Add merge request popover with details

- Show pipeline status, title, MR Status and project path
- Popover attached to gitlab flavored markdown everywhere, including:
  + MR/Issue Title
  + MR/Issue description
  + MR/Issue comments
  + Rendered markdown files

18 files changed, 438 insertions, 13 deletions

diff --git a/app/assets/javascripts/behaviors/markdown/render_gfm.js b/app/assets/javascripts/behaviors/markdown/render_gfm.js
index fc9286d15e6..bfb073fdcdc 100644
--- a/app/assets/javascripts/behaviors/markdown/render_gfm.js
+++ b/app/assets/javascripts/behaviors/markdown/render_gfm.js
@@ -4,6 +4,7 @@ import renderMath from './render_math';
 import renderMermaid from './render_mermaid';
 import highlightCurrentUser from './highlight_current_user';
 import initUserPopovers from '../../user_popovers';
+import initMRPopovers from '../../mr_popover';
 
 // Render GitLab flavoured Markdown
 //
@@ -15,6 +16,7 @@ $.fn.renderGFM = function renderGFM() {
   renderMermaid(this.find('.js-render-mermaid'));
   highlightCurrentUser(this.find('.gfm-project_member').get());
   initUserPopovers(this.find('.gfm-project_member').get());
+  initMRPopovers(this.find('.gfm-merge_request').get());
   return this;
 };
 
diff --git a/app/assets/javascripts/mr_popover/components/mr_popover.vue b/app/assets/javascripts/mr_popover/components/mr_popover.vue
new file mode 100644
index 00000000000..8e2d8fa816a
--- /dev/null
+++ b/app/assets/javascripts/mr_popover/components/mr_popover.vue
@@ -0,0 +1,110 @@
+<script>
+import { GlPopover, GlSkeletonLoading } from '@gitlab/ui';
+import Icon from '../../vue_shared/components/icon.vue';
+import CiIcon from '../../vue_shared/components/ci_icon.vue';
+import timeagoMixin from '../../vue_shared/mixins/timeago';
+import query from '../queries/merge_request.graphql';
+import { mrStates, humanMRStates } from '../constants';
+
+export default {
+  name: 'MRPopover',
+  components: {
+    GlPopover,
+    GlSkeletonLoading,
+    Icon,
+    CiIcon,
+  },
+  mixins: [timeagoMixin],
+  props: {
+    target: {
+      type: HTMLAnchorElement,
+      required: true,
+    },
+    projectPath: {
+      type: String,
+      required: true,
+    },
+    mergeRequestIID: {
+      type: String,
+      required: true,
+    },
+    mergeRequestTitle: {
+      type: String,
+      required: true,
+    },
+  },
+  data() {
+    return {
+      mergeRequest: {},
+    };
+  },
+  computed: {
+    detailedStatus() {
+      return this.mergeRequest.headPipeline && this.mergeRequest.headPipeline.detailedStatus;
+    },
+    formattedTime() {
+      return this.timeFormated(this.mergeRequest.createdAt);
+    },
+    statusBoxClass() {
+      switch (this.mergeRequest.state) {
+        case mrStates.merged:
+          return 'status-box-mr-merged';
+        case mrStates.closed:
+          return 'status-box-closed';
+        default:
+          return 'status-box-open';
+      }
+    },
+    stateHumanName() {
+      switch (this.mergeRequest.state) {
+        case mrStates.merged:
+          return humanMRStates.merged;
+        case mrStates.closed:
+          return humanMRStates.closed;
+        default:
+          return humanMRStates.open;
+      }
+    },
+    showDetails() {
+      return Object.keys(this.mergeRequest).length > 0;
+    },
+  },
+  apollo: {
+    mergeRequest: {
+      query,
+      update: data => data.project.mergeRequest,
+      variables() {
+        const { projectPath, mergeRequestIID } = this;
+
+        return {
+          projectPath,
+          mergeRequestIID,
+        };
+      },
+    },
+  },
+};
+</script>
+
+<template>
+  <gl-popover :target="target" boundary="viewport" placement="top" show>
+    <div class="mr-popover">
+      <div v-if="$apollo.loading">
+        <gl-skeleton-loading :lines="1" class="animation-container-small mt-1" />
+      </div>
+      <div v-else-if="showDetails" class="d-flex align-items-center justify-content-between">
+        <div class="d-inline-flex align-items-center">
+          <div :class="`issuable-status-box status-box ${statusBoxClass}`">
+            {{ stateHumanName }}
+          </div>
+          <span class="text-secondary">Opened <time v-text="formattedTime"></time></span>
+        </div>
+        <ci-icon v-if="detailedStatus" :status="detailedStatus" />
+      </div>
+      <h5 class="my-2">{{ mergeRequestTitle }}</h5>
+      <div class="text-secondary">
+        {{ `${projectPath}!${mergeRequestIID}` }}
+      </div>
+    </div>
+  </gl-popover>
+</template>
diff --git a/app/assets/javascripts/mr_popover/constants.js b/app/assets/javascripts/mr_popover/constants.js
new file mode 100644
index 00000000000..433df844c80
--- /dev/null
+++ b/app/assets/javascripts/mr_popover/constants.js
@@ -0,0 +1,10 @@
+export const mrStates = {
+  merged: 'merged',
+  closed: 'closed',
+};
+
+export const humanMRStates = {
+  merged: 'Merged',
+  closed: 'Closed',
+  open: 'Open',
+};
diff --git a/app/assets/javascripts/mr_popover/index.js b/app/assets/javascripts/mr_popover/index.js
new file mode 100644
index 00000000000..cc686b401d2
--- /dev/null
+++ b/app/assets/javascripts/mr_popover/index.js
@@ -0,0 +1,62 @@
+import Vue from 'vue';
+import VueApollo from 'vue-apollo';
+import MRPopover from './components/mr_popover.vue';
+import createDefaultClient from '~/lib/graphql';
+
+let renderedPopover;
+let renderFn;
+
+const handleUserPopoverMouseOut = ({ target }) => {
+  target.removeEventListener('mouseleave', handleUserPopoverMouseOut);
+
+  if (renderFn) {
+    clearTimeout(renderFn);
+  }
+  if (renderedPopover) {
+    renderedPopover.$destroy();
+    renderedPopover = null;
+  }
+};
+
+/**
+ * Adds a MergeRequestPopover component to the body, hands over as much data as the target element has in data attributes.
+ * loads based on data-project-path and data-iid more data about an MR from the API and sets it on the popover
+ */
+const handleMRPopoverMount = apolloProvider => ({ target }) => {
+  // Add listener to actually remove it again
+  target.addEventListener('mouseleave', handleUserPopoverMouseOut);
+
+  const { projectPath, mrTitle, iid } = target.dataset;
+  const mergeRequest = {};
+
+  renderFn = setTimeout(() => {
+    const MRPopoverComponent = Vue.extend(MRPopover);
+    renderedPopover = new MRPopoverComponent({
+      propsData: {
+        target,
+        projectPath,
+        mergeRequestIID: iid,
+        mergeRequest,
+        mergeRequestTitle: mrTitle,
+      },
+      apolloProvider,
+    });
+
+    renderedPopover.$mount();
+  }, 200); // 200ms delay so not every mouseover triggers Popover + API Call
+};
+
+export default elements => {
+  const mrLinks = elements || [...document.querySelectorAll('.gfm-merge_request')];
+  if (mrLinks.length > 0) {
+    Vue.use(VueApollo);
+
+    const apolloProvider = new VueApollo({
+      defaultClient: createDefaultClient(),
+    });
+
+    mrLinks.forEach(el => {
+      el.addEventListener('mouseenter', handleMRPopoverMount(apolloProvider));
+    });
+  }
+};
diff --git a/app/assets/javascripts/mr_popover/queries/merge_request.graphql b/app/assets/javascripts/mr_popover/queries/merge_request.graphql
new file mode 100644
index 00000000000..0bb9bc03bc7
--- /dev/null
+++ b/app/assets/javascripts/mr_popover/queries/merge_request.graphql
@@ -0,0 +1,14 @@
+query mergeRequest($projectPath: ID!, $mergeRequestIID: ID!) {
+  project(fullPath: $projectPath) {
+    mergeRequest(iid: $mergeRequestIID) {
+      createdAt
+      state
+      headPipeline {
+        detailedStatus {
+          icon
+          group
+        }
+      }
+    }
+  }
+}
diff --git a/app/assets/javascripts/vue_shared/components/ci_icon.vue b/app/assets/javascripts/vue_shared/components/ci_icon.vue
index e6f0a1c69cd..25f80219993 100644
--- a/app/assets/javascripts/vue_shared/components/ci_icon.vue
+++ b/app/assets/javascripts/vue_shared/components/ci_icon.vue
@@ -22,6 +22,7 @@ import Icon from '../../vue_shared/components/icon.vue';
  * - Jobs show view header
  * - Jobs show view sidebar
  * - Linked pipelines
+ * - Extended MR Popover
  */
 const validSizes = [8, 12, 16, 18, 24, 32, 48, 72];
 
diff --git a/app/assets/stylesheets/components/popover.scss b/app/assets/stylesheets/components/popover.scss
index 2f4d30fe923..7d46b262a69 100644
--- a/app/assets/stylesheets/components/popover.scss
+++ b/app/assets/stylesheets/components/popover.scss
@@ -7,3 +7,10 @@
     line-height: $gl-line-height;
   }
 }
+
+.mr-popover {
+  .text-secondary {
+    font-size: 12px;
+    line-height: 1.33;
+  }
+}
diff --git a/app/graphql/types/ci/detailed_status_type.rb b/app/graphql/types/ci/detailed_status_type.rb
new file mode 100644
index 00000000000..2987354b556
--- /dev/null
+++ b/app/graphql/types/ci/detailed_status_type.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+module Types
+  module Ci
+    class DetailedStatusType < BaseObject
+      graphql_name 'DetailedStatus'
+
+      field :group, GraphQL::STRING_TYPE, null: false
+      field :icon, GraphQL::STRING_TYPE, null: false
+      field :favicon, GraphQL::STRING_TYPE, null: false
+      field :details_path, GraphQL::STRING_TYPE, null: false
+      field :has_details, GraphQL::BOOLEAN_TYPE, null: false, method: :has_details?
+      field :label, GraphQL::STRING_TYPE, null: false
+      field :text, GraphQL::STRING_TYPE, null: false
+      field :tooltip, GraphQL::STRING_TYPE, null: false, method: :status_tooltip
+    end
+  end
+end
diff --git a/app/graphql/types/ci/pipeline_type.rb b/app/graphql/types/ci/pipeline_type.rb
index 2bbffad4563..18696293b97 100644
--- a/app/graphql/types/ci/pipeline_type.rb
+++ b/app/graphql/types/ci/pipeline_type.rb
@@ -13,6 +13,10 @@ module Types
       field :sha, GraphQL::STRING_TYPE, null: false
       field :before_sha, GraphQL::STRING_TYPE, null: true
       field :status, PipelineStatusEnum, null: false
+      field :detailed_status,
+            Types::Ci::DetailedStatusType,
+            null: false,
+            resolve: -> (obj, _args, ctx) { obj.detailed_status(ctx[:current_user]) }
       field :duration,
             GraphQL::INT_TYPE,
             null: true,
diff --git a/app/models/concerns/cache_markdown_field.rb b/app/models/concerns/cache_markdown_field.rb
index 1a8570b80c3..9aa947eceda 100644
--- a/app/models/concerns/cache_markdown_field.rb
+++ b/app/models/concerns/cache_markdown_field.rb
@@ -14,7 +14,7 @@ module CacheMarkdownField
 
   # Increment this number every time the renderer changes its output
   CACHE_COMMONMARK_VERSION_START  = 10
-  CACHE_COMMONMARK_VERSION        = 14
+  CACHE_COMMONMARK_VERSION        = 15
 
   # changes to these attributes cause the cache to be invalidates
   INVALIDATED_BY = %w[author project].freeze
diff --git a/changelogs/unreleased/54916-extended-tooltip-for-merge-request-links.yml b/changelogs/unreleased/54916-extended-tooltip-for-merge-request-links.yml
new file mode 100644
index 00000000000..7fd0bcd1c00
--- /dev/null
+++ b/changelogs/unreleased/54916-extended-tooltip-for-merge-request-links.yml
@@ -0,0 +1,5 @@
+---
+title: Add extended merge request tooltip
+merge_request: !25221
+author:
+type: added
diff --git a/lib/banzai/filter/abstract_reference_filter.rb b/lib/banzai/filter/abstract_reference_filter.rb
index 4764f8e1e19..5f8aca104aa 100644
--- a/lib/banzai/filter/abstract_reference_filter.rb
+++ b/lib/banzai/filter/abstract_reference_filter.rb
@@ -181,9 +181,10 @@ module Banzai
             title = object_link_title(object, matches)
             klass = reference_class(object_sym)
 
-            data = data_attributes_for(link_content || match, parent, object,
-                                       link_content: !!link_content,
-                                       link_reference: link_reference)
+            data_attributes = data_attributes_for(link_content || match, parent, object,
+                                                  link_content: !!link_content,
+                                                  link_reference: link_reference)
+            data = data_attribute(data_attributes)
 
             url =
               if matches.names.include?("url") && matches[:url]
@@ -206,13 +207,13 @@ module Banzai
       def data_attributes_for(text, parent, object, link_content: false, link_reference: false)
         object_parent_type = parent.is_a?(Group) ? :group : :project
 
-        data_attribute(
+        {
           original:             text,
           link:                 link_content,
           link_reference:       link_reference,
           object_parent_type => parent.id,
           object_sym =>         object.id
-        )
+        }
       end
 
       def object_link_text_extras(object, matches)
diff --git a/lib/banzai/filter/merge_request_reference_filter.rb b/lib/banzai/filter/merge_request_reference_filter.rb
index 7098767b583..f05902078dc 100644
--- a/lib/banzai/filter/merge_request_reference_filter.rb
+++ b/lib/banzai/filter/merge_request_reference_filter.rb
@@ -20,7 +20,9 @@ module Banzai
       end
 
       def object_link_title(object, matches)
-        object_link_commit_title(object, matches) || super
+        # The method will return `nil` if object is not a commit
+        # allowing for properly handling the extended MR Tooltip
+        object_link_commit_title(object, matches)
       end
 
       def object_link_text_extras(object, matches)
@@ -53,6 +55,14 @@ module Banzai
           .includes(target_project: :namespace)
       end
 
+      def reference_class(object_sym, options = {})
+        super(object_sym, tooltip: false)
+      end
+
+      def data_attributes_for(text, parent, object, data = {})
+        super.merge(project_path: parent.full_path, iid: object.iid, mr_title: object.title)
+      end
+
       private
 
       def object_link_commit_title(object, matches)
diff --git a/spec/frontend/mr_popover/__snapshots__/mr_popover_spec.js.snap b/spec/frontend/mr_popover/__snapshots__/mr_popover_spec.js.snap
new file mode 100644
index 00000000000..5f9f13d591d
--- /dev/null
+++ b/spec/frontend/mr_popover/__snapshots__/mr_popover_spec.js.snap
@@ -0,0 +1,93 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`MR Popover loaded state matches the snapshot 1`] = `
+<glpopover-stub
+  boundary="viewport"
+  placement="top"
+  show=""
+  target=""
+>
+  <div
+    class="mr-popover"
+  >
+    <div
+      class="d-flex align-items-center justify-content-between"
+    >
+      <div
+        class="d-inline-flex align-items-center"
+      >
+        <div
+          class="issuable-status-box status-box status-box-open"
+        >
+          
+          Open
+        
+        </div>
+         
+        <span
+          class="text-secondary"
+        >
+          Opened 
+          <time>
+            just now
+          </time>
+        </span>
+      </div>
+       
+      <ciicon-stub
+        cssclasses=""
+        size="16"
+        status="[object Object]"
+      />
+    </div>
+     
+    <h5
+      class="my-2"
+    >
+      MR Title
+    </h5>
+     
+    <div
+      class="text-secondary"
+    >
+      
+      foo/bar!1
+    
+    </div>
+  </div>
+</glpopover-stub>
+`;
+
+exports[`MR Popover shows skeleton-loader while apollo is loading 1`] = `
+<glpopover-stub
+  boundary="viewport"
+  placement="top"
+  show=""
+  target=""
+>
+  <div
+    class="mr-popover"
+  >
+    <div>
+      <glskeletonloading-stub
+        class="animation-container-small mt-1"
+        lines="1"
+      />
+    </div>
+     
+    <h5
+      class="my-2"
+    >
+      MR Title
+    </h5>
+     
+    <div
+      class="text-secondary"
+    >
+      
+      foo/bar!1
+    
+    </div>
+  </div>
+</glpopover-stub>
+`;
diff --git a/spec/frontend/mr_popover/mr_popover_spec.js b/spec/frontend/mr_popover/mr_popover_spec.js
new file mode 100644
index 00000000000..79ed4163010
--- /dev/null
+++ b/spec/frontend/mr_popover/mr_popover_spec.js
@@ -0,0 +1,61 @@
+import MRPopover from '~/mr_popover/components/mr_popover';
+import { shallowMount } from '@vue/test-utils';
+
+describe('MR Popover', () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = shallowMount(MRPopover, {
+      propsData: {
+        target: document.createElement('a'),
+        projectPath: 'foo/bar',
+        mergeRequestIID: '1',
+        mergeRequestTitle: 'MR Title',
+      },
+      mocks: {
+        $apollo: {
+          loading: false,
+        },
+      },
+    });
+  });
+
+  it('shows skeleton-loader while apollo is loading', () => {
+    wrapper.vm.$apollo.loading = true;
+
+    expect(wrapper.element).toMatchSnapshot();
+  });
+
+  describe('loaded state', () => {
+    it('matches the snapshot', () => {
+      wrapper.setData({
+        mergeRequest: {
+          state: 'opened',
+          createdAt: new Date(),
+          headPipeline: {
+            detailedStatus: {
+              group: 'success',
+              status: 'status_success',
+            },
+          },
+        },
+      });
+
+      expect(wrapper.element).toMatchSnapshot();
+    });
+
+    it('does not show CI Icon if there is no pipeline data', () => {
+      wrapper.setData({
+        mergeRequest: {
+          state: 'opened',
+          headPipeline: null,
+          stateHumanName: 'Open',
+          title: 'Merge Request Title',
+          createdAt: new Date(),
+        },
+      });
+
+      expect(wrapper.contains('ciicon-stub')).toBe(false);
+    });
+  });
+});
diff --git a/spec/graphql/types/ci/detailed_status_type_spec.rb b/spec/graphql/types/ci/detailed_status_type_spec.rb
new file mode 100644
index 00000000000..a21162adb42
--- /dev/null
+++ b/spec/graphql/types/ci/detailed_status_type_spec.rb
@@ -0,0 +1,11 @@
+require 'spec_helper'
+
+describe Types::Ci::DetailedStatusType do
+  it { expect(described_class.graphql_name).to eq('DetailedStatus') }
+
+  it "has all fields" do
+    expect(described_class).to have_graphql_fields(:group, :icon, :favicon,
+                                                   :details_path, :has_details,
+                                                   :label, :text, :tooltip)
+  end
+end
diff --git a/spec/lib/banzai/filter/merge_request_reference_filter_spec.rb b/spec/lib/banzai/filter/merge_request_reference_filter_spec.rb
index 55c41e55437..72dfd6ff9ea 100644
--- a/spec/lib/banzai/filter/merge_request_reference_filter_spec.rb
+++ b/spec/lib/banzai/filter/merge_request_reference_filter_spec.rb
@@ -30,6 +30,23 @@ describe Banzai::Filter::MergeRequestReferenceFilter do
     end
   end
 
+  describe 'all references' do
+    let(:doc) { reference_filter(merge.to_reference) }
+    let(:tag_el) { doc.css('a').first }
+
+    it 'adds merge request iid' do
+      expect(tag_el["data-iid"]).to eq(merge.iid.to_s)
+    end
+
+    it 'adds project data attribute with project id' do
+      expect(tag_el["data-project-path"]).to eq(project.full_path)
+    end
+
+    it 'does not add `has-tooltip` class' do
+      expect(tag_el["class"]).not_to include('has-tooltip')
+    end
+  end
+
   context 'internal reference' do
     let(:reference) { merge.to_reference }
 
@@ -57,9 +74,9 @@ describe Banzai::Filter::MergeRequestReferenceFilter do
       expect(reference_filter(act).to_html).to eq exp
     end
 
-    it 'includes a title attribute' do
+    it 'has no title' do
       doc = reference_filter("Merge #{reference}")
-      expect(doc.css('a').first.attr('title')).to eq merge.title
+      expect(doc.css('a').first.attr('title')).to eq ""
     end
 
     it 'escapes the title attribute' do
@@ -69,9 +86,9 @@ describe Banzai::Filter::MergeRequestReferenceFilter do
       expect(doc.text).to eq "Merge #{reference}"
     end
 
-    it 'includes default classes' do
+    it 'includes default classes, without tooltip' do
       doc = reference_filter("Merge #{reference}")
-      expect(doc.css('a').first.attr('class')).to eq 'gfm gfm-merge_request has-tooltip'
+      expect(doc.css('a').first.attr('class')).to eq 'gfm gfm-merge_request'
     end
 
     it 'includes a data-project attribute' do
diff --git a/spec/requests/api/graphql/project/merge_request_spec.rb b/spec/requests/api/graphql/project/merge_request_spec.rb
index deb6abbc026..74820d39102 100644
--- a/spec/requests/api/graphql/project/merge_request_spec.rb
+++ b/spec/requests/api/graphql/project/merge_request_spec.rb
@@ -70,13 +70,13 @@ describe 'getting merge request information nested in a project' do
 
   context 'when there are pipelines' do
     before do
-      pipeline = create(
+      create(
         :ci_pipeline,
         project: merge_request.source_project,
         ref: merge_request.source_branch,
         sha: merge_request.diff_head_sha
       )
-      merge_request.update!(head_pipeline: pipeline)
+      merge_request.update_head_pipeline
     end
 
     it 'has a head pipeline' do