Add latest changes from gitlab-org/gitlab@master

12 files changed, 328 insertions, 151 deletions

diff --git a/app/assets/javascripts/actioncable_link.js b/app/assets/javascripts/actioncable_link.js
new file mode 100644
index 00000000000..4c642db2f3c
--- /dev/null
+++ b/app/assets/javascripts/actioncable_link.js
@@ -0,0 +1,40 @@
+import { ApolloLink, Observable } from 'apollo-link';
+import { print } from 'graphql';
+import cable from '~/actioncable_consumer';
+import { uuids } from '~/diffs/utils/uuids';
+
+export default class ActionCableLink extends ApolloLink {
+  // eslint-disable-next-line class-methods-use-this
+  request(operation) {
+    return new Observable((observer) => {
+      const subscription = cable.subscriptions.create(
+        {
+          channel: 'GraphqlChannel',
+          query: operation.query ? print(operation.query) : null,
+          variables: operation.variables,
+          operationName: operation.operationName,
+          nonce: uuids()[0],
+        },
+        {
+          received(data) {
+            if (data.errors) {
+              observer.error(data.errors);
+            } else if (data.result) {
+              observer.next(data.result);
+            }
+
+            if (!data.more) {
+              observer.complete();
+            }
+          },
+        },
+      );
+
+      return {
+        unsubscribe() {
+          subscription.unsubscribe();
+        },
+      };
+    });
+  }
+}
diff --git a/app/assets/javascripts/gfm_auto_complete.js b/app/assets/javascripts/gfm_auto_complete.js
index 22f88b1caa7..ee8384f734d 100644
--- a/app/assets/javascripts/gfm_auto_complete.js
+++ b/app/assets/javascripts/gfm_auto_complete.js
@@ -238,10 +238,13 @@ class GfmAutoComplete {
     const MEMBER_COMMAND = {
       ASSIGN: '/assign',
       UNASSIGN: '/unassign',
+      ASSIGN_REVIEWER: '/assign_reviewer',
+      UNASSIGN_REVIEWER: '/unassign_reviewer',
       REASSIGN: '/reassign',
       CC: '/cc',
     };
     let assignees = [];
+    let reviewers = [];
     let command = '';
 
     // Team Members
@@ -286,9 +289,11 @@ class GfmAutoComplete {
             return null;
           });
 
-          // Cache assignees list for easier filtering later
+          // Cache assignees & reviewers list for easier filtering later
           assignees =
             SidebarMediator.singleton?.store?.assignees?.map(createMemberSearchString) || [];
+          reviewers =
+            SidebarMediator.singleton?.store?.reviewers?.map(createMemberSearchString) || [];
 
           const match = GfmAutoComplete.defaultMatcher(flag, subtext, this.app.controllers);
           return match && match.length ? match[1] : null;
@@ -309,6 +314,12 @@ class GfmAutoComplete {
           } else if (command === MEMBER_COMMAND.UNASSIGN) {
             // Only include members which are assigned to Issuable currently
             return data.filter((member) => assignees.includes(member.search));
+          } else if (command === MEMBER_COMMAND.ASSIGN_REVIEWER) {
+            // Only include members which are not assigned as a reviewer to Issuable currently
+            return data.filter((member) => !reviewers.includes(member.search));
+          } else if (command === MEMBER_COMMAND.UNASSIGN_REVIEWER) {
+            // Only include members which are not assigned as a reviewer to Issuable currently
+            return data.filter((member) => reviewers.includes(member.search));
           }
 
           return data;
diff --git a/app/assets/javascripts/lib/graphql.js b/app/assets/javascripts/lib/graphql.js
index 1630f0d689c..cec689a44ca 100644
--- a/app/assets/javascripts/lib/graphql.js
+++ b/app/assets/javascripts/lib/graphql.js
@@ -4,6 +4,7 @@ import { ApolloLink } from 'apollo-link';
 import { BatchHttpLink } from 'apollo-link-batch-http';
 import { createHttpLink } from 'apollo-link-http';
 import { createUploadLink } from 'apollo-upload-client';
+import ActionCableLink from '~/actioncable_link';
 import { apolloCaptchaLink } from '~/captcha/apollo_captcha_link';
 import { StartupJSLink } from '~/lib/utils/apollo_startup_js_link';
 import csrf from '~/lib/utils/csrf';
@@ -83,15 +84,27 @@ export default (resolvers = {}, config = {}) => {
     });
   });
 
-  return new ApolloClient({
-    typeDefs,
-    link: ApolloLink.from([
+  const hasSubscriptionOperation = ({ query: { definitions } }) => {
+    return definitions.some(
+      ({ kind, operation }) => kind === 'OperationDefinition' && operation === 'subscription',
+    );
+  };
+
+  const appLink = ApolloLink.split(
+    hasSubscriptionOperation,
+    new ActionCableLink(),
+    ApolloLink.from([
       requestCounterLink,
       performanceBarLink,
       new StartupJSLink(),
       apolloCaptchaLink,
       uploadsLink,
     ]),
+  );
+
+  return new ApolloClient({
+    typeDefs,
+    link: appLink,
     cache: new InMemoryCache({
       ...cacheConfig,
       freezeResults: assumeImmutableResults,
diff --git a/app/assets/javascripts/pipeline_editor/components/ui/pipeline_editor_messages.vue b/app/assets/javascripts/pipeline_editor/components/ui/pipeline_editor_messages.vue
new file mode 100644
index 00000000000..091b202e10b
--- /dev/null
+++ b/app/assets/javascripts/pipeline_editor/components/ui/pipeline_editor_messages.vue
@@ -0,0 +1,155 @@
+<script>
+import { GlAlert } from '@gitlab/ui';
+import { getParameterValues, removeParams } from '~/lib/utils/url_utility';
+import { __, s__ } from '~/locale';
+import {
+  COMMIT_FAILURE,
+  COMMIT_SUCCESS,
+  DEFAULT_FAILURE,
+  DEFAULT_SUCCESS,
+  LOAD_FAILURE_UNKNOWN,
+} from '../../constants';
+import CodeSnippetAlert from '../code_snippet_alert/code_snippet_alert.vue';
+import {
+  CODE_SNIPPET_SOURCE_URL_PARAM,
+  CODE_SNIPPET_SOURCES,
+} from '../code_snippet_alert/constants';
+
+export default {
+  components: {
+    GlAlert,
+    CodeSnippetAlert,
+  },
+  errorTexts: {
+    [COMMIT_FAILURE]: s__('Pipelines|The GitLab CI configuration could not be updated.'),
+    [DEFAULT_FAILURE]: __('Something went wrong on our end.'),
+    [LOAD_FAILURE_UNKNOWN]: s__('Pipelines|The CI configuration was not loaded, please try again.'),
+  },
+  successTexts: {
+    [COMMIT_SUCCESS]: __('Your changes have been successfully committed.'),
+    [DEFAULT_SUCCESS]: __('Your action succeeded.'),
+  },
+  props: {
+    failureType: {
+      type: String,
+      required: false,
+      default: null,
+    },
+    failureReasons: {
+      type: Array,
+      required: false,
+      default: () => [],
+    },
+    showFailure: {
+      type: Boolean,
+      required: false,
+      default: false,
+    },
+    showSuccess: {
+      type: Boolean,
+      required: false,
+      default: false,
+    },
+    successType: {
+      type: String,
+      required: false,
+      default: null,
+    },
+  },
+  data() {
+    return {
+      codeSnippetCopiedFrom: '',
+    };
+  },
+  computed: {
+    failure() {
+      switch (this.failureType) {
+        case LOAD_FAILURE_UNKNOWN:
+          return {
+            text: this.$options.errorTexts[LOAD_FAILURE_UNKNOWN],
+            variant: 'danger',
+          };
+        case COMMIT_FAILURE:
+          return {
+            text: this.$options.errorTexts[COMMIT_FAILURE],
+            variant: 'danger',
+          };
+        default:
+          return {
+            text: this.$options.errorTexts[DEFAULT_FAILURE],
+            variant: 'danger',
+          };
+      }
+    },
+    success() {
+      switch (this.successType) {
+        case COMMIT_SUCCESS:
+          return {
+            text: this.$options.successTexts[COMMIT_SUCCESS],
+            variant: 'info',
+          };
+        default:
+          return {
+            text: this.$options.successTexts[DEFAULT_SUCCESS],
+            variant: 'info',
+          };
+      }
+    },
+  },
+  created() {
+    this.parseCodeSnippetSourceParam();
+  },
+  methods: {
+    dismissCodeSnippetAlert() {
+      this.codeSnippetCopiedFrom = '';
+    },
+    dismissFailure() {
+      this.$emit('hide-failure');
+    },
+    dismissSuccess() {
+      this.$emit('hide-success');
+    },
+    parseCodeSnippetSourceParam() {
+      const [codeSnippetCopiedFrom] = getParameterValues(CODE_SNIPPET_SOURCE_URL_PARAM);
+      if (codeSnippetCopiedFrom && CODE_SNIPPET_SOURCES.includes(codeSnippetCopiedFrom)) {
+        this.codeSnippetCopiedFrom = codeSnippetCopiedFrom;
+        window.history.replaceState(
+          {},
+          document.title,
+          removeParams([CODE_SNIPPET_SOURCE_URL_PARAM]),
+        );
+      }
+    },
+  },
+};
+</script>
+
+<template>
+  <div>
+    <code-snippet-alert
+      v-if="codeSnippetCopiedFrom"
+      :source="codeSnippetCopiedFrom"
+      class="gl-mb-5"
+      @dismiss="dismissCodeSnippetAlert"
+    />
+    <gl-alert
+      v-if="showSuccess"
+      :variant="success.variant"
+      class="gl-mb-5"
+      @dismiss="dismissSuccess"
+    >
+      {{ success.text }}
+    </gl-alert>
+    <gl-alert
+      v-if="showFailure"
+      :variant="failure.variant"
+      class="gl-mb-5"
+      @dismiss="dismissFailure"
+    >
+      {{ failure.text }}
+      <ul v-if="failureReasons.length" class="gl-mb-0">
+        <li v-for="reason in failureReasons" :key="reason">{{ reason }}</li>
+      </ul>
+    </gl-alert>
+  </div>
+</template>
diff --git a/app/assets/javascripts/pipeline_editor/constants.js b/app/assets/javascripts/pipeline_editor/constants.js
index 8d0ec6c3e2d..56862f17858 100644
--- a/app/assets/javascripts/pipeline_editor/constants.js
+++ b/app/assets/javascripts/pipeline_editor/constants.js
@@ -14,6 +14,7 @@ export const COMMIT_FAILURE = 'COMMIT_FAILURE';
 export const COMMIT_SUCCESS = 'COMMIT_SUCCESS';
 
 export const DEFAULT_FAILURE = 'DEFAULT_FAILURE';
+export const DEFAULT_SUCCESS = 'DEFAULT_SUCCESS';
 export const LOAD_FAILURE_UNKNOWN = 'LOAD_FAILURE_UNKNOWN';
 
 export const CREATE_TAB = 'CREATE_TAB';
diff --git a/app/assets/javascripts/pipeline_editor/pipeline_editor_app.vue b/app/assets/javascripts/pipeline_editor/pipeline_editor_app.vue
index 5f9662e90e6..bf36e00c662 100644
--- a/app/assets/javascripts/pipeline_editor/pipeline_editor_app.vue
+++ b/app/assets/javascripts/pipeline_editor/pipeline_editor_app.vue
@@ -1,22 +1,15 @@
 <script>
-import { GlAlert, GlLoadingIcon } from '@gitlab/ui';
+import { GlLoadingIcon } from '@gitlab/ui';
 import { fetchPolicies } from '~/lib/graphql';
 import httpStatusCodes from '~/lib/utils/http_status';
-import { getParameterValues, removeParams } from '~/lib/utils/url_utility';
-import { __, s__ } from '~/locale';
+import { s__ } from '~/locale';
 
 import { unwrapStagesWithNeeds } from '~/pipelines/components/unwrapping_utils';
-import CodeSnippetAlert from './components/code_snippet_alert/code_snippet_alert.vue';
-import {
-  CODE_SNIPPET_SOURCE_URL_PARAM,
-  CODE_SNIPPET_SOURCES,
-} from './components/code_snippet_alert/constants';
+
 import ConfirmUnsavedChangesDialog from './components/ui/confirm_unsaved_changes_dialog.vue';
 import PipelineEditorEmptyState from './components/ui/pipeline_editor_empty_state.vue';
+import PipelineEditorMessages from './components/ui/pipeline_editor_messages.vue';
 import {
-  COMMIT_FAILURE,
-  COMMIT_SUCCESS,
-  DEFAULT_FAILURE,
   EDITOR_APP_STATUS_EMPTY,
   EDITOR_APP_STATUS_ERROR,
   EDITOR_APP_STATUS_LOADING,
@@ -32,11 +25,10 @@ import PipelineEditorHome from './pipeline_editor_home.vue';
 export default {
   components: {
     ConfirmUnsavedChangesDialog,
-    GlAlert,
     GlLoadingIcon,
     PipelineEditorEmptyState,
     PipelineEditorHome,
-    CodeSnippetAlert,
+    PipelineEditorMessages,
   },
   inject: {
     ciConfigPath: {
@@ -51,15 +43,14 @@ export default {
       ciConfigData: {},
       failureType: null,
       failureReasons: [],
-      showStartScreen: false,
       initialCiFileContent: '',
       isNewCiConfigFile: false,
       lastCommittedContent: '',
       currentCiFileContent: '',
-      showFailureAlert: false,
-      showSuccessAlert: false,
       successType: null,
-      codeSnippetCopiedFrom: '',
+      showStartScreen: false,
+      showSuccess: false,
+      showFailure: false,
     };
   },
 
@@ -152,50 +143,12 @@ export default {
     isEmpty() {
       return this.currentCiFileContent === '';
     },
-    failure() {
-      switch (this.failureType) {
-        case LOAD_FAILURE_UNKNOWN:
-          return {
-            text: this.$options.errorTexts[LOAD_FAILURE_UNKNOWN],
-            variant: 'danger',
-          };
-        case COMMIT_FAILURE:
-          return {
-            text: this.$options.errorTexts[COMMIT_FAILURE],
-            variant: 'danger',
-          };
-        default:
-          return {
-            text: this.$options.errorTexts[DEFAULT_FAILURE],
-            variant: 'danger',
-          };
-      }
-    },
-    success() {
-      switch (this.successType) {
-        case COMMIT_SUCCESS:
-          return {
-            text: this.$options.successTexts[COMMIT_SUCCESS],
-            variant: 'info',
-          };
-        default:
-          return null;
-      }
-    },
   },
   i18n: {
     tabEdit: s__('Pipelines|Write pipeline configuration'),
     tabGraph: s__('Pipelines|Visualize'),
     tabLint: s__('Pipelines|Lint'),
   },
-  errorTexts: {
-    [COMMIT_FAILURE]: s__('Pipelines|The GitLab CI configuration could not be updated.'),
-    [DEFAULT_FAILURE]: __('Something went wrong on our end.'),
-    [LOAD_FAILURE_UNKNOWN]: s__('Pipelines|The CI configuration was not loaded, please try again.'),
-  },
-  successTexts: {
-    [COMMIT_SUCCESS]: __('Your changes have been successfully committed.'),
-  },
   watch: {
     isEmpty(flag) {
       if (flag) {
@@ -203,9 +156,6 @@ export default {
       }
     },
   },
-  created() {
-    this.parseCodeSnippetSourceParam();
-  },
   methods: {
     handleBlobContentError(error = {}) {
       const { networkError } = error;
@@ -223,12 +173,11 @@ export default {
         this.reportFailure(LOAD_FAILURE_UNKNOWN);
       }
     },
-
-    dismissFailure() {
-      this.showFailureAlert = false;
+    hideFailure() {
+      this.showFailure = false;
     },
-    dismissSuccess() {
-      this.showSuccessAlert = false;
+    hideSuccess() {
+      this.showSuccess = false;
     },
     async refetchContent() {
       this.$apollo.queries.initialCiFileContent.skip = false;
@@ -238,13 +187,13 @@ export default {
       this.setAppStatus(EDITOR_APP_STATUS_ERROR);
 
       window.scrollTo({ top: 0, behavior: 'smooth' });
-      this.showFailureAlert = true;
+      this.showFailure = true;
       this.failureType = type;
       this.failureReasons = reasons;
     },
     reportSuccess(type) {
       window.scrollTo({ top: 0, behavior: 'smooth' });
-      this.showSuccessAlert = true;
+      this.showSuccess = true;
       this.successType = type;
     },
     resetContent() {
@@ -277,20 +226,6 @@ export default {
       // if the user has made changes to the file that are unsaved.
       this.lastCommittedContent = this.currentCiFileContent;
     },
-    parseCodeSnippetSourceParam() {
-      const [codeSnippetCopiedFrom] = getParameterValues(CODE_SNIPPET_SOURCE_URL_PARAM);
-      if (codeSnippetCopiedFrom && CODE_SNIPPET_SOURCES.includes(codeSnippetCopiedFrom)) {
-        this.codeSnippetCopiedFrom = codeSnippetCopiedFrom;
-        window.history.replaceState(
-          {},
-          document.title,
-          removeParams([CODE_SNIPPET_SOURCE_URL_PARAM]),
-        );
-      }
-    },
-    dismissCodeSnippetAlert() {
-      this.codeSnippetCopiedFrom = '';
-    },
   },
 };
 </script>
@@ -303,31 +238,15 @@ export default {
       @createEmptyConfigFile="setNewEmptyCiConfigFile"
     />
     <div v-else>
-      <code-snippet-alert
-        v-if="codeSnippetCopiedFrom"
-        :source="codeSnippetCopiedFrom"
-        class="gl-mb-5"
-        @dismiss="dismissCodeSnippetAlert"
+      <pipeline-editor-messages
+        :failure-type="failureType"
+        :failure-reasons="failureReasons"
+        :show-failure="showFailure"
+        :show-success="showSuccess"
+        :success-type="successType"
+        @hide-success="hideSuccess"
+        @hide-failure="hideFailure"
       />
-      <gl-alert
-        v-if="showSuccessAlert"
-        :variant="success.variant"
-        class="gl-mb-5"
-        @dismiss="dismissSuccess"
-      >
-        {{ success.text }}
-      </gl-alert>
-      <gl-alert
-        v-if="showFailureAlert"
-        :variant="failure.variant"
-        class="gl-mb-5"
-        @dismiss="dismissFailure"
-      >
-        {{ failure.text }}
-        <ul v-if="failureReasons.length" class="gl-mb-0">
-          <li v-for="reason in failureReasons" :key="reason">{{ reason }}</li>
-        </ul>
-      </gl-alert>
       <pipeline-editor-home
         :ci-config-data="ciConfigData"
         :ci-file-content="currentCiFileContent"
diff --git a/app/assets/javascripts/sidebar/components/assignees/assignees_realtime.vue b/app/assets/javascripts/sidebar/components/assignees/assignees_realtime.vue
index f98798582c1..e7ef731eed8 100644
--- a/app/assets/javascripts/sidebar/components/assignees/assignees_realtime.vue
+++ b/app/assets/javascripts/sidebar/components/assignees/assignees_realtime.vue
@@ -1,6 +1,7 @@
 <script>
-import actionCable from '~/actioncable_consumer';
-import { getIdFromGraphQLId } from '~/graphql_shared/utils';
+import produce from 'immer';
+import { convertToGraphQLId, getIdFromGraphQLId } from '~/graphql_shared/utils';
+import { IssuableType } from '~/issue_show/constants';
 import { assigneesQueries } from '~/sidebar/constants';
 
 export default {
@@ -12,60 +13,62 @@ export default {
       required: false,
       default: null,
     },
-    issuableIid: {
+    issuableType: {
       type: String,
       required: true,
     },
-    projectPath: {
-      type: String,
+    issuableId: {
+      type: Number,
       required: true,
     },
-    issuableType: {
-      type: String,
+    queryVariables: {
+      type: Object,
       required: true,
     },
   },
+  computed: {
+    issuableClass() {
+      return Object.keys(IssuableType).find((key) => IssuableType[key] === this.issuableType);
+    },
+  },
   apollo: {
-    workspace: {
+    issuable: {
       query() {
         return assigneesQueries[this.issuableType].query;
       },
       variables() {
-        return {
-          iid: this.issuableIid,
-          fullPath: this.projectPath,
-        };
+        return this.queryVariables;
+      },
+      update(data) {
+        return data.workspace?.issuable;
       },
-      result(data) {
-        if (this.mediator) {
-          this.handleFetchResult(data);
-        }
+      subscribeToMore: {
+        document() {
+          return assigneesQueries[this.issuableType].subscription;
+        },
+        variables() {
+          return {
+            issuableId: convertToGraphQLId(this.issuableClass, this.issuableId),
+          };
+        },
+        updateQuery(prev, { subscriptionData }) {
+          if (prev && subscriptionData?.data?.issuableAssigneesUpdated) {
+            const data = produce(prev, (draftData) => {
+              draftData.workspace.issuable.assignees.nodes =
+                subscriptionData.data.issuableAssigneesUpdated.assignees.nodes;
+            });
+            if (this.mediator) {
+              this.handleFetchResult(data);
+            }
+            return data;
+          }
+          return prev;
+        },
       },
     },
   },
-  mounted() {
-    this.initActionCablePolling();
-  },
-  beforeDestroy() {
-    this.$options.subscription.unsubscribe();
-  },
   methods: {
-    received(data) {
-      if (data.event === 'updated') {
-        this.$apollo.queries.workspace.refetch();
-      }
-    },
-    initActionCablePolling() {
-      this.$options.subscription = actionCable.subscriptions.create(
-        {
-          channel: 'IssuesChannel',
-          project_path: this.projectPath,
-          iid: this.issuableIid,
-        },
-        { received: this.received },
-      );
-    },
-    handleFetchResult({ data }) {
+    handleFetchResult(data) {
       const { nodes } = data.workspace.issuable.assignees;
 
       const assignees = nodes.map((n) => ({
diff --git a/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees.vue b/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees.vue
index e15ea595190..ca95599742a 100644
--- a/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees.vue
+++ b/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees.vue
@@ -44,6 +44,10 @@ export default {
       type: String,
       required: true,
     },
+    issuableId: {
+      type: Number,
+      required: true,
+    },
     assigneeAvailabilityStatus: {
       type: Object,
       required: false,
@@ -61,6 +65,12 @@ export default {
       // Note: Realtime is only available on issues right now, future support for MR wil be built later.
       return this.glFeatures.realTimeIssueSidebar && this.issuableType === 'issue';
     },
+    queryVariables() {
+      return {
+        iid: this.issuableIid,
+        fullPath: this.projectPath,
+      };
+    },
     relativeUrlRoot() {
       return gon.relative_url_root ?? '';
     },
@@ -121,9 +131,9 @@ export default {
   <div>
     <assignees-realtime
       v-if="shouldEnableRealtime"
-      :issuable-iid="issuableIid"
-      :project-path="projectPath"
       :issuable-type="issuableType"
+      :issuable-id="issuableId"
+      :query-variables="queryVariables"
       :mediator="mediator"
     />
     <assignee-title
diff --git a/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees_widget.vue b/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees_widget.vue
index 78cac989850..2fc25151d1c 100644
--- a/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees_widget.vue
+++ b/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees_widget.vue
@@ -73,6 +73,11 @@ export default {
         return [IssuableType.Issue, IssuableType.MergeRequest].includes(value);
       },
     },
+    issuableId: {
+      type: Number,
+      required: false,
+      default: null,
+    },
     multipleAssignees: {
       type: Boolean,
       required: false,
@@ -340,9 +345,9 @@ export default {
   <div data-testid="assignees-widget">
     <sidebar-assignees-realtime
       v-if="shouldEnableRealtime"
-      :project-path="fullPath"
-      :issuable-iid="iid"
       :issuable-type="issuableType"
+      :issuable-id="issuableId"
+      :query-variables="queryVariables"
     />
     <sidebar-editable-item
       ref="toggle"
diff --git a/app/assets/javascripts/sidebar/constants.js b/app/assets/javascripts/sidebar/constants.js
index 80e07d556bf..58e4b0348ca 100644
--- a/app/assets/javascripts/sidebar/constants.js
+++ b/app/assets/javascripts/sidebar/constants.js
@@ -1,5 +1,6 @@
 import { IssuableType } from '~/issue_show/constants';
 import epicConfidentialQuery from '~/sidebar/queries/epic_confidential.query.graphql';
+import issuableAssigneesSubscription from '~/sidebar/queries/issuable_assignees.subscription.graphql';
 import issueConfidentialQuery from '~/sidebar/queries/issue_confidential.query.graphql';
 import issueDueDateQuery from '~/sidebar/queries/issue_due_date.query.graphql';
 import issueReferenceQuery from '~/sidebar/queries/issue_reference.query.graphql';
@@ -17,6 +18,7 @@ export const ASSIGNEES_DEBOUNCE_DELAY = 250;
 export const assigneesQueries = {
   [IssuableType.Issue]: {
     query: getIssueParticipants,
+    subscription: issuableAssigneesSubscription,
     mutation: updateAssigneesMutation,
   },
   [IssuableType.MergeRequest]: {
diff --git a/app/assets/javascripts/sidebar/mount_sidebar.js b/app/assets/javascripts/sidebar/mount_sidebar.js
index 1304e84814b..52a1efa04e4 100644
--- a/app/assets/javascripts/sidebar/mount_sidebar.js
+++ b/app/assets/javascripts/sidebar/mount_sidebar.js
@@ -53,7 +53,7 @@ function mountAssigneesComponentDeprecated(mediator) {
 
   if (!el) return;
 
-  const { iid, fullPath } = getSidebarOptions();
+  const { id, iid, fullPath } = getSidebarOptions();
   const assigneeAvailabilityStatus = getSidebarAssigneeAvailabilityData();
   // eslint-disable-next-line no-new
   new Vue({
@@ -74,6 +74,7 @@ function mountAssigneesComponentDeprecated(mediator) {
             isInIssuePage() || isInIncidentPage() || isInDesignPage()
               ? IssuableType.Issue
               : IssuableType.MergeRequest,
+          issuableId: id,
           assigneeAvailabilityStatus,
         },
       }),
@@ -85,7 +86,7 @@ function mountAssigneesComponent() {
 
   if (!el) return;
 
-  const { iid, fullPath, editable, projectMembersPath } = getSidebarOptions();
+  const { id, iid, fullPath, editable, projectMembersPath } = getSidebarOptions();
   // eslint-disable-next-line no-new
   new Vue({
     el,
@@ -108,6 +109,7 @@ function mountAssigneesComponent() {
             isInIssuePage() || isInIncidentPage() || isInDesignPage()
               ? IssuableType.Issue
               : IssuableType.MergeRequest,
+          issuableId: id,
           multipleAssignees: !el.dataset.maxAssignees,
         },
         scopedSlots: {
diff --git a/app/assets/javascripts/sidebar/queries/issuable_assignees.subscription.graphql b/app/assets/javascripts/sidebar/queries/issuable_assignees.subscription.graphql
new file mode 100644
index 00000000000..47ce094418c
--- /dev/null
+++ b/app/assets/javascripts/sidebar/queries/issuable_assignees.subscription.graphql
@@ -0,0 +1,16 @@
+#import "~/graphql_shared/fragments/user.fragment.graphql"
+
+subscription issuableAssigneesUpdated($issuableId: IssuableID!) {
+  issuableAssigneesUpdated(issuableId: $issuableId) {
+    ... on Issue {
+      assignees {
+        nodes {
+          ...User
+          status {
+            availability
+          }
+        }
+      }
+    }
+  }
+}