Failing gracefully

pkg/docgen/lib/docgen.dart

Index: pkg/docgen/lib/docgen.dart
diff --git a/pkg/docgen/lib/docgen.dart b/pkg/docgen/lib/docgen.dart
index af8540b49827aadeb237727fce58a822b80ea6e9..70f6ea3a7c9b2eafe20b2066297cd26bdb256798 100644
--- a/pkg/docgen/lib/docgen.dart
+++ b/pkg/docgen/lib/docgen.dart
@@ -182,7 +182,15 @@ Future<MirrorSystem> _getMirrorSystemHelper(List<String> libraries,
   });
   return dart2js.analyze(librariesUri, libraryUri, packageUri,
       provider.readStringFromUri, diagnosticHandler,
-      ['--preserve-comments', '--categories=Client,Server']);
+      ['--preserve-comments', '--categories=Client,Server'])
+      ..catchError((error) {
+        logger.severe('Error: Failed to create mirror system. ');
+        // TODO(janicejl): Use the stack trace package when bug is resolved. 
+        // Currently, a string is thrown when it fails to create a mirror 
+        // system, and it is not possible to use the stack trace. BUG(#11622)
+        // To avoid printing the stack trace. 
+        exit(1);
+      });
 }
 
 /**