Use ToStringTransformer from dart frontend_server (#23915)

Author: jensjoha

flutter_frontend_server/lib/server.dart

@@ -16,8 +16,8 @@ import 'package:frontend_server/frontend_server.dart' as frontend
         listenAndCompile,
         argParser,
         usage,
-        ProgramTransformer;
-import 'package:kernel/ast.dart';
+        ProgramTransformer,
+        ToStringTransformer;
 import 'package:path/path.dart' as path;
 import 'package:vm/incremental_compiler.dart';
 
@@ -150,7 +150,7 @@ Future<int> starter(
         ]);
         compiler ??= _FlutterFrontendCompiler(
           output,
-          transformer: ToStringTransformer(null, deleteToStringPackageUris),
+          transformer: frontend.ToStringTransformer(null, deleteToStringPackageUris),
         );
 
         await compiler.compile(input, options);
@@ -170,7 +170,7 @@ Future<int> starter(
   }
 
   compiler ??= _FlutterFrontendCompiler(output,
-      transformer: ToStringTransformer(transformer, deleteToStringPackageUris),
+      transformer: frontend.ToStringTransformer(transformer, deleteToStringPackageUris),
       useDebuggerModuleNames: options['debugger-module-names'] as bool,
       emitDebugMetadata: options['experimental-emit-debug-metadata'] as bool,
       unsafePackageSerialization:
@@ -184,86 +184,3 @@ Future<int> starter(
   frontend.listenAndCompile(compiler, input ?? stdin, options, completer);
   return completer.future;
 }
-
-// Transformer/visitor for toString
-// If we add any more of these, they really should go into a separate library.
-
-/// A [RecursiveVisitor] that replaces [Object.toString] overrides with
-/// `super.toString()`.
-class ToStringVisitor extends RecursiveVisitor<void> {
-  /// The [packageUris] must not be null.
-  ToStringVisitor(this._packageUris) : assert(_packageUris != null);
-
-  /// A set of package URIs to apply this transformer to, e.g. 'dart:ui' and
-  /// 'package:flutter/foundation.dart'.
-  final Set<String> _packageUris;
-
-  /// Turn 'dart:ui' into 'dart:ui', or
-  /// 'package:flutter/src/semantics_event.dart' into 'package:flutter'.
-  String _importUriToPackage(Uri importUri) => '${importUri.scheme}:${importUri.pathSegments.first}';
-
-  bool _isInTargetPackage(Procedure node) {
-    return _packageUris.contains(_importUriToPackage(node.enclosingLibrary.importUri));
-  }
-
-  bool _hasKeepAnnotation(Procedure node) {
-    for (ConstantExpression expression in node.annotations.whereType<ConstantExpression>()) {
-      if (expression.constant is! InstanceConstant) {
-        continue;
-      }
-      final InstanceConstant constant = expression.constant as InstanceConstant;
-      if (constant.classNode.name == '_KeepToString' && constant.classNode.enclosingLibrary.importUri.toString() == 'dart:ui') {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  @override
-  void visitProcedure(Procedure node) {
-    if (
-      node.name.text        == 'toString' &&
-      node.enclosingClass   != null       &&
-      node.enclosingLibrary != null       &&
-      !node.isStatic                      &&
-      !node.isAbstract                    &&
-      !node.enclosingClass.isEnum         &&
-      _isInTargetPackage(node)            &&
-      !_hasKeepAnnotation(node)
-    ) {
-      node.function.body.replaceWith(
-        ReturnStatement(
-          SuperMethodInvocation(
-            node.name,
-            Arguments(<Expression>[]),
-          ),
-        ),
-      );
-    }
-  }
-
-  @override
-  void defaultMember(Member node) {}
-}
-
-/// Replaces [Object.toString] overrides with calls to super for the specified
-/// [packageUris].
-class ToStringTransformer extends frontend.ProgramTransformer {
-  /// The [packageUris] parameter must not be null, but may be empty.
-  ToStringTransformer(this._child, this._packageUris) : assert(_packageUris != null);
-
-  final frontend.ProgramTransformer _child;
-
-  /// A set of package URIs to apply this transformer to, e.g. 'dart:ui' and
-  /// 'package:flutter/foundation.dart'.
-  final Set<String> _packageUris;
-
-  @override
-  void transform(Component component) {
-    assert(_child is! ToStringTransformer);
-    if (_packageUris.isNotEmpty) {
-      component.visitChildren(ToStringVisitor(_packageUris));
-    }
-    _child?.transform(component);
-  }
-}

flutter_frontend_server/test/to_string_test.dart

@@ -4,8 +4,8 @@
 
 import 'dart:io';
 
-import 'package:flutter_frontend_server/server.dart';
-import 'package:frontend_server/frontend_server.dart' as frontend show ProgramTransformer;
+import 'package:frontend_server/frontend_server.dart' as frontend
+    show ProgramTransformer, ToStringTransformer, ToStringVisitor;
 import 'package:kernel/kernel.dart';
 import 'package:mockito/mockito.dart';
 import 'package:path/path.dart' as path;
@@ -25,15 +25,15 @@ void main(List<String> args) async {
   };
 
   test('No packages', () {
-    final ToStringTransformer transformer = ToStringTransformer(null, <String>{});
+    final frontend.ToStringTransformer transformer = frontend.ToStringTransformer(null, <String>{});
 
     final MockComponent component = MockComponent();
     transformer.transform(component);
     verifyNever(component.visitChildren(any));
   });
 
   test('dart:ui package', () {
-    final ToStringTransformer transformer = ToStringTransformer(null, uiAndFlutter);
+    final frontend.ToStringTransformer transformer = frontend.ToStringTransformer(null, uiAndFlutter);
 
     final MockComponent component = MockComponent();
     transformer.transform(component);
@@ -42,7 +42,7 @@ void main(List<String> args) async {
 
   test('Child transformer', () {
     final MockTransformer childTransformer = MockTransformer();
-    final ToStringTransformer transformer = ToStringTransformer(childTransformer, <String>{});
+    final frontend.ToStringTransformer transformer = frontend.ToStringTransformer(childTransformer, <String>{});
 
     final MockComponent component = MockComponent();
     transformer.transform(component);
@@ -51,7 +51,7 @@ void main(List<String> args) async {
   });
 
   test('ToStringVisitor ignores non-toString procedures', () {
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     when(procedure.name).thenReturn(Name('main'));
     when(procedure.annotations).thenReturn(const <Expression>[]);
@@ -65,7 +65,7 @@ void main(List<String> args) async {
     //
     // void main() {}
     // String toString() => 'why?';
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     final MockFunctionNode function = MockFunctionNode();
     final MockStatement statement = MockStatement();
@@ -84,7 +84,7 @@ void main(List<String> args) async {
   });
 
   test('ToStringVisitor ignores abstract toString', () {
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     final MockFunctionNode function = MockFunctionNode();
     final MockStatement statement = MockStatement();
@@ -103,7 +103,7 @@ void main(List<String> args) async {
   });
 
   test('ToStringVisitor ignores static toString', () {
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     final MockFunctionNode function = MockFunctionNode();
     final MockStatement statement = MockStatement();
@@ -122,7 +122,7 @@ void main(List<String> args) async {
   });
 
   test('ToStringVisitor ignores enum toString', () {
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     final MockFunctionNode function = MockFunctionNode();
     final MockStatement statement = MockStatement();
@@ -141,7 +141,7 @@ void main(List<String> args) async {
   });
 
   test('ToStringVisitor ignores non-specified libraries', () {
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     final MockFunctionNode function = MockFunctionNode();
     final MockStatement statement = MockStatement();
@@ -160,7 +160,7 @@ void main(List<String> args) async {
   });
 
   test('ToStringVisitor ignores @keepToString', () {
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     final MockFunctionNode function = MockFunctionNode();
     final MockStatement statement = MockStatement();
@@ -198,7 +198,7 @@ void main(List<String> args) async {
   }
 
   test('ToStringVisitor replaces toString in specified libraries (dart:ui)', () {
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     final MockFunctionNode function = MockFunctionNode();
     final MockStatement statement = MockStatement();
@@ -219,7 +219,7 @@ void main(List<String> args) async {
   });
 
   test('ToStringVisitor replaces toString in specified libraries (package:flutter)', () {
-    final ToStringVisitor visitor = ToStringVisitor(uiAndFlutter);
+    final frontend.ToStringVisitor visitor = frontend.ToStringVisitor(uiAndFlutter);
     final MockProcedure procedure = MockProcedure();
     final MockFunctionNode function = MockFunctionNode();
     final MockStatement statement = MockStatement();