotations on methods of an `@AutoValue`-annotated