Convert expression evaluation exceptions to errors (#54916)

packages/flutter_tools/lib/src/build_runner/devfs_web.dart

@@ -77,7 +77,8 @@ class WebExpressionCompiler implements ExpressionCompiler {
           content, compilerOutput.errorCount > 0);
     }
 
-    throw Exception('Failed to compile $expression');
+    return ExpressionCompilationResult(
+      'InternalError: frontend server failed to compile \'$expression\'', true);
   }
 }
 

packages/flutter_tools/lib/src/compile.dart

@@ -856,7 +856,7 @@ class DefaultResidentCompiler implements ResidentCompiler {
   }
 
   Future<CompilerOutput> _compileExpressionToJs(_CompileExpressionToJsRequest request) async {
-    _stdoutHandler.reset(suppressCompilerMessages: true, expectSources: false);
+    _stdoutHandler.reset(suppressCompilerMessages: false, expectSources: false);
 
     // 'compile-expression-to-js' should be invoked after compiler has been started,
     // program was compiled.

packages/flutter_tools/lib/src/resident_runner.dart

@@ -17,6 +17,7 @@ import 'base/file_system.dart';
 import 'base/io.dart' as io;
 import 'base/logger.dart';
 import 'base/signals.dart';
+import 'base/terminal.dart';
 import 'base/utils.dart';
 import 'build_info.dart';
 import 'codegen.dart';
@@ -92,6 +93,9 @@ class FlutterDevice {
         // Override the filesystem scheme so that the frontend_server can find
         // the generated entrypoint code.
         fileSystemScheme: 'org-dartlang-app',
+        compilerMessageConsumer:
+          (String message, {bool emphasis, TerminalColor color, }) =>
+            globals.printTrace(message),
         initializeFromDill: globals.fs.path.join(getBuildDirectory(), 'cache.dill'),
         targetModel: TargetModel.dartdevc,
         experimentalFlags: experimentalFlags,

packages/flutter_tools/test/general.shard/web/web_expression_compiler_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:dwds/dwds.dart';
+import 'package:flutter_tools/src/compile.dart';
+import 'package:flutter_tools/src/build_runner/devfs_web.dart';
+import 'package:matcher/matcher.dart';
+import 'package:mockito/mockito.dart';
+import 'package:flutter_tools/src/globals.dart' as globals;
+
+import '../../src/common.dart';
+import '../../src/testbed.dart';
+
+void main() {
+  Testbed testbed;
+
+  setUp(() {
+    testbed = Testbed();
+  });
+
+  test('WebExpressionCompiler handles successful expression compilation', () => testbed.run(() async {
+    globals.fs.file('compilerOutput').writeAsStringSync('a');
+
+    final ResidentCompiler residentCompiler = MockResidentCompiler();
+    when(residentCompiler.compileExpressionToJs(
+      any, any, any, any, any, any, any
+    )).thenAnswer((Invocation invocation) async {
+      return const CompilerOutput('compilerOutput', 0, <Uri>[]);
+    });
+
+    final ExpressionCompiler expressionCompiler =
+      WebExpressionCompiler(residentCompiler);
+
+    final ExpressionCompilationResult result =
+      await expressionCompiler.compileExpressionToJs(
+        null, null, 1, 1, null, null, null, null);
+
+    expectResult(result, false, 'a');
+  }));
+
+  test('WebExpressionCompiler handles compilation error', () => testbed.run(() async {
+    globals.fs.file('compilerOutput').writeAsStringSync('Error: a');
+
+    final ResidentCompiler residentCompiler = MockResidentCompiler();
+    when(residentCompiler.compileExpressionToJs(
+      any, any, any, any, any, any, any
+    )).thenAnswer((Invocation invocation) async {
+      return const CompilerOutput('compilerOutput', 1, <Uri>[]);
+    });
+
+    final ExpressionCompiler expressionCompiler =
+      WebExpressionCompiler(residentCompiler);
+
+    final ExpressionCompilationResult result =
+      await expressionCompiler.compileExpressionToJs(
+        null, null, 1, 1, null, null, null, null);
+
+    expectResult(result, true, 'Error: a');
+  }));
+
+  test('WebExpressionCompiler handles internal error', () => testbed.run(() async {
+    final ResidentCompiler residentCompiler = MockResidentCompiler();
+    when(residentCompiler.compileExpressionToJs(
+      any, any, any, any, any, any, any
+    )).thenAnswer((Invocation invocation) async {
+      return null;
+    });
+
+    final ExpressionCompiler expressionCompiler =
+      WebExpressionCompiler(residentCompiler);
+
+    final ExpressionCompilationResult result =
+      await expressionCompiler.compileExpressionToJs(
+        null, null, 1, 1, null, null, null, 'a');
+
+    expectResult(result, true, 'InternalError: frontend server failed to compile \'a\'');
+  }));
+}
+
+void expectResult(ExpressionCompilationResult result, bool isError, String value) {
+  expect(result,
+    const TypeMatcher<ExpressionCompilationResult>()
+      .having((ExpressionCompilationResult instance) => instance.isError, 'isError', isError)
+      .having((ExpressionCompilationResult instance) =>instance.result, 'result', value));
+}
+
+class MockResidentCompiler extends Mock implements ResidentCompiler {}

packages/flutter_tools/test/integration.shard/expression_evaluation_test.dart

@@ -7,6 +7,7 @@ import 'dart:io';
 
 import 'package:file/file.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:matcher/matcher.dart';
 
 import 'package:vm_service/vm_service.dart';
 
@@ -146,32 +147,51 @@ void batch2() {
 }
 
 Future<void> evaluateTrivialExpressions(FlutterTestDriver flutter) async {
-  InstanceRef res;
+  ObjRef res;
 
   res = await flutter.evaluateInFrame('"test"');
-  expect(res.kind == InstanceKind.kString && res.valueAsString == 'test', isTrue);
+  expectValueOfType(res, InstanceKind.kString, 'test');
 
   res = await flutter.evaluateInFrame('1');
-  expect(res.kind == InstanceKind.kInt && res.valueAsString == 1.toString(), isTrue);
+  expectValueOfType(res, InstanceKind.kInt, 1.toString());
 
   res = await flutter.evaluateInFrame('true');
-  expect(res.kind == InstanceKind.kBool && res.valueAsString == true.toString(), isTrue);
+  expectValueOfType(res, InstanceKind.kBool, true.toString());
 }
 
 Future<void> evaluateComplexExpressions(FlutterTestDriver flutter) async {
-  final InstanceRef res = await flutter.evaluateInFrame('new DateTime.now().year');
-  expect(res.kind == InstanceKind.kInt && res.valueAsString == DateTime.now().year.toString(), isTrue);
+  final ObjRef res = await flutter.evaluateInFrame('new DateTime.now().year');
+  expectValueOfType(res, InstanceKind.kInt, DateTime.now().year.toString());
 }
 
 Future<void> evaluateComplexReturningExpressions(FlutterTestDriver flutter) async {
   final DateTime now = DateTime.now();
-  final InstanceRef resp = await flutter.evaluateInFrame('new DateTime.now()');
-  expect(resp.classRef.name, equals('DateTime'));
+  final ObjRef resp = await flutter.evaluateInFrame('new DateTime.now()');
+  expectInstanceOfClass(resp, 'DateTime');
   // Ensure we got a reasonable approximation. The more accurate we try to
   // make this, the more likely it'll fail due to differences in the time
   // in the remote VM and the local VM at the time the code runs.
   final InstanceRef res = await flutter.evaluate(resp.id, r'"$year-$month-$day"');
-  expect(res.valueAsString, equals('${now.year}-${now.month}-${now.day}'));
+  expectValue(res, '${now.year}-${now.month}-${now.day}');
+}
+
+void expectInstanceOfClass(ObjRef result, String name) {
+  expect(result,
+    const TypeMatcher<InstanceRef>()
+      .having((InstanceRef instance) => instance.classRef.name, 'resp.classRef.name', name));
+}
+
+void expectValueOfType(ObjRef result, String kind, String message) {
+  expect(result,
+    const TypeMatcher<InstanceRef>()
+      .having((InstanceRef instance) => instance.kind, 'kind', kind)
+      .having((InstanceRef instance) => instance.valueAsString, 'valueAsString', message));
+}
+
+void expectValue(ObjRef result, String message) {
+  expect(result,
+    const TypeMatcher<InstanceRef>()
+      .having((InstanceRef instance) => instance.valueAsString, 'valueAsString', message));
 }
 
 void main() {

packages/flutter_tools/test/integration.shard/expression_evaluation_web_test.dart

@@ -7,6 +7,7 @@ import 'dart:io';
 
 import 'package:file/file.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:matcher/matcher.dart';
 
 import 'package:vm_service/vm_service.dart';
 
@@ -46,6 +47,14 @@ void batch1() {
     );
   }
 
+  test('flutter run expression evaluation - can handle compilation errors', () async {
+    await initProject();
+    await _flutter.run(withDebugger: true, chrome: true);
+    await breakInTopLevelFunction(_flutter);
+    await evaluateErrorExpressions(_flutter);
+    await cleanProject();
+  }, skip: 'CI not setup for web tests'); // https://github.com/flutter/flutter/issues/53779
+
   test('flutter run expression evaluation - can evaluate trivial expressions in top level function', () async {
     await initProject();
     await _flutter.run(withDebugger: true, chrome: true);
@@ -77,22 +86,6 @@ void batch1() {
     await evaluateComplexExpressions(_flutter);
     await cleanProject();
   }, skip: 'CI not setup for web tests'); // https://github.com/flutter/flutter/issues/53779
-
-  test('flutter run expression evaluation - can evaluate expressions returning complex objects in top level function', () async {
-    await initProject();
-    await _flutter.run(withDebugger: true, chrome: true);
-    await breakInTopLevelFunction(_flutter);
-    await evaluateComplexReturningExpressions(_flutter);
-    await cleanProject();
-  }, skip: 'Evaluate on objects is not supported for web yet');
-
-  test('flutter run expression evaluation - can evaluate expressions returning complex objects in build method', () async {
-    await initProject();
-    await _flutter.run(withDebugger: true, chrome: true);
-    await breakInBuildMethod(_flutter);
-    await evaluateComplexReturningExpressions(_flutter);
-    await cleanProject();
-  }, skip: 'Evaluate on objects is not supported for web yet');
 }
 
 void batch2() {
@@ -133,43 +126,43 @@ void batch2() {
     await evaluateComplexExpressions(_flutter);
     await cleanProject();
   }, skip: 'CI not setup for web tests'); // https://github.com/flutter/flutter/issues/53779
+}
 
-  test('flutter test expression evaluation - can evaluate expressions returning complex objects in a test', () async {
-    await initProject();
-    await _flutter.run(withDebugger: true, chrome: true, script: _project.testFilePath);
-    await breakInMethod(_flutter);
-    await evaluateComplexReturningExpressions(_flutter);
-    await cleanProject();
-  }, skip: 'Evaluate on objects is not supported for web yet');
+
+Future<void> evaluateErrorExpressions(FlutterTestDriver flutter) async {
+  final ObjRef res = await flutter.evaluateInFrame('typo');
+  expectError(res, 'CompilationError: Getter not found: \'typo\'.\ntypo\n^^^^');
 }
 
 Future<void> evaluateTrivialExpressions(FlutterTestDriver flutter) async {
-  InstanceRef res;
+  ObjRef res;
 
   res = await flutter.evaluateInFrame('"test"');
-  expect(res.kind == InstanceKind.kString && res.valueAsString == 'test', isTrue);
+  expectInstance(res, InstanceKind.kString, 'test');
 
   res = await flutter.evaluateInFrame('1');
-  expect(res.kind == InstanceKind.kDouble && res.valueAsString == 1.toString(), isTrue);
+  expectInstance(res, InstanceKind.kDouble, 1.toString());
 
   res = await flutter.evaluateInFrame('true');
-  expect(res.kind == InstanceKind.kBool && res.valueAsString == true.toString(), isTrue);
+  expectInstance(res, InstanceKind.kBool, true.toString());
 }
 
 Future<void> evaluateComplexExpressions(FlutterTestDriver flutter) async {
-  final InstanceRef res = await flutter.evaluateInFrame('new DateTime.now().year');
-  expect(res.kind == InstanceKind.kDouble && res.valueAsString == DateTime.now().year.toString(), isTrue);
+  final ObjRef res = await flutter.evaluateInFrame('new DateTime.now().year');
+  expectInstance(res, InstanceKind.kDouble, DateTime.now().year.toString());
+}
+
+void expectInstance(ObjRef result, String kind, String message) {
+  expect(result,
+    const TypeMatcher<InstanceRef>()
+      .having((InstanceRef instance) => instance.kind, 'kind', kind)
+      .having((InstanceRef instance) => instance.valueAsString, 'valueAsString', message));
 }
 
-Future<void> evaluateComplexReturningExpressions(FlutterTestDriver flutter) async {
-  final DateTime now = DateTime.now();
-  final InstanceRef resp = await flutter.evaluateInFrame('new DateTime.now()');
-  expect(resp.classRef.name, equals('DateTime'));
-  // Ensure we got a reasonable approximation. The more accurate we try to
-  // make this, the more likely it'll fail due to differences in the time
-  // in the remote VM and the local VM at the time the code runs.
-  final InstanceRef res = await flutter.evaluate(resp.id, r'"$year-$month-$day"');
-  expect(res.valueAsString, equals('${now.year}-${now.month}-${now.day}'));
+void expectError(ObjRef result, String message) {
+  expect(result,
+    const TypeMatcher<ErrorRef>()
+      .having((ErrorRef instance) => instance.message, 'message', message));
 }
 
 void main() {

packages/flutter_tools/test/integration.shard/test_driver.dart

@@ -291,9 +291,9 @@ abstract class FlutterTestDriver {
     return waitForNextPause ? waitForPause() : null;
   }
 
-  Future<InstanceRef> evaluateInFrame(String expression) async {
-    return _timeoutWithMessages<InstanceRef>(
-      () async => await _vmService.evaluateInFrame(await _getFlutterIsolateId(), 0, expression) as InstanceRef,
+  Future<ObjRef> evaluateInFrame(String expression) async {
+    return _timeoutWithMessages<ObjRef>(
+      () async => await _vmService.evaluateInFrame(await _getFlutterIsolateId(), 0, expression) as ObjRef,
       task: 'Evaluating expression ($expression)',
     );
   }