Add related merge request count to api response

changelogs/unreleased/add-related-merge-request-count-to-api-response.yml

+---
+title: Add related merge request count to api response
+merge_request: 24974
+author:
+type: added

doc/api/issues.md

@@ -110,6 +110,7 @@ Example response:
       "labels" : [],
       "upvotes": 4,
       "downvotes": 0,
+      "merge_requests_count": 0,
       "user_notes_count": 1,
       "due_date": "2016-07-22",
       "web_url": "http://example.com/example/example/issues/6",
@@ -219,6 +220,7 @@ Example response:
       "labels" : [],
       "upvotes": 4,
       "downvotes": 0,
+      "merge_requests_count": 0,
       "id" : 41,
       "title" : "Ut commodi ullam eos dolores perferendis nihil sunt.",
       "updated_at" : "2016-01-04T15:31:46.176Z",
@@ -334,6 +336,7 @@ Example response:
       "labels" : [],
       "upvotes": 4,
       "downvotes": 0,
+      "merge_requests_count": 0,
       "id" : 41,
       "title" : "Ut commodi ullam eos dolores perferendis nihil sunt.",
       "updated_at" : "2016-01-04T15:31:46.176Z",
@@ -430,6 +433,7 @@ Example response:
    "labels" : [],
    "upvotes": 4,
    "downvotes": 0,
+   "merge_requests_count": 0,
    "id" : 41,
    "title" : "Ut commodi ullam eos dolores perferendis nihil sunt.",
    "updated_at" : "2016-01-04T15:31:46.176Z",
@@ -505,6 +509,7 @@ Example response:
    ],
    "upvotes": 4,
    "downvotes": 0,
+   "merge_requests_count": 0,
    "author" : {
       "name" : "Alexandra Bashirian",
       "avatar_url" : null,
@@ -604,6 +609,7 @@ Example response:
    ],
    "upvotes": 4,
    "downvotes": 0,
+   "merge_requests_count": 0,
    "id" : 85,
    "assignees" : [],
    "assignee" : null,
@@ -690,6 +696,7 @@ Example response:
   "labels": [],
   "upvotes": 4,
   "downvotes": 0,
+  "merge_requests_count": 0,
   "milestone": null,
   "assignees": [{
     "name": "Miss Monserrate Beier",
@@ -774,6 +781,7 @@ Example response:
   "labels": [],
   "upvotes": 4,
   "downvotes": 0,
+  "merge_requests_count": 0,
   "milestone": null,
   "assignees": [{
     "name": "Miss Monserrate Beier",
@@ -856,6 +864,7 @@ Example response:
   "labels": [],
   "upvotes": 4,
   "downvotes": 0,
+  "merge_requests_count": 0,
   "milestone": null,
   "assignee": {
     "name": "Edwardo Grady",
@@ -973,6 +982,7 @@ Example response:
     "user_notes_count": 7,
     "upvotes": 0,
     "downvotes": 0,
+    "merge_requests_count": 0,
     "due_date": null,
     "web_url": "http://example.com/example/example/issues/110",
     "confidential": false,

lib/api/entities.rb

@@ -557,6 +557,15 @@ module API
       expose :time_stats, using: 'API::Entities::IssuableTimeStats' do |issue|
         issue
       end
+
+      expose :merge_requests_count do |issue, options|
+        if options[:issuable_metadata]
+          # Avoids an N+1 query when metadata is included
+          options[:issuable_metadata][issue.id].merge_requests_count
+        else
+          issue.merge_requests_closing_issues.count
+        end
+      end
     end
     class Issue < IssueBasic

spec/requests/api/issues_spec.rb

@@ -421,6 +421,24 @@ describe API::Issues do
         expect(response).to have_gitlab_http_status(200)
         expect(response).to match_response_schema('public_api/v4/issues')
       end
+
+      it 'returns a related merge request count of 0 if there are no related merge requests' do
+        get api('/issues', user)
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to match_response_schema('public_api/v4/issues')
+        expect(json_response.first).to include('merge_requests_count' => 0)
+      end
+
+      it 'returns a related merge request count > 0 if there are related merge requests' do
+        create(:merge_requests_closing_issues, issue: issue)
+
+        get api('/issues', user)
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to match_response_schema('public_api/v4/issues')
+        expect(json_response.first).to include('merge_requests_count' => 1)
+      end
     end
   end