Check for reset during 'await' in refactoring manager.

pkg/analysis_server/lib/src/edit/edit_domain.dart

Index: pkg/analysis_server/lib/src/edit/edit_domain.dart
diff --git a/pkg/analysis_server/lib/src/edit/edit_domain.dart b/pkg/analysis_server/lib/src/edit/edit_domain.dart
index 3213537a6c4fa338dbed956c171fc1056262927c..fa0f8497469537cbe3cbdae0ab624e4c682d959f 100644
--- a/pkg/analysis_server/lib/src/edit/edit_domain.dart
+++ b/pkg/analysis_server/lib/src/edit/edit_domain.dart
@@ -32,6 +32,10 @@ bool test_simulateRefactoringException_change = false;
 bool test_simulateRefactoringException_final = false;
 bool test_simulateRefactoringException_init = false;
 
+bool test_simulateRefactoringReset_afterCreateChange = false;
+bool test_simulateRefactoringReset_afterFinalConditions = false;
+bool test_simulateRefactoringReset_afterInitialConditions = false;
+
 /**
  * Instances of the class [EditDomainHandler] implement a [RequestHandler]
  * that handles requests in the edit domain.
@@ -452,6 +456,7 @@ class _RefactoringManager {
       }
       // validation and create change
       finalStatus = await refactoring.checkFinalConditions();
+      _checkForReset_afterFinalConditions();
       if (_hasFatalError) {
         _sendResultResponse();
         return;
@@ -463,15 +468,47 @@ class _RefactoringManager {
       // create change
       result.change = await refactoring.createChange();
       result.potentialEdits = nullIfEmpty(refactoring.potentialEditIds);
+      _checkForReset_afterCreateChange();
       _sendResultResponse();
     }, onError: (exception, stackTrace) {
-      server.instrumentationService.logException(exception, stackTrace);
-      server.sendResponse(
-          new Response.serverError(_request, exception, stackTrace));
+      if (exception is _ResetError) {
+        cancel();
+      } else {
+        server.instrumentationService.logException(exception, stackTrace);
+        server.sendResponse(
+            new Response.serverError(_request, exception, stackTrace));
+      }
       _reset();
     });
   }
 
+  void _checkForReset_afterCreateChange() {
+    if (test_simulateRefactoringReset_afterCreateChange) {
+      _reset();
+    }
+    if (refactoring == null) {
+      throw new _ResetError();
+    }
+  }
+
+  void _checkForReset_afterFinalConditions() {
+    if (test_simulateRefactoringReset_afterFinalConditions) {
+      _reset();
+    }
+    if (refactoring == null) {
+      throw new _ResetError();
+    }
+  }
+
+  void _checkForReset_afterInitialConditions() {
+    if (test_simulateRefactoringReset_afterInitialConditions) {
+      _reset();
+    }
+    if (refactoring == null) {
+      throw new _ResetError();
+    }
+  }
+
   /**
    * Initializes this context to perform a refactoring with the specified
    * parameters. The existing [Refactoring] is reused or created as needed.
@@ -581,6 +618,7 @@ class _RefactoringManager {
     }
     // check initial conditions
     initStatus = await refactoring.checkInitialConditions();
+    _checkForReset_afterInitialConditions();
     if (refactoring is ExtractLocalRefactoring) {
       ExtractLocalRefactoring refactoring = this.refactoring;
       ExtractLocalVariableFeedback feedback = this.feedback;
@@ -692,3 +730,9 @@ class _RefactoringManager {
     return new RefactoringStatus();
   }
 }
+
+/**
+ * [_RefactoringManager] throws instances of this class internally to stop
+ * processing in a manager that was reset.
+ */
+class _ResetError {}