diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html
index dc6404232e..b2c3e18852 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html
@@ -267,9 +267,9 @@ limitations under the License.
             [[_computeFileStatus(file.status)]]
           </div>
           <span
-              data-url="[[_computeDiffURL(change, patchRange, file.__path)]]"
+              data-url="[[_computeDiffURL(change, patchRange.patchNum, patchRange.basePatchNum, file.__path)]]"
               class$="[[_computePathClass(file.__path, _expandedFilePaths.*)]]">
-            <a href$="[[_computeDiffURL(change, patchRange, file.__path)]]">
+            <a href$="[[_computeDiffURL(change, patchRange.patchNum, patchRange.basePatchNum, file.__path)]]">
               <span title$="[[_computeFileDisplayName(file.__path)]]"
                   class="fullFileName">
                 [[_computeFileDisplayName(file.__path)]]
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
index 856071724e..c1f8c6cf2c 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js
@@ -662,9 +662,8 @@
       return status || 'M';
     },
 
-    _computeDiffURL(change, patchRange, path) {
-      return Gerrit.Nav.getUrlForDiff(change, path, patchRange.patchNum,
-          patchRange.basePatchNum);
+    _computeDiffURL(change, patchNum, basePatchNum, path) {
+      return Gerrit.Nav.getUrlForDiff(change, path, patchNum, basePatchNum);
     },
 
     _computeFileDisplayName(path) {
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.html b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.html
index 9be19a7b75..70f7e2b54f 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.html
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.html
@@ -988,6 +988,21 @@ limitations under the License.
       element.flushDebouncer('loading-change');
       assert.isFalse(element.classList.contains('loading'));
     });
+
+    test('no execute _computeDiffURL before patchNum is knwon', done => {
+      const urlStub = sandbox.stub(element, '_computeDiffURL');
+      element.change = {_number: 123};
+      element.patchRange = {patchNum: undefined, basePatchNum: 'PARENT'};
+      element._files = [{__path: 'foo/bar.cpp'}];
+      flush(() => {
+        assert.isFalse(urlStub.called);
+        element.set('patchRange.patchNum', 4);
+        flush(() => {
+          assert.isTrue(urlStub.called);
+          done();
+        });
+      });
+    });
   });
 
   suite('gr-file-list inline diff tests', () => {