Do not try to upload/submit when uploaded file is moved or deleted.

openassessment/xblock/static/js/spec/lms/oa_response.js

@@ -702,4 +702,20 @@ describe("OpenAssessment.ResponseView", function() {
         expect(view.files).toEqual(null);
         expect($(view.element).find('.file__upload').first().is(':disabled')).toEqual(true);
     });
+
+     it("prevents user from uploading files when file is moved or deleted", function() {
+
+         spyOn(view.baseView, 'toggleActionError').and.callThrough();
+         view.fileUploadResponse = 'optional';
+
+         var file = [{type: 'image/jpeg', size: 0, name: 'picture.jpg', data: ''}];
+         view.prepareUpload(file, 'image', ['test1']);
+         view.uploadFiles();
+
+         expect(view.hasAllUploadFiles()).toEqual(false);
+         expect(view.baseView.toggleActionError).toHaveBeenCalledWith('upload',
+            "Your file " + file[0].name + " has been deleted or path has been changed.");
+
+
+    });
 });
\ No newline at end of file

openassessment/xblock/static/js/src/lms/oa_response.js

@@ -125,6 +125,7 @@ OpenAssessment.ResponseView.prototype = {
                 eventObject.preventDefault();
                 var previouslyUploadedFiles = sel.find('.submission__answer__file').length ? true : false;
                 $('.submission__answer__display__file', view.element).removeClass('is--hidden');
+                if (view.hasAllUploadFiles()) {
                     if (previouslyUploadedFiles) {
                         var msg = gettext('After you upload new files all your previously uploaded files will be overwritten. Continue?');  // jscs:ignore maximumLineLength
                         if (confirm(msg)) {
@@ -134,6 +135,7 @@ OpenAssessment.ResponseView.prototype = {
                         view.uploadFiles();
                     }
                 }
+            }
         );
     },
 
@@ -267,7 +269,24 @@ OpenAssessment.ResponseView.prototype = {
     hasPendingUploadFiles: function() {
         return this.files !== null && !this.filesUploaded;
     },
-
+    /**
+     Check if there is a selected file moved or deleted before uploading
+     Returns:
+     boolean: if we have deleted/moved files or not.
+     **/
+    hasAllUploadFiles: function() {
+        for (var i = 0; i < this.files.length; i++) {
+            var file = this.files[i];
+            if (file.size === 0) {
+                this.baseView.toggleActionError(
+                    'upload',
+                    gettext("Your file " + file.name + " has been deleted or path has been changed."));
+                this.submitEnabled(true);
+                return false;
+            }
+        }
+        return true;
+    },
     /**
      Set the save status message.
      Retrieve the save status message.
@@ -431,15 +450,17 @@ OpenAssessment.ResponseView.prototype = {
         var fileDefer = $.Deferred();
 
         if (view.hasPendingUploadFiles()) {
+            if (!view.hasAllUploadFiles()) {
+                return;
+            }
+            else {
                 var msg = gettext('Do you want to upload your file before submitting?');
                 if (confirm(msg)) {
                     fileDefer = view.uploadFiles();
                     if (fileDefer === false) {
                         return;
                     }
-            } else {
-                view.submitEnabled(true);
-                return;
+                }
             }
         } else {
             fileDefer.resolve();