Dart Debug Extension gracefully handles disconnection (#1582)

Author: elliette

dwds/debug_extension/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.29
+
+- Notify the debugger and inspector panels when the debug session is disconnected.
+
 ## 1.28
 
 - Support Chrome 100 updates to the remote debugging protocol.

dwds/debug_extension/pubspec.yaml

@@ -1,6 +1,6 @@
 name: extension
 publish_to: none
-version: 1.28.0
+version: 1.29.0
 homepage: https://github.com/dart-lang/webdev
 description: >-
   A chrome extension for Dart debugging.

dwds/debug_extension/web/background.dart

@@ -104,11 +104,11 @@ void main() {
 
   // When a Dart application tab is closed, detach the corresponding debug
   // session:
-  tabsOnRemovedAddListener(allowInterop(_maybeDetachDebugSessionForTab));
+  tabsOnRemovedAddListener(allowInterop(_removeAndDetachDebugSessionForTab));
 
   // When a debug session is detached, remove the reference to it:
   onDetachAddListener(allowInterop((Debuggee source, DetachReason reason) {
-    _maybeRemoveDebugSessionForTab(source.tabId);
+    _removeDebugSessionForTab(source.tabId);
   }));
 
   // Save the tab ID for the opened DevTools.
@@ -277,14 +277,38 @@ void _maybeAttachDebugSession(
   }
 }
 
-void _maybeDetachDebugSessionForTab(int tabId, _) {
-  final removedTabId = _maybeRemoveDebugSessionForTab(tabId);
+// Tries to remove the debug session for the specified tab, and detach the
+// debugger associated with that debug session.
+void _removeAndDetachDebugSessionForTab(int tabId, _) {
+  final removedTabId = _removeDebugSessionForTab(tabId);
 
   if (removedTabId != -1) {
     detach(Debuggee(tabId: removedTabId), allowInterop(() {}));
   }
 }
 
+// Tries to remove the debug session for the specified tab. If no session is
+// found, returns -1. Otherwise returns the tab ID.
+int _removeDebugSessionForTab(int tabId) {
+  var session = _debugSessions.firstWhere(
+      (session) => session.appTabId == tabId || session.devtoolsTabId == tabId,
+      orElse: () => null);
+  if (session != null) {
+    session.socketClient.close();
+    _debugSessions.remove(session);
+
+    // Notify the Dart DevTools panel that the session has been detached by
+    // setting the URI to an empty string:
+    _updateOrCreateDevToolsPanel(session.appId, (panel) {
+      panel.devToolsUri = '';
+    });
+
+    return session.appTabId;
+  } else {
+    return -1;
+  }
+}
+
 void _maybeSaveDevToolsTabId(Tab tab) async {
   // Remembers the ID of the DevTools tab.
   //
@@ -338,28 +362,6 @@ void _forwardMessageToExternalExtensions(
   }
 }
 
-// Tries to remove the debug session for the specified tab. If no session is
-// found, returns -1. Otherwise returns the tab ID.
-int _maybeRemoveDebugSessionForTab(int tabId) {
-  var session = _debugSessions.firstWhere(
-      (session) => session.appTabId == tabId || session.devtoolsTabId == tabId,
-      orElse: () => null);
-  if (session != null) {
-    session.socketClient.close();
-    _debugSessions.remove(session);
-
-    // Notify the Dart DevTools panel that the session has been detached by
-    // setting the URI to an empty string:
-    _updateOrCreateDevToolsPanel(session.appId, (panel) {
-      panel.devToolsUri = '';
-    });
-
-    return session.appTabId;
-  } else {
-    return -1;
-  }
-}
-
 void _notifyPanelScriptOfChanges(List<DevToolsPanel> panels) {
   for (final panel in panels) {
     sendSimpleMessage(panel.panelId,
@@ -500,12 +502,12 @@ Future<void> _startSseClient(
     }
   }, onDone: () {
     _tabIdToEncodedUri.remove(currentTab.id);
-    client.close();
+    _removeAndDetachDebugSessionForTab(currentTab.id, null);
     return;
   }, onError: (_) {
     _tabIdToEncodedUri.remove(currentTab.id);
     alert('Lost app connection.');
-    client.close();
+    _removeAndDetachDebugSessionForTab(currentTab.id, null);
   }, cancelOnError: true);
 
   client.sink.add(jsonEncode(serializers.serialize(DevToolsRequest((b) => b