Check filter text before setting repos

This prevents a race condition where a longer response can resolve after
an earlier one. This treatment is similar to that used in
gr-autocomplete.

Bug: Issue 8593
Change-Id: Ic581d1e0eb05cab97d9293d88b237c3bdd79a4f9

polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.js

@@ -63,7 +63,10 @@
         type: Boolean,
         value: true,
       },
-      _filter: String,
+      _filter: {
+        type: String,
+        value: '',
+      },
     },
 
     behaviors: [
@@ -115,7 +118,8 @@
       this._repos = [];
       return this.$.restAPI.getRepos(filter, reposPerPage, offset)
           .then(repos => {
-            if (!repos) { return; }
+            // Late response.
+            if (filter !== this._filter || !repos) { return; }
             this._repos = Object.keys(repos)
              .map(key => {
                const repo = repos[key];

polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list_test.html

@@ -56,6 +56,7 @@ limitations under the License.
 
     setup(() => {
       sandbox = sinon.sandbox.create();
+      sandbox.stub(page, 'show');
       element = fixture('basic');
       counter = 0;
     });
@@ -118,6 +119,11 @@ limitations under the License.
     });
 
     suite('filter', () => {
+      setup(() => {
+        repos = _.times(25, repoGenerator);
+        reposFiltered = _.times(1, repoGenerator);
+      });
+
       test('_paramsChanged', done => {
         sandbox.stub(element.$.restAPI, 'getRepos', () => {
           return Promise.resolve(repos);
@@ -132,6 +138,19 @@ limitations under the License.
           done();
         });
       });
+
+      test('latest repos requested are always set', done => {
+        const repoStub = sandbox.stub(element.$.restAPI, 'getRepos');
+        repoStub.withArgs('test').returns(Promise.resolve(repos));
+        repoStub.withArgs('filter').returns(Promise.resolve(reposFiltered));
+        element._filter = 'test';
+
+        // Repos are not set because the element._filter differs.
+        element._getRepos('filter', 25, 0).then(() => {
+          assert.deepEqual(element._repos, []);
+          done();
+        });
+      });
     });
 
     suite('loading', () => {