Only allow to create a release if it does not exist yet

app/services/create_release_service.rb

@@ -8,12 +8,18 @@ class CreateReleaseService < BaseService
 
     # Only create a release if the tag exists
     if existing_tag
-      release = project.releases.find_or_initialize_by(tag: tag_name)
-      release.update_attributes(description: release_description)
+      release = project.releases.find_by(tag: tag_name)
+
+      if(release)
+        error('Release already exists', 409)
+      else
+        release = project.releases.new({ tag: tag_name, description: release_description })
+        release.save
 
         success(release)
+      end
     else
-      error('Tag does not exist')
+      error('Tag does not exist', 404)
     end
   end
 

doc/api/tags.md

@@ -87,7 +87,8 @@ It returns 200 if the operation succeed. In case of an error,
 ## Create a new release
 
 Add release notes to the existing git tag. It returns 201 if the release is
-created successfully. If the tag does not exist, 404 is returned.
+created successfully. If the tag does not exist, 404 is returned. If there
+already exists a release for the given tag, 409 is returned.
 
 ```
 POST /projects/:id/repository/tags/:tag_name/release

lib/api/tags.rb

@@ -47,7 +47,7 @@ module API
       #   tag_name (required) - The name of the tag
       #   description (required) - Release notes with markdown support
       # Example Request:
-      #   PUT /projects/:id/repository/tags/:tag_name/release
+      #   POST /projects/:id/repository/tags/:tag_name/release
       post ':id/repository/tags/:tag_name/release', requirements: { tag_name: /.*/ } do
         authorize_push_project
         required_attributes! [:description]
@@ -57,7 +57,7 @@ module API
         if result[:status] == :success
           present result[:release], with: Entities::Release
         else
-          render_api_error!(result[:message], 404)
+          render_api_error!(result[:message], result[:http_status])
         end
       end
     end

spec/requests/api/tags_spec.rb

@@ -28,10 +28,10 @@ describe API::API, api: true  do
       before do
         release = project.releases.find_or_initialize_by(tag: tag_name)
         release.update_attributes(description: description)
-        get api("/projects/#{project.id}/repository/tags", user)
       end
 
       it "should return an array of project tags with release info" do
+        get api("/projects/#{project.id}/repository/tags", user)
         expect(response.status).to eq(200)
         expect(json_response).to be_an Array
         expect(json_response.first['name']).to eq(tag_name)
@@ -139,5 +139,20 @@ describe API::API, api: true  do
       expect(response.status).to eq(404)
       expect(json_response['message']).to eq('Tag does not exist')
     end
+
+    context 'on tag with existing release' do
+      before do
+        release = project.releases.find_or_initialize_by(tag: tag_name)
+        release.update_attributes(description: description)
+      end
+
+      it 'should return 409 if there is already a release' do
+        post api("/projects/#{project.id}/repository/tags/#{tag_name}/release", user),
+          description: description
+
+        expect(response.status).to eq(409)
+        expect(json_response['message']).to eq('Release already exists')
+      end
+    end
   end
 end