Merge branch '_acet-related-mrs-widget-rewrite' into 'master'

Rewrite related MRs widget with Vue

Closes #58926 and #57662

See merge request gitlab-org/gitlab-ce!27027

24 files changed, 651 insertions, 70 deletions

diff --git a/app/assets/javascripts/issue.js b/app/assets/javascripts/issue.js
index b3508f36cf9..cd1afb6ba83 100644
--- a/app/assets/javascripts/issue.js
+++ b/app/assets/javascripts/issue.js
@@ -15,7 +15,6 @@ export default class Issue {
     Issue.$btnNewBranch = $('#new-branch');
     Issue.createMrDropdownWrap = document.querySelector('.create-mr-dropdown-wrap');
 
-    Issue.initMergeRequests();
     if (document.querySelector('#related-branches')) {
       Issue.initRelatedBranches();
     }
@@ -143,19 +142,6 @@ export default class Issue {
     }
   }
 
-  static initMergeRequests() {
-    var $container;
-    $container = $('#merge-requests');
-    return axios
-      .get($container.data('url'))
-      .then(({ data }) => {
-        if ('html' in data) {
-          $container.html(data.html);
-        }
-      })
-      .catch(() => flash('Failed to load referenced merge requests'));
-  }
-
   static initRelatedBranches() {
     var $container;
     $container = $('#related-branches');
diff --git a/app/assets/javascripts/issue_show/index.js b/app/assets/javascripts/issue_show/index.js
index d08e8ba0c4b..529b6386221 100644
--- a/app/assets/javascripts/issue_show/index.js
+++ b/app/assets/javascripts/issue_show/index.js
@@ -1,12 +1,9 @@
 import Vue from 'vue';
-import sanitize from 'sanitize-html';
 import issuableApp from './components/app.vue';
+import { parseIssuableData } from './utils/parse_data';
 import '../vue_shared/vue_resource_interceptor';
 
 export default function initIssueableApp() {
-  const initialDataEl = document.getElementById('js-issuable-app-initial-data');
-  const props = JSON.parse(sanitize(initialDataEl.textContent).replace(/"/g, '"'));
-
   return new Vue({
     el: document.getElementById('js-issuable-app'),
     components: {
@@ -14,7 +11,7 @@ export default function initIssueableApp() {
     },
     render(createElement) {
       return createElement('issuable-app', {
-        props,
+        props: parseIssuableData(),
       });
     },
   });
diff --git a/app/assets/javascripts/issue_show/utils/parse_data.js b/app/assets/javascripts/issue_show/utils/parse_data.js
new file mode 100644
index 00000000000..05e384adad3
--- /dev/null
+++ b/app/assets/javascripts/issue_show/utils/parse_data.js
@@ -0,0 +1,15 @@
+import sanitize from 'sanitize-html';
+
+export const parseIssuableData = () => {
+  try {
+    const initialDataEl = document.getElementById('js-issuable-app-initial-data');
+
+    return JSON.parse(sanitize(initialDataEl.textContent).replace(/"/g, '"'));
+  } catch (e) {
+    console.error(e); // eslint-disable-line no-console
+
+    return {};
+  }
+};
+
+export default {};
diff --git a/app/assets/javascripts/pages/projects/issues/show.js b/app/assets/javascripts/pages/projects/issues/show.js
index 8987c8e3f47..0447d1f79fb 100644
--- a/app/assets/javascripts/pages/projects/issues/show.js
+++ b/app/assets/javascripts/pages/projects/issues/show.js
@@ -4,9 +4,11 @@ import ShortcutsIssuable from '~/behaviors/shortcuts/shortcuts_issuable';
 import ZenMode from '~/zen_mode';
 import '~/notes/index';
 import initIssueableApp from '~/issue_show';
+import initRelatedMergeRequestsApp from '~/related_merge_requests';
 
 export default function() {
   initIssueableApp();
+  initRelatedMergeRequestsApp();
   new Issue(); // eslint-disable-line no-new
   new ShortcutsIssuable(); // eslint-disable-line no-new
   new ZenMode(); // eslint-disable-line no-new
diff --git a/app/assets/javascripts/related_merge_requests/components/related_merge_requests.vue b/app/assets/javascripts/related_merge_requests/components/related_merge_requests.vue
new file mode 100644
index 00000000000..52d4b75a3a1
--- /dev/null
+++ b/app/assets/javascripts/related_merge_requests/components/related_merge_requests.vue
@@ -0,0 +1,121 @@
+<script>
+import { mapState, mapActions } from 'vuex';
+import { GlLoadingIcon } from '@gitlab/ui';
+import { sprintf, n__, s__ } from '~/locale';
+import Icon from '~/vue_shared/components/icon.vue';
+import RelatedIssuableItem from '~/vue_shared/components/issue/related_issuable_item.vue';
+import { parseIssuableData } from '../../issue_show/utils/parse_data';
+
+export default {
+  name: 'RelatedMergeRequests',
+  components: {
+    Icon,
+    GlLoadingIcon,
+    RelatedIssuableItem,
+  },
+  props: {
+    endpoint: {
+      type: String,
+      required: true,
+    },
+    projectNamespace: {
+      type: String,
+      required: true,
+    },
+    projectPath: {
+      type: String,
+      required: true,
+    },
+  },
+  computed: {
+    ...mapState(['isFetchingMergeRequests', 'mergeRequests', 'totalCount']),
+    closingMergeRequestsText() {
+      if (!this.hasClosingMergeRequest) {
+        return '';
+      }
+
+      const mrText = n__(
+        'When this merge request is accepted',
+        'When these merge requests are accepted',
+        this.totalCount,
+      );
+
+      return sprintf(s__('%{mrText}, this issue will be closed automatically.'), { mrText });
+    },
+  },
+  mounted() {
+    this.setInitialState({ apiEndpoint: this.endpoint });
+    this.fetchMergeRequests();
+  },
+  created() {
+    this.hasClosingMergeRequest = parseIssuableData().hasClosingMergeRequest;
+  },
+  methods: {
+    ...mapActions(['setInitialState', 'fetchMergeRequests']),
+    getAssignees(mr) {
+      if (mr.assignees) {
+        return mr.assignees;
+      }
+
+      return mr.assignee ? [mr.assignee] : [];
+    },
+  },
+};
+</script>
+
+<template>
+  <div v-if="isFetchingMergeRequests || (!isFetchingMergeRequests && totalCount)">
+    <div id="merge-requests" class="card-slim mt-3">
+      <div class="card-header">
+        <div class="card-title mt-0 mb-0 h5 merge-requests-title">
+          <span class="mr-1">
+            {{ __('Related merge requests') }}
+          </span>
+          <div v-if="totalCount" class="d-inline-flex lh-100 align-middle">
+            <div class="mr-count-badge">
+              <div class="mr-count-badge-count">
+                <svg class="s16 mr-1 text-secondary">
+                  <icon name="merge-request" class="mr-1 text-secondary" />
+                </svg>
+                <span class="js-items-count">{{ totalCount }}</span>
+              </div>
+            </div>
+          </div>
+        </div>
+      </div>
+      <div>
+        <div
+          v-if="isFetchingMergeRequests"
+          class="related-related-merge-requests-icon qa-related-merge-requests-loading-icon"
+        >
+          <gl-loading-icon label="Fetching related merge requests" class="py-2" />
+        </div>
+        <ul v-else class="content-list related-items-list">
+          <li v-for="mr in mergeRequests" :key="mr.id" class="list-item pt-0 pb-0">
+            <related-issuable-item
+              :id-key="mr.id"
+              :display-reference="mr.reference"
+              :title="mr.title"
+              :milestone="mr.milestone"
+              :assignees="getAssignees(mr)"
+              :created-at="mr.created_at"
+              :closed-at="mr.closed_at"
+              :merged-at="mr.merged_at"
+              :path="mr.web_url"
+              :state="mr.state"
+              :is-merge-request="true"
+              :pipeline-status="mr.head_pipeline && mr.head_pipeline.detailed_status"
+              path-id-separator="!"
+            />
+          </li>
+        </ul>
+      </div>
+    </div>
+    <div
+      v-if="hasClosingMergeRequest && !isFetchingMergeRequests"
+      class="issue-closed-by-widget second-block"
+    >
+      {{ closingMergeRequestsText }}
+    </div>
+  </div>
+</template>
diff --git a/app/assets/javascripts/related_merge_requests/index.js b/app/assets/javascripts/related_merge_requests/index.js
new file mode 100644
index 00000000000..092ff1df00f
--- /dev/null
+++ b/app/assets/javascripts/related_merge_requests/index.js
@@ -0,0 +1,24 @@
+import Vue from 'vue';
+import RelatedMergeRequests from './components/related_merge_requests.vue';
+import createStore from './store';
+
+export default function initRelatedMergeRequests() {
+  const relatedMergeRequestsElement = document.querySelector('#js-related-merge-requests');
+
+  if (relatedMergeRequestsElement) {
+    const { endpoint, projectPath, projectNamespace } = relatedMergeRequestsElement.dataset;
+
+    // eslint-disable-next-line no-new
+    new Vue({
+      el: relatedMergeRequestsElement,
+      components: {
+        RelatedMergeRequests,
+      },
+      store: createStore(),
+      render: createElement =>
+        createElement('related-merge-requests', {
+          props: { endpoint, projectNamespace, projectPath },
+        }),
+    });
+  }
+}
diff --git a/app/assets/javascripts/related_merge_requests/store/actions.js b/app/assets/javascripts/related_merge_requests/store/actions.js
new file mode 100644
index 00000000000..69abeaaf7db
--- /dev/null
+++ b/app/assets/javascripts/related_merge_requests/store/actions.js
@@ -0,0 +1,37 @@
+import axios from '~/lib/utils/axios_utils';
+import createFlash from '~/flash';
+import { s__ } from '~/locale';
+import { normalizeHeaders } from '~/lib/utils/common_utils';
+import * as types from './mutation_types';
+
+const REQUEST_PAGE_COUNT = 100;
+
+export const setInitialState = ({ commit }, props) => {
+  commit(types.SET_INITIAL_STATE, props);
+};
+
+export const requestData = ({ commit }) => commit(types.REQUEST_DATA);
+
+export const receiveDataSuccess = ({ commit }, data) => commit(types.RECEIVE_DATA_SUCCESS, data);
+
+export const receiveDataError = ({ commit }) => commit(types.RECEIVE_DATA_ERROR);
+
+export const fetchMergeRequests = ({ state, dispatch }) => {
+  dispatch('requestData');
+
+  return axios
+    .get(`${state.apiEndpoint}?per_page=${REQUEST_PAGE_COUNT}`)
+    .then(res => {
+      const { headers, data } = res;
+      const total = Number(normalizeHeaders(headers)['X-TOTAL']) || 0;
+
+      dispatch('receiveDataSuccess', { data, total });
+    })
+    .catch(() => {
+      dispatch('receiveDataError');
+      createFlash(s__('Something went wrong while fetching related merge requests.'));
+    });
+};
+
+// prevent babel-plugin-rewire from generating an invalid default during karma tests
+export default () => {};
diff --git a/app/assets/javascripts/related_merge_requests/store/index.js b/app/assets/javascripts/related_merge_requests/store/index.js
new file mode 100644
index 00000000000..dcb70c22bcb
--- /dev/null
+++ b/app/assets/javascripts/related_merge_requests/store/index.js
@@ -0,0 +1,14 @@
+import Vue from 'vue';
+import Vuex from 'vuex';
+import createState from './state';
+import * as actions from './actions';
+import mutations from './mutations';
+
+Vue.use(Vuex);
+
+export default () =>
+  new Vuex.Store({
+    state: createState(),
+    actions,
+    mutations,
+  });
diff --git a/app/assets/javascripts/related_merge_requests/store/mutation_types.js b/app/assets/javascripts/related_merge_requests/store/mutation_types.js
new file mode 100644
index 00000000000..31d4fe032e1
--- /dev/null
+++ b/app/assets/javascripts/related_merge_requests/store/mutation_types.js
@@ -0,0 +1,4 @@
+export const SET_INITIAL_STATE = 'SET_INITIAL_STATE';
+export const REQUEST_DATA = 'REQUEST_DATA';
+export const RECEIVE_DATA_SUCCESS = 'RECEIVE_DATA_SUCCESS';
+export const RECEIVE_DATA_ERROR = 'RECEIVE_DATA_ERROR';
diff --git a/app/assets/javascripts/related_merge_requests/store/mutations.js b/app/assets/javascripts/related_merge_requests/store/mutations.js
new file mode 100644
index 00000000000..11ca28a5fb9
--- /dev/null
+++ b/app/assets/javascripts/related_merge_requests/store/mutations.js
@@ -0,0 +1,19 @@
+import * as types from './mutation_types';
+
+export default {
+  [types.SET_INITIAL_STATE](state, { apiEndpoint }) {
+    state.apiEndpoint = apiEndpoint;
+  },
+  [types.REQUEST_DATA](state) {
+    state.isFetchingMergeRequests = true;
+  },
+  [types.RECEIVE_DATA_SUCCESS](state, { data, total }) {
+    state.isFetchingMergeRequests = false;
+    state.mergeRequests = data;
+    state.totalCount = total;
+  },
+  [types.RECEIVE_DATA_ERROR](state) {
+    state.isFetchingMergeRequests = false;
+    state.hasErrorFetchingMergeRequests = true;
+  },
+};
diff --git a/app/assets/javascripts/related_merge_requests/store/state.js b/app/assets/javascripts/related_merge_requests/store/state.js
new file mode 100644
index 00000000000..bc3468a025b
--- /dev/null
+++ b/app/assets/javascripts/related_merge_requests/store/state.js
@@ -0,0 +1,7 @@
+export default () => ({
+  apiEndpoint: '',
+  isFetchingMergeRequests: false,
+  hasErrorFetchingMergeRequests: false,
+  mergeRequests: [],
+  totalCount: 0,
+});
diff --git a/app/assets/javascripts/vue_shared/components/issue/related_issuable_item.vue b/app/assets/javascripts/vue_shared/components/issue/related_issuable_item.vue
index 27cfa8abb24..d4d18614f93 100644
--- a/app/assets/javascripts/vue_shared/components/issue/related_issuable_item.vue
+++ b/app/assets/javascripts/vue_shared/components/issue/related_issuable_item.vue
@@ -1,15 +1,17 @@
 <script>
 import { GlTooltipDirective } from '@gitlab/ui';
-import { __, sprintf } from '~/locale';
-import IssueMilestone from '~/vue_shared/components/issue/issue_milestone.vue';
-import IssueAssignees from '~/vue_shared/components/issue/issue_assignees.vue';
-import relatedIssuableMixin from '~/vue_shared/mixins/related_issuable_mixin';
+import { sprintf } from '~/locale';
+import IssueMilestone from '../../components/issue/issue_milestone.vue';
+import IssueAssignees from '../../components/issue/issue_assignees.vue';
+import relatedIssuableMixin from '../../mixins/related_issuable_mixin';
+import CiIcon from '../ci_icon.vue';
 
 export default {
   name: 'IssueItem',
   components: {
     IssueMilestone,
     IssueAssignees,
+    CiIcon,
   },
   directives: {
     GlTooltip: GlTooltipDirective,
@@ -27,9 +29,9 @@ export default {
       return sprintf(
         '<span class="bold">%{state}</span> %{timeInWords}<br/><span class="text-tertiary">%{timestamp}</span>',
         {
-          state: this.isOpen ? __('Opened') : __('Closed'),
-          timeInWords: this.isOpen ? this.createdAtInWords : this.closedAtInWords,
-          timestamp: this.isOpen ? this.createdAtTimestamp : this.closedAtTimestamp,
+          state: this.stateText,
+          timeInWords: this.stateTimeInWords,
+          timestamp: this.stateTimestamp,
         },
       );
     },
@@ -84,6 +86,11 @@ export default {
           {{ pathIdSeparator }}{{ itemId }}
         </div>
         <div class="item-meta-child d-flex align-items-center">
+          <span v-if="hasPipeline" class="mr-ci-status pr-2">
+            <a :href="pipelineStatus.details_path">
+              <ci-icon v-gl-tooltip :status="pipelineStatus" :title="pipelineStatusTooltip" />
+            </a>
+          </span>
           <issue-milestone
             v-if="hasMilestone"
             :milestone="milestone"
diff --git a/app/assets/javascripts/vue_shared/mixins/related_issuable_mixin.js b/app/assets/javascripts/vue_shared/mixins/related_issuable_mixin.js
index 455ae832234..8e0e4baa75a 100644
--- a/app/assets/javascripts/vue_shared/mixins/related_issuable_mixin.js
+++ b/app/assets/javascripts/vue_shared/mixins/related_issuable_mixin.js
@@ -1,4 +1,5 @@
 import _ from 'underscore';
+import { sprintf, __ } from '~/locale';
 import { formatDate } from '~/lib/utils/datetime_utility';
 import tooltip from '~/vue_shared/directives/tooltip';
 import icon from '~/vue_shared/components/icon.vue';
@@ -58,6 +59,11 @@ const mixins = {
       required: false,
       default: '',
     },
+    mergedAt: {
+      type: String,
+      required: false,
+      default: '',
+    },
     milestone: {
       type: Object,
       required: false,
@@ -83,6 +89,16 @@ const mixins = {
       required: false,
       default: false,
     },
+    isMergeRequest: {
+      type: Boolean,
+      required: false,
+      default: false,
+    },
+    pipelineStatus: {
+      type: Object,
+      required: false,
+      default: () => ({}),
+    },
   },
   components: {
     icon,
@@ -95,12 +111,18 @@ const mixins = {
     hasState() {
       return this.state && this.state.length > 0;
     },
+    hasPipeline() {
+      return this.isMergeRequest && this.pipelineStatus && Object.keys(this.pipelineStatus).length;
+    },
     isOpen() {
       return this.state === 'opened';
     },
     isClosed() {
       return this.state === 'closed';
     },
+    isMerged() {
+      return this.state === 'merged';
+    },
     hasTitle() {
       return this.title.length > 0;
     },
@@ -108,9 +130,17 @@ const mixins = {
       return !_.isEmpty(this.milestone);
     },
     iconName() {
+      if (this.isMergeRequest && this.isMerged) {
+        return 'merge';
+      }
+
       return this.isOpen ? 'issue-open-m' : 'issue-close';
     },
     iconClass() {
+      if (this.isMergeRequest && this.isClosed) {
+        return 'merge-request-status closed issue-token-state-icon-closed';
+      }
+
       return this.isOpen ? 'issue-token-state-icon-open' : 'issue-token-state-icon-closed';
     },
     computedLinkElementType() {
@@ -131,12 +161,44 @@ const mixins = {
     createdAtTimestamp() {
       return this.createdAt ? formatDate(new Date(this.createdAt)) : '';
     },
+    mergedAtTimestamp() {
+      return this.mergedAt ? formatDate(new Date(this.mergedAt)) : '';
+    },
+    mergedAtInWords() {
+      return this.mergedAt ? this.timeFormated(this.mergedAt) : '';
+    },
     closedAtInWords() {
       return this.closedAt ? this.timeFormated(this.closedAt) : '';
     },
     closedAtTimestamp() {
       return this.closedAt ? formatDate(new Date(this.closedAt)) : '';
     },
+    stateText() {
+      if (this.isMerged) {
+        return __('Merged');
+      }
+
+      return this.isOpen ? __('Opened') : __('Closed');
+    },
+    stateTimeInWords() {
+      if (this.isMerged) {
+        return this.mergedAtInWords;
+      }
+
+      return this.isOpen ? this.createdAtInWords : this.closedAtInWords;
+    },
+    stateTimestamp() {
+      if (this.isMerged) {
+        return this.mergedAtTimestamp;
+      }
+
+      return this.isOpen ? this.createdAtTimestamp : this.closedAtTimestamp;
+    },
+    pipelineStatusTooltip() {
+      return this.hasPipeline
+        ? sprintf(__('Pipeline: %{status}'), { status: this.pipelineStatus.label })
+        : '';
+    },
   },
   methods: {
     onRemoveRequest() {
diff --git a/app/helpers/issuables_helper.rb b/app/helpers/issuables_helper.rb
index 0622cdfc196..52c49498e9b 100644
--- a/app/helpers/issuables_helper.rb
+++ b/app/helpers/issuables_helper.rb
@@ -277,6 +277,8 @@ module IssuablesHelper
       initialTaskStatus: issuable.task_status
     }
 
+    data[:hasClosingMergeRequest] = issuable.merge_requests_count != 0 if issuable.is_a?(Issue)
+
     if parent.is_a?(Group)
       data[:groupPath] = parent.path
     else
diff --git a/app/views/projects/issues/_closed_by_box.html.haml b/app/views/projects/issues/_closed_by_box.html.haml
deleted file mode 100644
index 38469ed4774..00000000000
--- a/app/views/projects/issues/_closed_by_box.html.haml
+++ /dev/null
@@ -1,4 +0,0 @@
-.issue-closed-by-widget.second-block
-  - pluralized_mr_this = merge_request_count > 1 ? "these" : "this"
-  - pluralized_mr_is = merge_request_count > 1 ? "are" : "is"
-  When #{pluralized_mr_this} merge #{"request".pluralize(merge_request_count)} #{pluralized_mr_is} accepted, this issue will be closed automatically.
diff --git a/app/views/projects/issues/_merge_requests.html.haml b/app/views/projects/issues/_merge_requests.html.haml
deleted file mode 100644
index 6a66c2e57cc..00000000000
--- a/app/views/projects/issues/_merge_requests.html.haml
+++ /dev/null
@@ -1,36 +0,0 @@
-- if @merge_requests.any?
-  .card-slim.mt-3
-    .card-header
-      %h2.card-title.mt-0.mb-0.h5.merge-requests-title
-        %span.mr-1.bold
-          = _('Related merge requests')
-        .d-inline-flex.lh-100.align-middle
-          .mr-count-badge
-            .mr-count-badge-count
-              = sprite_icon('merge-request', size: 16, css_class: 'mr-1 text-secondary')
-              = @merge_requests.count
-    %ul.content-list.related-items-list
-      - has_any_head_pipeline = @merge_requests.any?(&:head_pipeline_id)
-      - @merge_requests.each do |merge_request|
-        - merge_request = merge_request.present(current_user: current_user)
-        %li.list-item.py-0.px-0
-          .item-body.issuable-info-container.py-lg-3.px-lg-3.pl-md-3
-            .item-contents
-              .item-title.d-flex.align-items-center.mr-title
-                = render partial: 'projects/issues/merge_requests_status', locals: { merge_request: merge_request, css_class: 'd-none d-xl-block append-right-8' }
-                = link_to merge_request.title, merge_request_path(merge_request), { class: 'mr-title-link'}
-              .item-meta
-                = render partial: 'projects/issues/merge_requests_status', locals: { merge_request: merge_request, css_class: 'd-xl-none d-lg-block append-right-5' }
-                %span.d-flex.align-items-center.append-right-8.mr-item-path.item-path-id.mt-0
-                  %span.path-id-text.bold.text-truncate{ data: { toggle: 'tooltip'}, title: merge_request.target_project.full_path }
-                    = merge_request.target_project.full_path
-                  = merge_request.to_reference
-                %span.mr-ci-status.flex-md-grow-1.justify-content-end.d-flex.ml-md-2
-                  - if merge_request.can_read_pipeline?
-                    = render 'ci/status/icon', status: merge_request.head_pipeline.detailed_status(current_user), tooltip_placement: 'bottom'
-                  - elsif has_any_head_pipeline
-                    = icon('blank fw')
-
-  - if @closed_by_merge_requests.present?
-    %p
-      = render partial: 'projects/issues/closed_by_box', locals: {merge_request_count: @merge_requests.count}
diff --git a/app/views/projects/issues/show.html.haml b/app/views/projects/issues/show.html.haml
index f8969fbb5a2..2c95ac6dbb3 100644
--- a/app/views/projects/issues/show.html.haml
+++ b/app/views/projects/issues/show.html.haml
@@ -77,12 +77,11 @@
 
       = edited_time_ago_with_tooltip(@issue, placement: 'bottom', html_class: 'issue-edited-ago js-issue-edited-ago')
 
-    #merge-requests{ data: { url: referenced_merge_requests_project_issue_path(@project, @issue) } }
-      // This element is filled in using JavaScript.
+    #js-related-merge-requests{ data: { endpoint: api_v4_projects_issues_related_merge_requests_path(id: @project.id, issue_iid: @issue.iid), project_namespace: @project.namespace.path, project_path: @project.path } }
 
     - if can?(current_user, :download_code, @project)
       #related-branches{ data: { url: related_branches_project_issue_path(@project, @issue) } }
-        // This element is filled in using JavaScript.
+        -# This element is filled in using JavaScript.
 
   .content-block.emoji-block.emoji-block-sticky
     .row
diff --git a/changelogs/unreleased/_acet-related-mrs-widget-rewrite.yml b/changelogs/unreleased/_acet-related-mrs-widget-rewrite.yml
new file mode 100644
index 00000000000..b773eb2720c
--- /dev/null
+++ b/changelogs/unreleased/_acet-related-mrs-widget-rewrite.yml
@@ -0,0 +1,5 @@
+---
+title: Rewrite related MRs widget with Vue
+merge_request: 27027
+author:
+type: other
diff --git a/locale/gitlab.pot b/locale/gitlab.pot
index 711baff9f9a..3bc48e8c5d2 100644
--- a/locale/gitlab.pot
+++ b/locale/gitlab.pot
@@ -141,6 +141,9 @@ msgstr ""
 msgid "%{lock_path} is locked by GitLab User %{lock_user_id}"
 msgstr ""
 
+msgid "%{mrText}, this issue will be closed automatically."
+msgstr ""
+
 msgid "%{number_commits_behind} commits behind %{default_branch}, %{number_commits_ahead} commits ahead"
 msgstr ""
 
@@ -5830,6 +5833,9 @@ msgstr ""
 msgid "Pipeline triggers"
 msgstr ""
 
+msgid "Pipeline: %{status}"
+msgstr ""
+
 msgid "PipelineCharts|Failed:"
 msgstr ""
 
@@ -7510,6 +7516,9 @@ msgstr ""
 msgid "Something went wrong while fetching comments. Please try again."
 msgstr ""
 
+msgid "Something went wrong while fetching related merge requests."
+msgstr ""
+
 msgid "Something went wrong while fetching the environments for this merge request. Please try again."
 msgstr ""
 
@@ -9238,6 +9247,11 @@ msgstr ""
 msgid "When enabled, users cannot use GitLab until the terms have been accepted."
 msgstr ""
 
+msgid "When this merge request is accepted"
+msgid_plural "When these merge requests are accepted"
+msgstr[0] ""
+msgstr[1] ""
+
 msgid "When:"
 msgstr ""
 
diff --git a/spec/features/issuables/markdown_references/internal_references_spec.rb b/spec/features/issuables/markdown_references/internal_references_spec.rb
index 23385ba65fc..870e92b8de8 100644
--- a/spec/features/issuables/markdown_references/internal_references_spec.rb
+++ b/spec/features/issuables/markdown_references/internal_references_spec.rb
@@ -70,7 +70,7 @@ describe "Internal references", :js do
 
             page.within("#merge-requests ul") do
               expect(page).to have_content(private_project_merge_request.title)
-              expect(page).to have_css(".merge-request-status")
+              expect(page).to have_css(".ic-issue-open-m")
             end
 
             expect(page).to have_content("mentioned in merge request #{private_project_merge_request.to_reference(public_project)}")
diff --git a/spec/javascripts/fixtures/issues.rb b/spec/javascripts/fixtures/issues.rb
index 645b3aa788a..0f3f9a10f94 100644
--- a/spec/javascripts/fixtures/issues.rb
+++ b/spec/javascripts/fixtures/issues.rb
@@ -65,3 +65,61 @@ describe Projects::IssuesController, '(JavaScript fixtures)', type: :controller
     store_frontend_fixture(response, fixture_file_name)
   end
 end
+
+describe API::Issues, '(JavaScript fixtures)', type: :request do
+  include ApiHelpers
+  include JavaScriptFixturesHelpers
+
+  def get_related_merge_requests(project_id, issue_iid, user = nil)
+    get api("/projects/#{project_id}/issues/#{issue_iid}/related_merge_requests", user)
+  end
+
+  def create_referencing_mr(user, project, issue)
+    attributes = {
+      author: user,
+      source_project: project,
+      target_project: project,
+      source_branch: "master",
+      target_branch: "test",
+      assignee: user,
+      description: "See #{issue.to_reference}"
+    }
+    create(:merge_request, attributes).tap do |merge_request|
+      create(:note, :system, project: issue.project, noteable: issue, author: user, note: merge_request.to_reference(full: true))
+    end
+  end
+
+  it 'issues/related_merge_requests.json' do |example|
+    user = create(:user)
+    project = create(:project, :public, creator_id: user.id, namespace: user.namespace)
+    issue_title = 'foo'
+    issue_description = 'closed'
+    milestone = create(:milestone, title: '1.0.0', project: project)
+    issue = create :issue,
+            author: user,
+            assignees: [user],
+            project: project,
+            milestone: milestone,
+            created_at: generate(:past_time),
+            updated_at: 1.hour.ago,
+            title: issue_title,
+            description: issue_description
+
+    project.add_reporter(user)
+    create_referencing_mr(user, project, issue)
+
+    create(:merge_request,
+           :simple,
+           author: user,
+           source_project: project,
+           target_project: project,
+           description: "Some description")
+    project2 = create(:project, :public, creator_id: user.id, namespace: user.namespace)
+    create_referencing_mr(user, project2, issue).update!(head_pipeline: create(:ci_pipeline))
+
+    get_related_merge_requests(project.id, issue.iid, user)
+
+    expect(response).to be_success
+    store_frontend_fixture(response, example.description)
+  end
+end
diff --git a/spec/javascripts/related_merge_requests/components/related_merge_requests_spec.js b/spec/javascripts/related_merge_requests/components/related_merge_requests_spec.js
new file mode 100644
index 00000000000..29760f79c3c
--- /dev/null
+++ b/spec/javascripts/related_merge_requests/components/related_merge_requests_spec.js
@@ -0,0 +1,89 @@
+import { mount, createLocalVue } from '@vue/test-utils';
+import MockAdapter from 'axios-mock-adapter';
+import axios from '~/lib/utils/axios_utils';
+import RelatedIssuableItem from '~/vue_shared/components/issue/related_issuable_item.vue';
+import RelatedMergeRequests from '~/related_merge_requests/components/related_merge_requests.vue';
+import createStore from '~/related_merge_requests/store/index';
+
+const FIXTURE_PATH = 'issues/related_merge_requests.json';
+const API_ENDPOINT = '/api/v4/projects/2/issues/33/related_merge_requests';
+const localVue = createLocalVue();
+
+describe('RelatedMergeRequests', () => {
+  let wrapper;
+  let mock;
+  let mockData;
+
+  beforeEach(done => {
+    loadFixtures(FIXTURE_PATH);
+    mockData = getJSONFixture(FIXTURE_PATH);
+    mock = new MockAdapter(axios);
+    mock.onGet(`${API_ENDPOINT}?per_page=100`).reply(200, mockData, { 'x-total': 2 });
+
+    wrapper = mount(RelatedMergeRequests, {
+      localVue,
+      sync: false,
+      store: createStore(),
+      propsData: {
+        endpoint: API_ENDPOINT,
+        projectNamespace: 'gitlab-org',
+        projectPath: 'gitlab-ce',
+      },
+    });
+
+    setTimeout(done);
+  });
+
+  afterEach(() => {
+    wrapper.destroy();
+    mock.restore();
+  });
+
+  describe('methods', () => {
+    describe('getAssignees', () => {
+      const assignees = [{ name: 'foo' }, { name: 'bar' }];
+
+      describe('when there is assignees array', () => {
+        it('should return assignees array', () => {
+          const mr = { assignees };
+
+          expect(wrapper.vm.getAssignees(mr)).toEqual(assignees);
+        });
+      });
+
+      it('should return an array with single assingee', () => {
+        const mr = { assignee: assignees[0] };
+
+        expect(wrapper.vm.getAssignees(mr)).toEqual([assignees[0]]);
+      });
+
+      it('should return empty array when assignee is not set', () => {
+        expect(wrapper.vm.getAssignees({})).toEqual([]);
+        expect(wrapper.vm.getAssignees({ assignee: null })).toEqual([]);
+      });
+    });
+  });
+
+  describe('template', () => {
+    it('should render related merge request items', () => {
+      expect(wrapper.find('.js-items-count').text()).toEqual('2');
+      expect(wrapper.findAll(RelatedIssuableItem).length).toEqual(2);
+
+      const props = wrapper
+        .findAll(RelatedIssuableItem)
+        .at(1)
+        .props();
+      const data = mockData[1];
+
+      expect(props.idKey).toEqual(data.id);
+      expect(props.pathIdSeparator).toEqual('!');
+      expect(props.pipelineStatus).toBe(data.head_pipeline.detailed_status);
+      expect(props.assignees).toEqual([data.assignee]);
+      expect(props.isMergeRequest).toBe(true);
+      expect(props.confidential).toEqual(false);
+      expect(props.title).toEqual(data.title);
+      expect(props.state).toEqual(data.state);
+      expect(props.createdAt).toEqual(data.created_at);
+    });
+  });
+});
diff --git a/spec/javascripts/related_merge_requests/store/actions_spec.js b/spec/javascripts/related_merge_requests/store/actions_spec.js
new file mode 100644
index 00000000000..65e436fbb17
--- /dev/null
+++ b/spec/javascripts/related_merge_requests/store/actions_spec.js
@@ -0,0 +1,110 @@
+import MockAdapter from 'axios-mock-adapter';
+import axios from '~/lib/utils/axios_utils';
+import * as types from '~/related_merge_requests/store/mutation_types';
+import actionsModule, * as actions from '~/related_merge_requests/store/actions';
+import testAction from 'spec/helpers/vuex_action_helper';
+
+describe('RelatedMergeRequest store actions', () => {
+  let state;
+  let flashSpy;
+  let mock;
+
+  beforeEach(() => {
+    state = {
+      apiEndpoint: '/api/related_merge_requests',
+    };
+    flashSpy = spyOnDependency(actionsModule, 'createFlash');
+    mock = new MockAdapter(axios);
+  });
+
+  afterEach(() => {
+    mock.restore();
+  });
+
+  describe('setInitialState', () => {
+    it('commits types.SET_INITIAL_STATE with given props', done => {
+      const props = { a: 1, b: 2 };
+
+      testAction(
+        actions.setInitialState,
+        props,
+        {},
+        [{ type: types.SET_INITIAL_STATE, payload: props }],
+        [],
+        done,
+      );
+    });
+  });
+
+  describe('requestData', () => {
+    it('commits types.REQUEST_DATA', done => {
+      testAction(actions.requestData, null, {}, [{ type: types.REQUEST_DATA }], [], done);
+    });
+  });
+
+  describe('receiveDataSuccess', () => {
+    it('commits types.RECEIVE_DATA_SUCCESS with data', done => {
+      const data = { a: 1, b: 2 };
+
+      testAction(
+        actions.receiveDataSuccess,
+        data,
+        {},
+        [{ type: types.RECEIVE_DATA_SUCCESS, payload: data }],
+        [],
+        done,
+      );
+    });
+  });
+
+  describe('receiveDataError', () => {
+    it('commits types.RECEIVE_DATA_ERROR', done => {
+      testAction(
+        actions.receiveDataError,
+        null,
+        {},
+        [{ type: types.RECEIVE_DATA_ERROR }],
+        [],
+        done,
+      );
+    });
+  });
+
+  describe('fetchMergeRequests', () => {
+    describe('for a successful request', () => {
+      it('should dispatch success action', done => {
+        const data = { a: 1 };
+        mock.onGet(`${state.apiEndpoint}?per_page=100`).replyOnce(200, data, { 'x-total': 2 });
+
+        testAction(
+          actions.fetchMergeRequests,
+          null,
+          state,
+          [],
+          [{ type: 'requestData' }, { type: 'receiveDataSuccess', payload: { data, total: 2 } }],
+          done,
+        );
+      });
+    });
+
+    describe('for a failing request', () => {
+      it('should dispatch error action', done => {
+        mock.onGet(`${state.apiEndpoint}?per_page=100`).replyOnce(400);
+
+        testAction(
+          actions.fetchMergeRequests,
+          null,
+          state,
+          [],
+          [{ type: 'requestData' }, { type: 'receiveDataError' }],
+          () => {
+            expect(flashSpy).toHaveBeenCalledTimes(1);
+            expect(flashSpy).toHaveBeenCalledWith(jasmine.stringMatching('Something went wrong'));
+
+            done();
+          },
+        );
+      });
+    });
+  });
+});
diff --git a/spec/javascripts/related_merge_requests/store/mutations_spec.js b/spec/javascripts/related_merge_requests/store/mutations_spec.js
new file mode 100644
index 00000000000..21b6e26376b
--- /dev/null
+++ b/spec/javascripts/related_merge_requests/store/mutations_spec.js
@@ -0,0 +1,49 @@
+import mutations from '~/related_merge_requests/store/mutations';
+import * as types from '~/related_merge_requests/store/mutation_types';
+
+describe('RelatedMergeRequests Store Mutations', () => {
+  describe('SET_INITIAL_STATE', () => {
+    it('should set initial state according to given data', () => {
+      const apiEndpoint = '/api';
+      const state = {};
+
+      mutations[types.SET_INITIAL_STATE](state, { apiEndpoint });
+
+      expect(state.apiEndpoint).toEqual(apiEndpoint);
+    });
+  });
+
+  describe('REQUEST_DATA', () => {
+    it('should set loading flag', () => {
+      const state = {};
+
+      mutations[types.REQUEST_DATA](state);
+
+      expect(state.isFetchingMergeRequests).toEqual(true);
+    });
+  });
+
+  describe('RECEIVE_DATA_SUCCESS', () => {
+    it('should set loading flag and data', () => {
+      const state = {};
+      const mrs = [1, 2, 3];
+
+      mutations[types.RECEIVE_DATA_SUCCESS](state, { data: mrs, total: mrs.length });
+
+      expect(state.isFetchingMergeRequests).toEqual(false);
+      expect(state.mergeRequests).toEqual(mrs);
+      expect(state.totalCount).toEqual(mrs.length);
+    });
+  });
+
+  describe('RECEIVE_DATA_ERROR', () => {
+    it('should set loading and error flags', () => {
+      const state = {};
+
+      mutations[types.RECEIVE_DATA_ERROR](state);
+
+      expect(state.isFetchingMergeRequests).toEqual(false);
+      expect(state.hasErrorFetchingMergeRequests).toEqual(true);
+    });
+  });
+});