Catch errors when calculating frames in the stack trace (#2408)

Author: elliette

dwds/CHANGELOG.md

@@ -4,6 +4,7 @@
 - Do not persist breakpoints across hot restarts or page reloads. - [#2371](https://github.com/dart-lang/webdev/pull/2371)
 - If `pause_isolates_on_start` is `true`, wait for `resume` to run the app's `main` method. - [#2378](https://github.com/dart-lang/webdev/pull/2378)
 - Fix bug where setting breakpoints in a project using macros would fail. - [#2403](https://github.com/dart-lang/webdev/pull/2403)
+- Make stack trace calculation resilient against one frame throwing an error. - [#2408](https://github.com/dart-lang/webdev/pull/2408)
 
 **Breaking changes**
 

dwds/lib/src/debugging/debugger.dart

@@ -462,7 +462,13 @@ class Debugger extends Domain {
 
     // Don't populate variables for async frames.
     if (populateVariables) {
-      dartFrame.vars = await variablesFor(frame);
+      try {
+        dartFrame.vars = await variablesFor(frame);
+      } catch (e) {
+        logger.warning(
+          'Error calculating Dart variables for frame $frameIndex: $e',
+        );
+      }
     }
 
     return dartFrame;

dwds/lib/src/debugging/frame_computer.dart

@@ -4,10 +4,13 @@
 
 import 'package:dwds/src/debugging/debugger.dart';
 import 'package:dwds/src/utilities/synchronized.dart';
+import 'package:logging/logging.dart';
 import 'package:vm_service/vm_service.dart';
 import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart';
 
 class FrameComputer {
+  static final logger = Logger('FrameComputer');
+
   final Debugger debugger;
 
   // To ensure that the frames are computed only once, we use an atomic queue
@@ -58,12 +61,16 @@ class FrameComputer {
   Future<void> _collectSyncFrames({int? limit}) async {
     while (_frameIndex < _callFrames.length) {
       if (limit != null && _computedFrames.length == limit) return;
-
-      final callFrame = _callFrames[_frameIndex];
-      final dartFrame =
-          await debugger.calculateDartFrameFor(callFrame, _frameIndex++);
-      if (dartFrame != null) {
-        _computedFrames.add(dartFrame);
+      try {
+        final callFrame = _callFrames[_frameIndex];
+        final dartFrame =
+            await debugger.calculateDartFrameFor(callFrame, _frameIndex++);
+        if (dartFrame != null) {
+          _computedFrames.add(dartFrame);
+        }
+      } catch (e) {
+        // If there is an error calculating the frame, then skip it.
+        logger.warning('Error calculating sync frame: $e');
       }
     }
   }
@@ -93,28 +100,33 @@ class FrameComputer {
         final asyncFramesToProcess = _asyncFramesToProcess!;
         // Process a single async frame.
         if (asyncFramesToProcess.isNotEmpty) {
-          final callFrame = asyncFramesToProcess.removeAt(0);
-          final location = WipLocation.fromValues(
-            callFrame.scriptId,
-            callFrame.lineNumber,
-            columnNumber: callFrame.columnNumber,
-          );
-
-          final tempWipFrame = WipCallFrame({
-            'url': callFrame.url,
-            'functionName': callFrame.functionName,
-            'location': location.json,
-            'scopeChain': [],
-          });
-
-          final frame = await debugger.calculateDartFrameFor(
-            tempWipFrame,
-            _frameIndex++,
-            populateVariables: false,
-          );
-          if (frame != null) {
-            frame.kind = FrameKind.kAsyncCausal;
-            _computedFrames.add(frame);
+          try {
+            final callFrame = asyncFramesToProcess.removeAt(0);
+            final location = WipLocation.fromValues(
+              callFrame.scriptId,
+              callFrame.lineNumber,
+              columnNumber: callFrame.columnNumber,
+            );
+
+            final tempWipFrame = WipCallFrame({
+              'url': callFrame.url,
+              'functionName': callFrame.functionName,
+              'location': location.json,
+              'scopeChain': [],
+            });
+
+            final frame = await debugger.calculateDartFrameFor(
+              tempWipFrame,
+              _frameIndex++,
+              populateVariables: false,
+            );
+            if (frame != null) {
+              frame.kind = FrameKind.kAsyncCausal;
+              _computedFrames.add(frame);
+            }
+          } catch (e) {
+            // If there is an error calculating the frame, then skip it.
+            logger.warning('Error calculating async frame: $e');
           }
         }
       }

dwds/test/debugger_test.dart

@@ -204,7 +204,8 @@ void main() async {
         Debugger.logger.onRecord,
         emitsThrough(
           predicate(
-            (LogRecord log) => log.message == 'Error calculating Dart frames',
+            (LogRecord log) =>
+                log.message.contains('Error calculating sync frame'),
           ),
         ),
       );