In AutoValue builders, support setting a property of type Optional<T> via a setter with an argument of type T.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=120943277

5 files changed, 70 insertions, 12 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 c17eb94c..4c5d4b43 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
@@ -1290,6 +1290,7 @@ public class AutoValueTest extends TestCase {
     @AutoValue.Builder
     public interface Builder {
       Builder setOptionalString(com.google.common.base.Optional<String> s);
+      Builder setOptionalString(String s);
       OptionalPropertyWithBuilder build();
     }
   }
@@ -1302,6 +1303,11 @@ public class AutoValueTest extends TestCase {
         .setOptionalString(com.google.common.base.Optional.of("foo"))
         .build();
     assertThat(supplied.optionalString()).hasValue("foo");
+
+    OptionalPropertyWithBuilder suppliedDirectly = OptionalPropertyWithBuilder.builder()
+        .setOptionalString("foo")
+        .build();
+    assertThat(suppliedDirectly.optionalString()).hasValue("foo");
   }
 
   @AutoValue
@@ -1332,6 +1338,33 @@ public class AutoValueTest extends TestCase {
   }
 
   @AutoValue
+  public abstract static class OptionalPropertyWithBuilderSimpleSetter {
+    public abstract com.google.common.base.Optional<String> optionalString();
+
+    public static Builder builder() {
+      return new AutoValue_AutoValueTest_OptionalPropertyWithBuilderSimpleSetter.Builder();
+    }
+
+    @AutoValue.Builder
+    public interface Builder {
+      Builder setOptionalString(String s);
+      OptionalPropertyWithBuilderSimpleSetter build();
+    }
+  }
+
+  public void testOptionalPropertySimpleSetter() {
+    OptionalPropertyWithBuilderSimpleSetter omitted =
+        OptionalPropertyWithBuilderSimpleSetter.builder().build();
+    assertThat(omitted.optionalString()).isAbsent();
+
+    OptionalPropertyWithBuilderSimpleSetter supplied =
+        OptionalPropertyWithBuilderSimpleSetter.builder()
+            .setOptionalString("foo")
+            .build();
+    assertThat(supplied.optionalString()).hasValue("foo");
+  }
+
+  @AutoValue
   public abstract static class GenericsWithBuilder<T extends Number & Comparable<T>, U extends T> {
     public abstract List<T> list();
     public abstract U u();
diff --git a/value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifier.java b/value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifier.java
index 56148565..10afdee7 100644
--- a/value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifier.java
+++ b/value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifier.java
@@ -368,7 +368,7 @@ class BuilderMethodClassifier {
   /**
    * Checks that the given setter method has a parameter type that is compatible with the return
    * type of the given getter. Compatible means either that it is the same, or that it is a type
-   * that can be copied using a method like {@code ImmutableList.copyOf}.
+   * that can be copied using a method like {@code ImmutableList.copyOf} or {@code Optional.of}.
    *
    * @return true if the types correspond, false if an error has been reported.
    */
@@ -459,11 +459,12 @@ class BuilderMethodClassifier {
     if (!targetType.getKind().equals(TypeKind.DECLARED)) {
       return ImmutableList.of();
     }
+    String copyOf = Optionalish.isOptional(targetType) ? "of" : "copyOf";
     TypeElement immutableTargetType = MoreElements.asType(typeUtils.asElement(targetType));
     ImmutableList.Builder<ExecutableElement> copyOfMethods = ImmutableList.builder();
     for (ExecutableElement method :
         ElementFilter.methodsIn(immutableTargetType.getEnclosedElements())) {
-      if (method.getSimpleName().contentEquals("copyOf")
+      if (method.getSimpleName().contentEquals(copyOf)
           && method.getParameters().size() == 1
           && method.getModifiers().contains(Modifier.STATIC)) {
         copyOfMethods.add(method);
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 9c5aec99..4db8552d 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
@@ -260,7 +260,8 @@ class BuilderSpec {
    * method {@code foo(T)} or {@code setFoo(T)} that returns the builder type. Additionally, it
    * can have a setter with a type that can be copied to {@code T} through a {@code copyOf} method;
    * for example a property {@code foo} of type {@code ImmutableSet<String>} can be set with a
-   * method {@code setFoo(Collection<String> foos)}.
+   * method {@code setFoo(Collection<String> foos)}. And, if {@code T} is {@code Optional},
+   * it can have a setter with a type that can be copied to {@code T} through {@code Optional.of}.
    */
   public class PropertySetter {
     private final String name;
@@ -279,9 +280,13 @@ class BuilderSpec {
       Types typeUtils = processingEnv.getTypeUtils();
       TypeMirror erasedPropertyType = typeUtils.erasure(propertyType);
       boolean sameType = typeUtils.isSameType(typeUtils.erasure(parameterType), erasedPropertyType);
-      this.copyOf = sameType
-          ? null
-          : typeSimplifier.simplifyRaw(erasedPropertyType) + ".copyOf(%s)";
+      if (sameType) {
+        this.copyOf = null;
+      } else {
+        String rawTarget = typeSimplifier.simplifyRaw(erasedPropertyType);
+        String of = Optionalish.isOptional(propertyType) ? "of" : "copyOf";
+        this.copyOf = rawTarget + "." + of + "(%s)";
+      }
     }
 
     public String getName() {
diff --git a/value/src/main/java/com/google/auto/value/processor/Optionalish.java b/value/src/main/java/com/google/auto/value/processor/Optionalish.java
index b19f72d5..e4fbd283 100644
--- a/value/src/main/java/com/google/auto/value/processor/Optionalish.java
+++ b/value/src/main/java/com/google/auto/value/processor/Optionalish.java
@@ -2,6 +2,7 @@ package com.google.auto.value.processor;
 
 import com.google.auto.common.MoreElements;
 import com.google.auto.common.MoreTypes;
+import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableSet;
 
 import javax.lang.model.element.TypeElement;
@@ -41,22 +42,33 @@ public class Optionalish {
    *     {@code OptionalInt}, etc. In cases of ambiguity it might be {@code java.util.Optional} etc.
    */
   static Optionalish createIfOptional(TypeMirror type, String rawTypeSpelling) {
+    TypeElement optionalType = asOptionalTypeElement(type);
+    if (optionalType == null) {
+      return null;
+    } else {
+      return new Optionalish(optionalType, Preconditions.checkNotNull(rawTypeSpelling));
+    }
+  }
+
+  static boolean isOptional(TypeMirror type) {
+    return asOptionalTypeElement(type) != null;
+  }
+
+  private static TypeElement asOptionalTypeElement(TypeMirror type) {
     if (type.getKind() != TypeKind.DECLARED) {
       return null;
     }
     DeclaredType declaredType = MoreTypes.asDeclared(type);
     TypeElement typeElement = MoreElements.asType(declaredType.asElement());
-    if (OPTIONAL_CLASS_NAMES.contains(typeElement.getQualifiedName().toString())) {
-      return new Optionalish(typeElement, rawTypeSpelling);
-    } else {
-      return null;
-    }
+    return OPTIONAL_CLASS_NAMES.contains(typeElement.getQualifiedName().toString())
+        ? typeElement
+        : null;
   }
 
   /**
    * Returns a string representing the method call to obtain the empty version of this Optional.
    * This will be something like {@code "Optional.empty()"} or possibly
-   * {@code java.util.Optional.empty()}. It does not have a final semicolon.
+   * {@code "java.util.Optional.empty()"}. It does not have a final semicolon.
    *
    * <p>This method is public so that it can be referenced as {@code p.optional.empty} from
    * templates.
diff --git a/value/src/test/java/com/google/auto/value/processor/CompilationTest.java b/value/src/test/java/com/google/auto/value/processor/CompilationTest.java
index 34947567..dc5323a8 100644
--- a/value/src/test/java/com/google/auto/value/processor/CompilationTest.java
+++ b/value/src/test/java/com/google/auto/value/processor/CompilationTest.java
@@ -615,6 +615,7 @@ public class CompilationTest {
         "    Builder<T> anImmutableList(List<T> x);",
         "    ImmutableList.Builder<T> anImmutableListBuilder();",
         "    Builder<T> anOptionalString(Optional<String> s);",
+        "    Builder<T> anOptionalString(String s);",
         "",
         "    List<T> aList();",
         "    ImmutableList<T> anImmutableList();",
@@ -829,6 +830,12 @@ public class CompilationTest {
         "    }",
         "",
         "    @Override",
+        "    public Baz.Builder<T> anOptionalString(String anOptionalString) {",
+        "      this.anOptionalString = Optional.of(anOptionalString);",
+        "      return this;",
+        "    }",
+        "",
+        "    @Override",
         "    public Baz<T> build() {",
         "      if (anImmutableListBuilder$ != null) {",
         "        anImmutableList = anImmutableListBuilder$.build();",