DAS plugins: Log an isolate-spawning exception to terminal

Change-Id: Iafe061914a34d883b2683b5edae0ee73f75325c0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/413320
Commit-Queue: Samuel Rawlins <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: srawlins

pkg/analysis_server/lib/src/plugin/plugin_manager.dart

@@ -207,13 +207,20 @@ abstract class PluginInfo {
 
   void reportException(CaughtException exception) {
     // If a previous exception has been reported, do not replace it here; the
-    //first should have more "root cause" information.
+    // first should have more "root cause" information.
     _exception ??= exception;
     instrumentationService.logPluginException(
       data,
       exception.exception,
       exception.stackTrace,
     );
+    var message =
+        'An error occurred while executing an analyzer plugin: '
+        // Sometimes the message is the primary information; sometimes the
+        // exception is.
+        '${exception.message ?? exception.exception}\n'
+        '${exception.stackTrace}';
+    notificationManager.handlePluginError(message);
   }
 
   /// If the plugin is currently running, send a request based on the given
@@ -989,11 +996,19 @@ class PluginSession {
 
   /// Handle the fact that an unhandled error has occurred in the plugin.
   void handleOnError(dynamic error) {
-    var errorPair = (error as List).cast<String>();
-    var stackTrace = StackTrace.fromString(errorPair[1]);
-    info.reportException(
-      CaughtException(PluginException(errorPair[0]), stackTrace),
-    );
+    if (error case [String message, String stackTraceString]) {
+      var stackTrace = StackTrace.fromString(stackTraceString);
+      var exception = PluginException(message);
+      info.reportException(
+        CaughtException.withMessage(message, exception, stackTrace),
+      );
+    } else {
+      throw ArgumentError.value(
+        error,
+        'error',
+        'expected to be a two-element List of Strings.',
+      );
+    }
   }
 
   /// Handle a [response] from the plugin by completing the future that was

pkg/analysis_server/test/src/plugin/plugin_manager_test.dart

@@ -739,10 +739,12 @@ class PluginSessionTest with ResourceProviderMixin {
     expect(session.pluginStoppedCompleter.isCompleted, isTrue);
   }
 
-  @failingTest
   void test_handleOnError() {
     session.handleOnError(<String>['message', 'trace']);
-    fail('The method handleOnError is not implemented');
+    expect(
+      notificationManager.pluginErrors.first,
+      'An error occurred while executing an analyzer plugin: message\ntrace',
+    );
   }
 
   Future<void> test_handleResponse() async {
@@ -781,6 +783,13 @@ class PluginSessionTest with ResourceProviderMixin {
       await session.start(path.join(pluginPath, 'byteStore'), sdkPath),
       isFalse,
     );
+    expect(
+      notificationManager.pluginErrors.first,
+      startsWith(
+        'An error occurred while executing an analyzer plugin: Plugin is not '
+        'compatible.',
+      ),
+    );
   }
 
   Future<void> test_start_running() async {
@@ -933,6 +942,13 @@ class TestNotificationManager implements AbstractNotificationManager {
   Map<String, Map<String, List<AnalysisError>>> recordedErrors =
       <String, Map<String, List<AnalysisError>>>{};
 
+  List<String> pluginErrors = [];
+
+  @override
+  void handlePluginError(String message) {
+    pluginErrors.add(message);
+  }
+
   @override
   void handlePluginNotification(String pluginId, Notification notification) {
     notifications.add(notification);