Only save if task changed

src/main/java/com/todoroo/astrid/activity/TaskEditFragment.java

@@ -332,7 +332,9 @@ public final class TaskEditFragment extends InjectingFragment implements EditNot
 
     /** Save task model from values in UI components */
     public void save() {
-        for (TaskEditControlFragment fragment : getFragments()) {
+        List<TaskEditControlFragment> fragments = getFragments();
+        if (hasChanges(fragments)) {
+            for (TaskEditControlFragment fragment : fragments) {
                 fragment.apply(model);
             }
             taskService.save(model);
@@ -349,9 +351,11 @@ public final class TaskEditFragment extends InjectingFragment implements EditNot
             if (isNewTask) {
                 tla.getTaskListFragment().onTaskCreated(model.getId(), model.getUuid());
             }
-
             removeExtrasFromIntent(getActivity().getIntent());
             callback.taskEditFinished();
+        } else {
+            discard();
+        }
     }
 
     private EditTitleControlSet getEditTitleControlSet() {
@@ -386,12 +390,17 @@ public final class TaskEditFragment extends InjectingFragment implements EditNot
      * ======================================================================
      */
 
-    public void discardButtonClick() {
+    private boolean hasChanges(List<TaskEditControlFragment> fragments) {
-        boolean hasChanges = false;
+        for (TaskEditControlFragment fragment : fragments) {
-        for (TaskEditControlFragment fragment : getFragments()) {
+            if (fragment.hasChanges(model)) {
-            hasChanges |= fragment.hasChanges(model);
+                return true;
+            }
+        }
+        return false;
     }
-        if (hasChanges) {
+
+    public void discardButtonClick() {
+        if (hasChanges(getFragments())) {
             dialogBuilder.newMessageDialog(R.string.discard_confirmation)
                     .setPositiveButton(R.string.keep_editing, null)
                     .setNegativeButton(R.string.discard, new DialogInterface.OnClickListener() {