Fixes issue where discussions would not be assigned with batch diffs

This fixes an issue where discussions can sometimes take longer
to load and then won't be assigned to the lines in diffs

app/assets/javascripts/diffs/components/app.vue

@@ -163,9 +163,6 @@ export default {
     },
     isLoading: 'adjustView',
     showTreeList: 'adjustView',
-    retrievingBatches(newVal) {
-      if (!newVal) this.unwatchDiscussions();
-    },
   },
   mounted() {
     this.setBaseConfig({
@@ -198,6 +195,16 @@ export default {
       () => `${this.diffFiles.length}:${this.$store.state.notes.discussions.length}`,
       () => this.setDiscussions(),
     );
+
+    this.unwatchRetrievingBatches = this.$watch(
+      () => `${this.retrievingBatches}:${this.$store.state.notes.discussions.length}`,
+      () => {
+        if (!this.retrievingBatches && this.$store.state.notes.discussions.length) {
+          this.unwatchDiscussions();
+          this.unwatchRetrievingBatches();
+        }
+      },
+    );
   },
   beforeDestroy() {
     eventHub.$off('fetchDiffData', this.fetchData);

spec/javascripts/diffs/components/app_spec.js

@@ -87,6 +87,7 @@ describe('diffs/components/app', () => {
       spyOn(wrapper.vm, 'setDiscussions');
       spyOn(wrapper.vm, 'startRenderDiffsQueue');
       spyOn(wrapper.vm, 'unwatchDiscussions');
+      spyOn(wrapper.vm, 'unwatchRetrievingBatches');
       store.state.diffs.retrievingBatches = true;
       store.state.diffs.diffFiles = [];
       wrapper.vm.$nextTick(done);
@@ -240,6 +241,7 @@ describe('diffs/components/app', () => {
         expect(wrapper.vm.fetchDiffFilesBatch).not.toHaveBeenCalled();
         expect(wrapper.vm.unwatchDiscussions).toHaveBeenCalled();
         expect(wrapper.vm.diffFilesLength).toEqual(100);
+        expect(wrapper.vm.unwatchRetrievingBatches).toHaveBeenCalled();
 
         done();
       });
@@ -258,6 +260,7 @@ describe('diffs/components/app', () => {
         expect(wrapper.vm.fetchDiffFilesBatch).toHaveBeenCalled();
         expect(wrapper.vm.unwatchDiscussions).toHaveBeenCalled();
         expect(wrapper.vm.diffFilesLength).toEqual(100);
+        expect(wrapper.vm.unwatchRetrievingBatches).toHaveBeenCalled();
         done();
       });
     });
@@ -274,6 +277,7 @@ describe('diffs/components/app', () => {
         expect(wrapper.vm.fetchDiffFilesBatch).toHaveBeenCalled();
         expect(wrapper.vm.unwatchDiscussions).toHaveBeenCalled();
         expect(wrapper.vm.diffFilesLength).toEqual(100);
+        expect(wrapper.vm.unwatchRetrievingBatches).toHaveBeenCalled();
         done();
       });
     });