Merge branch 'mr-discussion-expanding-bug-fixes' into 'master'

Fixed hidden truncated diff lines not showing when expanded

See merge request gitlab-org/gitlab-ce!21801

app/assets/javascripts/notes/stores/mutations.js

@@ -100,7 +100,10 @@ export default {
 
     discussionsData.forEach(discussion => {
       if (discussion.diff_file) {
-        Object.assign(discussion, { fileHash: discussion.diff_file.file_hash });
+        Object.assign(discussion, {
+          fileHash: discussion.diff_file.file_hash,
+          truncated_diff_lines: discussion.truncated_diff_lines || [],
+        });
       }
 
       // To support legacy notes, should be very rare case.

spec/javascripts/notes/stores/mutation_spec.js

@@ -156,6 +156,41 @@ describe('Notes Store mutations', () => {
       expect(state.discussions[2].notes[0].note).toBe(legacyNote.notes[1].note);
       expect(state.discussions.length).toEqual(3);
     });
+
+    it('adds truncated_diff_lines if discussion is a diffFile', () => {
+      const state = {
+        discussions: [],
+      };
+
+      mutations.SET_INITIAL_DISCUSSIONS(state, [
+        {
+          ...note,
+          diff_file: {
+            file_hash: 'a',
+          },
+          truncated_diff_lines: ['a'],
+        },
+      ]);
+
+      expect(state.discussions[0].truncated_diff_lines).toEqual(['a']);
+    });
+
+    it('adds empty truncated_diff_lines when not in discussion', () => {
+      const state = {
+        discussions: [],
+      };
+
+      mutations.SET_INITIAL_DISCUSSIONS(state, [
+        {
+          ...note,
+          diff_file: {
+            file_hash: 'a',
+          },
+        },
+      ]);
+
+      expect(state.discussions[0].truncated_diff_lines).toEqual([]);
+    });
   });
 
   describe('SET_LAST_FETCHED_AT', () => {