API: Expose branch status

changelogs/unreleased/api-branch-status.yml

+---
+title: 'API: Expose merge status for branch API'
+merge_request:
+author: Robert Schilling

doc/api/branches.md

@@ -22,6 +22,7 @@ Example response:
 [
   {
     "name": "master",
+    "merged": false,
     "protected": true,
     "developers_can_push": false,
     "developers_can_merge": false,
@@ -65,6 +66,7 @@ Example response:
 ```json
 {
   "name": "master",
+  "merged": false,
   "protected": true,
   "developers_can_push": false,
   "developers_can_merge": false,
@@ -123,6 +125,7 @@ Example response:
     ]
   },
   "name": "master",
+  "merged": false,
   "protected": true,
   "developers_can_push": true,
   "developers_can_merge": true
@@ -166,6 +169,7 @@ Example response:
     ]
   },
   "name": "master",
+  "merged": false,
   "protected": false,
   "developers_can_push": false,
   "developers_can_merge": false
@@ -206,6 +210,7 @@ Example response:
     ]
   },
   "name": "newbranch",
+  "merged": false,
   "protected": false,
   "developers_can_push": false,
   "developers_can_merge": false

lib/api/entities.rb

@@ -141,8 +141,12 @@ module API
         options[:project].repository.commit(repo_branch.dereferenced_target)
       end
 
+      expose :merged do |repo_branch, options|
+        options[:project].repository.merged_to_root_ref?(repo_branch.name)
+      end
+
       expose :protected do |repo_branch, options|
-        options[:project].protected_branch? repo_branch.name
+        options[:project].protected_branch?(repo_branch.name)
       end
 
       expose :developers_can_push do |repo_branch, options|

spec/requests/api/branches_spec.rb

@@ -31,11 +31,22 @@ describe API::API, api: true  do
 
       expect(json_response['name']).to eq(branch_name)
       expect(json_response['commit']['id']).to eq(branch_sha)
+      expect(json_response['merged']).to eq(false)
       expect(json_response['protected']).to eq(false)
       expect(json_response['developers_can_push']).to eq(false)
       expect(json_response['developers_can_merge']).to eq(false)
     end
 
+    context 'on a merged branch' do
+      it "returns the branch information for a single branch" do
+        get api("/projects/#{project.id}/repository/branches/merge-test", user)
+
+        expect(response).to have_http_status(200)
+        expect(json_response['name']).to eq('merge-test')
+        expect(json_response['merged']).to eq(true)
+      end
+    end
+
     it "returns a 403 error if guest" do
       get api("/projects/#{project.id}/repository/branches", user2)
       expect(response).to have_http_status(403)