Improve error messages experience in pipeline editor

app/assets/javascripts/pipeline_editor/pipeline_editor_app.vue

@@ -247,10 +247,14 @@ export default {
       await this.$apollo.queries.initialCiFileContent.refetch();
     },
     reportFailure(type, reasons = []) {
-      window.scrollTo({ top: 0, behavior: 'smooth' });
-      this.showFailure = true;
-      this.failureType = type;
-      this.failureReasons = reasons;
+      const isCurrentFailure = this.failureType === type && this.failureReasons[0] === reasons[0];
+
+      if (!isCurrentFailure) {
+        this.showFailure = true;
+        this.failureType = type;
+        this.failureReasons = reasons;
+        window.scrollTo({ top: 0, behavior: 'smooth' });
+      }
     },
     reportSuccess(type) {
       window.scrollTo({ top: 0, behavior: 'smooth' });

spec/frontend/pipeline_editor/pipeline_editor_app_spec.js

@@ -8,7 +8,7 @@ import waitForPromises from 'helpers/wait_for_promises';
 import PipelineEditorTabs from '~/pipeline_editor/components/pipeline_editor_tabs.vue';
 import PipelineEditorEmptyState from '~/pipeline_editor/components/ui/pipeline_editor_empty_state.vue';
 import PipelineEditorMessages from '~/pipeline_editor/components/ui/pipeline_editor_messages.vue';
-import { COMMIT_SUCCESS, COMMIT_FAILURE } from '~/pipeline_editor/constants';
+import { COMMIT_SUCCESS, COMMIT_FAILURE, LOAD_FAILURE_UNKNOWN } from '~/pipeline_editor/constants';
 import getBlobContent from '~/pipeline_editor/graphql/queries/blob_content.graphql';
 import getCiConfigData from '~/pipeline_editor/graphql/queries/ci_config.graphql';
 import getTemplate from '~/pipeline_editor/graphql/queries/get_starter_template.query.graphql';
@@ -412,6 +412,94 @@ describe('Pipeline editor app component', () => {
     });
   });
 
+  describe('when multiple errors occurs in a row', () => {
+    const updateFailureMessage = 'The GitLab CI configuration could not be updated.';
+    const unknownFailureMessage = 'The CI configuration was not loaded, please try again.';
+    const unknownReasons = ['Commit failed'];
+    const alertErrorMessage = `${updateFailureMessage} ${unknownReasons[0]}`;
+
+    const emitError = (type = COMMIT_FAILURE, reasons = unknownReasons) =>
+      findEditorHome().vm.$emit('showError', {
+        type,
+        reasons,
+      });
+
+    beforeEach(async () => {
+      mockBlobContentData.mockResolvedValue(mockBlobContentQueryResponse);
+      mockCiConfigData.mockResolvedValue(mockCiConfigQueryResponse);
+      mockLatestCommitShaQuery.mockResolvedValue(mockCommitShaResults);
+
+      window.scrollTo = jest.fn();
+
+      await createComponentWithApollo({ stubs: { PipelineEditorMessages } });
+      await emitError();
+    });
+
+    it('shows an error message for the first error', () => {
+      expect(findAlert().text()).toMatchInterpolatedText(alertErrorMessage);
+    });
+
+    it('scrolls to the top of the page to bring attention to the error message', () => {
+      expect(window.scrollTo).toHaveBeenCalledWith({ top: 0, behavior: 'smooth' });
+      expect(window.scrollTo).toHaveBeenCalledTimes(1);
+    });
+
+    it('does not scroll to the top of the page if the same error occur multiple times in a row', async () => {
+      await emitError();
+
+      expect(window.scrollTo).toHaveBeenCalledTimes(1);
+      expect(findAlert().text()).toMatchInterpolatedText(alertErrorMessage);
+    });
+
+    it('scrolls to the top if the error is different', async () => {
+      await emitError(LOAD_FAILURE_UNKNOWN, []);
+
+      expect(findAlert().text()).toMatchInterpolatedText(unknownFailureMessage);
+      expect(window.scrollTo).toHaveBeenCalledTimes(2);
+    });
+
+    describe('when a user dismiss the alert', () => {
+      beforeEach(async () => {
+        await findAlert().vm.$emit('dismiss');
+      });
+
+      it('shows an error if the type is the same, but the reason is different', async () => {
+        const newReason = 'Something broke';
+
+        await emitError(COMMIT_FAILURE, [newReason]);
+
+        expect(window.scrollTo).toHaveBeenCalledTimes(2);
+        expect(findAlert().text()).toMatchInterpolatedText(`${updateFailureMessage} ${newReason}`);
+      });
+
+      it('does not show an error or scroll if a new error with the same type occurs', async () => {
+        await emitError();
+
+        expect(window.scrollTo).toHaveBeenCalledTimes(1);
+        expect(findAlert().exists()).toBe(false);
+      });
+
+      it('it shows an error and scroll when a new type is emitted', async () => {
+        await emitError(LOAD_FAILURE_UNKNOWN, []);
+
+        expect(window.scrollTo).toHaveBeenCalledTimes(2);
+        expect(findAlert().text()).toMatchInterpolatedText(unknownFailureMessage);
+      });
+
+      it('it shows an error and scroll if a previously shown type happen again', async () => {
+        await emitError(LOAD_FAILURE_UNKNOWN, []);
+
+        expect(window.scrollTo).toHaveBeenCalledTimes(2);
+        expect(findAlert().text()).toMatchInterpolatedText(unknownFailureMessage);
+
+        await emitError();
+
+        expect(window.scrollTo).toHaveBeenCalledTimes(3);
+        expect(findAlert().text()).toMatchInterpolatedText(alertErrorMessage);
+      });
+    });
+  });
+
   describe('when add_new_config_file query param is present', () => {
     const originalLocation = window.location.href;