[pigeon] Adds @CanIgnoreReturnValue annotation

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 15.0.1
+
+* [java] Adds @CanIgnoreReturnValue annotation to class builder.
+
 ## 15.0.0
 
 * **Breaking Change** [kotlin] Updates Flutter API to use new errorClassName.

packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java

@@ -4,6 +4,9 @@
 // Autogenerated from Pigeon, do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.CLASS;
+
 import android.util.Log;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -12,6 +15,8 @@
 import io.flutter.plugin.common.MessageCodec;
 import io.flutter.plugin.common.StandardMessageCodec;
 import java.io.ByteArrayOutputStream;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -61,6 +66,10 @@ protected static FlutterError createConnectionError(@NonNull String channelName)
         "channel-error", "Unable to establish connection on channel: " + channelName + ".", "");
   }
 
+  @Target(METHOD)
+  @Retention(CLASS)
+  @interface CanIgnoreReturnValue {}
+
   public enum Code {
     ONE(0),
     TWO(1);
@@ -127,27 +136,31 @@ public static final class Builder {
 
       private @Nullable String name;
 
+      @CanIgnoreReturnValue
       public @NonNull Builder setName(@Nullable String setterArg) {
         this.name = setterArg;
         return this;
       }
 
       private @Nullable String description;
 
+      @CanIgnoreReturnValue
       public @NonNull Builder setDescription(@Nullable String setterArg) {
         this.description = setterArg;
         return this;
       }
 
       private @Nullable Code code;
 
+      @CanIgnoreReturnValue
       public @NonNull Builder setCode(@NonNull Code setterArg) {
         this.code = setterArg;
         return this;
       }
 
       private @Nullable Map<String, String> data;
 
+      @CanIgnoreReturnValue
       public @NonNull Builder setData(@NonNull Map<String, String> setterArg) {
         this.data = setterArg;
         return this;

packages/pigeon/lib/generator_tools.dart

@@ -13,7 +13,7 @@ import 'ast.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '15.0.0';
+const String pigeonVersion = '15.0.1';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/java_generator.dart

@@ -116,6 +116,12 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
       indent.writeln('package ${generatorOptions.package};');
       indent.newln();
     }
+    if (root.classes.isNotEmpty) {
+      indent.writeln('import static java.lang.annotation.ElementType.METHOD;');
+      indent
+          .writeln('import static java.lang.annotation.RetentionPolicy.CLASS;');
+      indent.newln();
+    }
     indent.writeln('import android.util.Log;');
     indent.writeln('import androidx.annotation.NonNull;');
     indent.writeln('import androidx.annotation.Nullable;');
@@ -124,6 +130,10 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
     indent.writeln('import io.flutter.plugin.common.MessageCodec;');
     indent.writeln('import io.flutter.plugin.common.StandardMessageCodec;');
     indent.writeln('import java.io.ByteArrayOutputStream;');
+    if (root.classes.isNotEmpty) {
+      indent.writeln('import java.lang.annotation.Retention;');
+      indent.writeln('import java.lang.annotation.Target;');
+    }
     indent.writeln('import java.nio.ByteBuffer;');
     indent.writeln('import java.util.ArrayList;');
     indent.writeln('import java.util.Arrays;');
@@ -290,6 +300,7 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
         indent.writeln(
             'private @Nullable ${hostDatatype.datatype} ${field.name};');
         indent.newln();
+        indent.writeln('@CanIgnoreReturnValue');
         indent.writeScoped(
             'public @NonNull Builder ${_makeSetter(field)}($nullability ${hostDatatype.datatype} setterArg) {',
             '}', () {
@@ -939,6 +950,17 @@ protected static ArrayList<Object> wrapError(@NonNull Throwable exception) {
     });
   }
 
+  // We are emitting our own definition of [@CanIgnoreReturnValue] to support
+  // clients who use CheckReturnValue, without having to force Pigeon clients
+  // to take a new dependency on error_prone_annotations.
+  void _writeCanIgnoreReturnValueAnnotation(
+      JavaOptions opt, Root root, Indent indent) {
+    indent.newln();
+    indent.writeln('@Target(METHOD)');
+    indent.writeln('@Retention(CLASS)');
+    indent.writeln('@interface CanIgnoreReturnValue {}');
+  }
+
   @override
   void writeGeneralUtilities(
     JavaOptions generatorOptions,
@@ -961,6 +983,9 @@ protected static ArrayList<Object> wrapError(@NonNull Throwable exception) {
       indent.newln();
       _writeCreateConnectionError(indent);
     }
+    if (root.classes.isNotEmpty) {
+      _writeCanIgnoreReturnValueAnnotation(generatorOptions, root, indent);
+    }
   }
 
   @override