Allow editing a release in API via PUT method

app/services/create_release_service.rb

@@ -10,7 +10,7 @@ class CreateReleaseService < BaseService
     if existing_tag
       release = project.releases.find_by(tag: tag_name)
 
-      if(release)
+      if release
         error('Release already exists', 409)
       else
         release = project.releases.new({ tag: tag_name, description: release_description })

app/services/update_release_service.rb

+require_relative 'base_service'
+
+class UpdateReleaseService < BaseService
+  def execute(tag_name, release_description)
+
+    repository = project.repository
+    existing_tag = repository.find_tag(tag_name)
+
+    if existing_tag
+      release = project.releases.find_by(tag: tag_name)
+
+      if release
+        release.update_attributes(description: release_description)
+
+        success(release)
+      else
+        error('Release does not exist', 404)
+      end
+    else
+      error('Tag does not exist', 404)
+    end
+  end
+
+  def success(release)
+    out = super()
+    out[:release] = release
+    out
+  end
+end

doc/api/tags.md

@@ -106,3 +106,26 @@ Parameters:
   "description": "Amazing release. Wow"
 }
 ```
+
+## Update a release
+
+Updates the release notes of a given release. It returns 200 if the release is
+successfully updated. If the tag or the release does not exist, it returns 404
+with a proper error message.
+
+```
+PUT /projects/:id/repository/tags/:tag_name/release
+```
+
+Parameters:
+
+- `id` (required) - The ID of a project
+- `tag_name` (required) - The name of a tag
+- `description` (required) - Release notes with markdown support
+
+```json
+{
+  "tag_name": "1.0.0",
+  "description": "Amazing release. Wow"
+}
+```
\ No newline at end of file

lib/api/tags.rb

@@ -60,6 +60,27 @@ module API
           render_api_error!(result[:message], result[:http_status])
         end
       end
+
+      # Updates a release notes of a tag
+      #
+      # Parameters:
+      #   id (required) - The ID of a project
+      #   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
+      put ':id/repository/tags/:tag_name/release', requirements: { tag_name: /.*/ } do
+        authorize_push_project
+        required_attributes! [:description]
+        result = UpdateReleaseService.new(user_project, current_user).
+          execute(params[:tag_name], params[:description])
+
+        if result[:status] == :success
+          present result[:release], with: Entities::Release
+        else
+          render_api_error!(result[:message], result[:http_status])
+        end
+      end
     end
   end
 end

spec/requests/api/tags_spec.rb

@@ -155,4 +155,42 @@ describe API::API, api: true  do
       end
     end
   end
+
+  describe 'PUT id/repository/tags/:tag_name/release' do
+    let(:tag_name) { project.repository.tag_names.first }
+    let(:description) { 'Awesome release!' }
+    let(:new_description) { 'The best release!' }
+
+    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 update the release description' do
+        put api("/projects/#{project.id}/repository/tags/#{tag_name}/release", user),
+          description: new_description
+
+        expect(response.status).to eq(200)
+        expect(json_response['tag_name']).to eq(tag_name)
+        expect(json_response['description']).to eq(new_description)
+      end
+    end
+
+    it 'should return 404 if the tag does not exist' do
+      put api("/projects/#{project.id}/repository/tags/foobar/release", user),
+        description: new_description
+
+      expect(response.status).to eq(404)
+      expect(json_response['message']).to eq('Tag does not exist')
+    end
+
+    it 'should return 404 if the release does not exist' do
+      put api("/projects/#{project.id}/repository/tags/#{tag_name}/release", user),
+        description: new_description
+
+      expect(response.status).to eq(404)
+      expect(json_response['message']).to eq('Release does not exist')
+    end
+  end
 end