diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
index 8a89937..2a00425 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
@@ -50,6 +50,9 @@
 
       stub('gr-rest-api-interface', {
         getLoggedIn() { return Promise.resolve(false); },
+        getDiff() {
+          return Promise.resolve(mockDiffResponse.diffResponse);
+        },
       });
 
       const fixtureElems = fixture('basic');
@@ -60,15 +63,12 @@
       // Register the diff with the cursor.
       cursorElement.push('diffs', diffElement);
 
+      diffElement.patchRange = {basePatchNum: 1, patchNum: 2};
       diffElement.comments = {left: [], right: []};
       diffElement.$.restAPI.getDiffPreferences().then(prefs => {
         diffElement.prefs = prefs;
       });
 
-      sandbox.stub(diffElement, '_getDiff', () => {
-        return Promise.resolve(mockDiffResponse.diffResponse);
-      });
-
       const setupDone = () => {
         cursorElement._updateStops();
         cursorElement.moveToFirstChunk();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
index 8e975f4..cb37d0d 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
@@ -192,15 +192,20 @@
         font-size: var(--font-size, var(--font-size-normal));
         padding: 0.5em 0 0.5em 4em;
       }
+      #loadingError,
       #sizeWarning {
         display: none;
         margin: 1em auto;
         max-width: 60em;
         text-align: center;
       }
+      #loadingError {
+        color: var(--error-text-color);
+      }
       #sizeWarning gr-button {
         margin: 1em;
       }
+      #loadingError.showError,
       #sizeWarning.warn {
         display: block;
       }
@@ -299,6 +304,9 @@
     <div class$="[[_computeNewlineWarningClass(_newlineWarning, _loading)]]">
       [[_newlineWarning]]
     </div>
+    <div id="loadingError" class$="[[_computeErrorClass(_showError)]]">
+      [[_errorMessage]]
+    </div>
     <div id="sizeWarning" class$="[[_computeWarningClass(_showWarning)]]">
       <p>
         Prevented render because "Whole file" is enabled and this diff is very
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
index 4b19e67..4032cec 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
@@ -123,6 +123,14 @@
        */
       lineOfInterest: Object,
 
+      /**
+       * If the diff fails to load, show the failure message in the diff rather
+       * than bubbling the error up to the whole page. This is useful for when
+       * loading inline diffs because one diff failing need not mark the whole
+       * page with a failure.
+       */
+      showLoadFailure: Boolean,
+
       _loading: {
         type: Boolean,
         value: false,
@@ -162,6 +170,12 @@
 
       _showWarning: Boolean,
 
+      _showError: {
+        type: Boolean,
+        value: false,
+      },
+      _errorMessage: String,
+
       /** @type {?Object} */
       _blame: {
         type: Object,
@@ -224,16 +238,23 @@
       this.clearBlame();
       this._safetyBypass = null;
       this._showWarning = false;
+      this._showError = false;
       this.clearDiffContent();
 
-      const promises = [];
+      const diffRequest = this._getDiff();
 
-      promises.push(this._getDiff().then(diff => {
-        this._diff = diff;
+      const assetRequest = diffRequest.then(diff => {
+        // If the diff is null, then it's failed to load.
+        if (!diff) { return null; }
+
         return this._loadDiffAssets();
-      }));
+      });
 
-      return Promise.all(promises).then(() => {
+      return Promise.all([diffRequest, assetRequest]).then(results => {
+        const diff = results[0];
+        if (!diff) {
+          return Promise.resolve();
+        }
         if (this.prefs) {
           return this._renderDiffTable();
         }
@@ -727,34 +748,59 @@
         this.fire('server-error', {response});
         return;
       }
+
+      if (this.showLoadFailure) {
+        this._errorMessage = [
+          'Encountered error when loading the diff:',
+          response.status,
+          response.statusText,
+        ].join(' ');
+        this._showError = true;
+        return;
+      }
+
       this.fire('page-error', {response});
     },
 
     /** @return {!Promise<!Object>} */
     _getDiff() {
-      return this.$.restAPI.getDiff(
-          this.changeNum,
-          this.patchRange.basePatchNum,
-          this.patchRange.patchNum,
-          this.path,
-          this._handleGetDiffError.bind(this)).then(diff => {
+      // Wrap the diff request in a new promise so that the error handler
+      // rejects the promise, allowing the error to be handled in the .catch.
+      const request = new Promise((resolve, reject) => {
+        this.$.restAPI.getDiff(
+            this.changeNum,
+            this.patchRange.basePatchNum,
+            this.patchRange.patchNum,
+            this.path,
+            reject)
+            .then(resolve);
+      });
+
+      return request
+          .then(diff => {
+            this.filesWeblinks = this._getFilesWeblinks(diff);
+            this._diff = diff;
             this._reportDiff(diff);
-            if (!this.commitRange) {
-              this.filesWeblinks = {};
-              return diff;
-            }
-            this.filesWeblinks = {
-              meta_a: Gerrit.Nav.getFileWebLinks(
-                  this.projectName, this.commitRange.baseCommit, this.path,
-                  {weblinks: diff && diff.meta_a && diff.meta_a.web_links}),
-              meta_b: Gerrit.Nav.getFileWebLinks(
-                  this.projectName, this.commitRange.commit, this.path,
-                  {weblinks: diff && diff.meta_b && diff.meta_b.web_links}),
-            };
             return diff;
+          })
+          .catch(e => {
+            this._handleGetDiffError(e);
+            return null;
           });
     },
 
+    _getFilesWeblinks(diff) {
+      if (!this.commitRange) { return {}; }
+      return {
+        meta_a: Gerrit.Nav.getFileWebLinks(
+            this.projectName, this.commitRange.baseCommit, this.path,
+            {weblinks: diff && diff.meta_a && diff.meta_a.web_links}),
+        meta_b: Gerrit.Nav.getFileWebLinks(
+            this.projectName, this.commitRange.commit, this.path,
+            {weblinks: diff && diff.meta_b && diff.meta_b.web_links}),
+      };
+    },
+
     /**
      * Report info about the diff response.
      */
@@ -890,6 +936,11 @@
       return showWarning ? 'warn' : '';
     },
 
+    /** @return {string} */
+    _computeErrorClass(showError) {
+      return showError ? 'showError' : '';
+    },
+
     /**
      * @return {number|null}
      */
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
index b98602f..2821dde 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
@@ -410,7 +410,6 @@
       suite('image diffs', () => {
         let mockFile1;
         let mockFile2;
-        const stubs = [];
         setup(() => {
           mockFile1 = {
             body: 'Qk06AAAAAAAAADYAAAAoAAAAAQAAAP////8BACAAAAAAAAAAAAATCwAAE' +
@@ -445,18 +444,18 @@
           };
           const mockComments = {baseComments: [], comments: []};
 
-          stubs.push(sandbox.stub(element.$.restAPI, 'getCommitInfo',
-              () => Promise.resolve(mockCommit)));
-          stubs.push(sandbox.stub(element.$.restAPI,
+          sandbox.stub(element.$.restAPI, 'getCommitInfo')
+              .returns(Promise.resolve(mockCommit));
+          sandbox.stub(element.$.restAPI,
               'getB64FileContents',
               (changeId, patchNum, path, opt_parentIndex) => {
                 return Promise.resolve(opt_parentIndex === 1 ? mockFile1 :
                     mockFile2);
-              }));
-          stubs.push(sandbox.stub(element.$.restAPI, '_getDiffComments',
-              () => Promise.resolve(mockComments)));
-          stubs.push(sandbox.stub(element.$.restAPI, 'getDiffDrafts',
-              () => Promise.resolve(mockComments)));
+              });
+          sandbox.stub(element.$.restAPI, '_getDiffComments')
+              .returns(Promise.resolve(mockComments));
+          sandbox.stub(element.$.restAPI, 'getDiffDrafts')
+              .returns(Promise.resolve(mockComments));
 
           element.patchRange = {basePatchNum: 'PARENT', patchNum: 1};
           element.comments = {left: [], right: []};
@@ -479,8 +478,8 @@
             content: [{skip: 66}],
             binary: true,
           };
-          stubs.push(sandbox.stub(element, '_getDiff',
-              () => Promise.resolve(mockDiff)));
+          sandbox.stub(element.$.restAPI, 'getDiff')
+              .returns(Promise.resolve(mockDiff));
 
           const rendered = () => {
             // Recognizes that it should be an image diff.
@@ -559,8 +558,8 @@
             content: [{skip: 66}],
             binary: true,
           };
-          stubs.push(sandbox.stub(element, '_getDiff',
-              () => Promise.resolve(mockDiff)));
+          sandbox.stub(element.$.restAPI, 'getDiff')
+              .returns(Promise.resolve(mockDiff));
 
           const rendered = () => {
             // Recognizes that it should be an image diff.
@@ -640,8 +639,8 @@
             content: [{skip: 66}],
             binary: true,
           };
-          stubs.push(sandbox.stub(element, '_getDiff',
-              () => Promise.resolve(mockDiff)));
+          sandbox.stub(element.$.restAPI, 'getDiff')
+              .returns(Promise.resolve(mockDiff));
 
           element.addEventListener('render', () => {
             // Recognizes that it should be an image diff.
@@ -679,8 +678,8 @@
             content: [{skip: 66}],
             binary: true,
           };
-          stubs.push(sandbox.stub(element, '_getDiff',
-              () => Promise.resolve(mockDiff)));
+          sandbox.stub(element.$.restAPI, 'getDiff')
+              .returns(Promise.resolve(mockDiff));
 
           element.addEventListener('render', () => {
             // Recognizes that it should be an image diff.
@@ -720,8 +719,8 @@
           };
           mockFile1.type = 'image/jpeg-evil';
 
-          stubs.push(sandbox.stub(element, '_getDiff',
-              () => Promise.resolve(mockDiff)));
+          sandbox.stub(element.$.restAPI, 'getDiff')
+              .returns(Promise.resolve(mockDiff));
 
           element.addEventListener('render', () => {
             // Recognizes that it should be an image diff.
@@ -793,6 +792,55 @@
         element._getDiff().then(done);
       });
 
+      test('_getDiff resolves as null on error', () => {
+        const onErrStub = sandbox.stub(element, '_handleGetDiffError');
+        const error = {ok: false, status: 500};
+        sandbox.stub(element.$.restAPI, 'getDiff',
+            (changeNum, basePatchNum, patchNum, path, onErr) => {
+              onErr(error);
+            });
+        return element._getDiff().then(diff => {
+          assert.isNull(diff);
+          assert.isTrue(onErrStub.calledOnce);
+        });
+      });
+
+      suite('_handleGetDiffError', () => {
+        let serverErrorStub;
+        let pageErrorStub;
+
+        setup(() => {
+          serverErrorStub = sinon.stub();
+          element.addEventListener('server-error', serverErrorStub);
+          pageErrorStub = sinon.stub();
+          element.addEventListener('page-error', pageErrorStub);
+        });
+
+        test('page error on HTTP-409', () => {
+          element._handleGetDiffError({status: 409});
+          assert.isTrue(serverErrorStub.calledOnce);
+          assert.isFalse(pageErrorStub.called);
+          assert.isFalse(element._showError);
+        });
+
+        test('server error on non-HTTP-409', () => {
+          element._handleGetDiffError({status: 500});
+          assert.isFalse(serverErrorStub.called);
+          assert.isTrue(pageErrorStub.calledOnce);
+          assert.isFalse(element._showError);
+        });
+
+        test('error message if showLoadFailure', () => {
+          element.showLoadFailure = true;
+          element._handleGetDiffError({status: 500, statusText: 'Failure!'});
+          assert.isFalse(serverErrorStub.called);
+          assert.isFalse(pageErrorStub.called);
+          assert.isTrue(element._showError);
+          assert.equal(element._errorMessage,
+              'Encountered error when loading the diff: 500 Failure!');
+        });
+      });
+
       suite('getCursorStops', () => {
         const setupDiff = function() {
           const mock = document.createElement('mock-diff-response');