Add releases API

This commit introduces Releases API under /api/v4/projects/:id/releases

* We are introducing release policies at project level.
* We are deprecating releases changes from tags, both api and web
interface.
* Tags::CreateService no longer create a release

This feature is controlled by :releases_page feature flag

4 files changed, 56 insertions, 35 deletions

diff --git a/app/services/commits/tag_service.rb b/app/services/commits/tag_service.rb
index 7961ba4d3c4..bb8cfb63f98 100644
--- a/app/services/commits/tag_service.rb
+++ b/app/services/commits/tag_service.rb
@@ -9,11 +9,10 @@ module Commits
 
       tag_name = params[:tag_name]
       message = params[:tag_message]
-      release_description = nil
 
       result = Tags::CreateService
         .new(commit.project, current_user)
-        .execute(tag_name, commit.sha, message, release_description)
+        .execute(tag_name, commit.sha, message)
 
       if result[:status] == :success
         tag = result[:tag]
diff --git a/app/services/create_release_service.rb b/app/services/create_release_service.rb
index ab2dc5337aa..223670a935d 100644
--- a/app/services/create_release_service.rb
+++ b/app/services/create_release_service.rb
@@ -1,35 +1,50 @@
 # frozen_string_literal: true
 
 class CreateReleaseService < BaseService
-  # rubocop: disable CodeReuse/ActiveRecord
-  def execute(tag_name, release_description)
+  def execute(tag_name, release_description, name: nil, ref: nil)
     repository = project.repository
-    existing_tag = repository.find_tag(tag_name)
-
-    # Only create a release if the tag exists
-    if existing_tag
-      release = project.releases.find_by(tag: tag_name)
-
-      if release
-        error('Release already exists', 409)
-      else
-        release = project.releases.create!(
-          tag: tag_name,
-          name: tag_name,
-          sha: existing_tag.dereferenced_target.sha,
-          author: current_user,
-          description: release_description
-        )
-
-        success(release)
-      end
+    tag = repository.find_tag(tag_name)
+
+    if tag.blank? && ref.present?
+      result = create_tag(tag_name, ref)
+      return result unless result[:status] == :success
+
+      tag = result[:tag]
+    end
+
+    if tag.present?
+      create_release(tag, name, release_description)
     else
       error('Tag does not exist', 404)
     end
   end
-  # rubocop: enable CodeReuse/ActiveRecord
 
   def success(release)
     super().merge(release: release)
   end
+
+  private
+
+  def create_release(tag, name, description)
+    release = project.releases.find_by(tag: tag.name) # rubocop: disable CodeReuse/ActiveRecord
+
+    if release
+      error('Release already exists', 409)
+    else
+      release = project.releases.create!(
+        tag: tag.name,
+        name: name || tag.name,
+        sha: tag.dereferenced_target.sha,
+        author: current_user,
+        description: description
+      )
+
+      success(release)
+    end
+  end
+
+  def create_tag(tag_name, ref)
+    Tags::CreateService.new(project, current_user)
+      .execute(tag_name, ref, nil)
+  end
 end
diff --git a/app/services/tags/create_service.rb b/app/services/tags/create_service.rb
index 6bb9bb3988e..4de6b2d2774 100644
--- a/app/services/tags/create_service.rb
+++ b/app/services/tags/create_service.rb
@@ -2,7 +2,7 @@
 
 module Tags
   class CreateService < BaseService
-    def execute(tag_name, target, message, release_description = nil)
+    def execute(tag_name, target, message)
       valid_tag = Gitlab::GitRefValidator.validate(tag_name)
       return error('Tag name invalid') unless valid_tag
 
@@ -20,10 +20,7 @@ module Tags
       end
 
       if new_tag
-        if release_description.present?
-          CreateReleaseService.new(@project, @current_user)
-            .execute(tag_name, release_description)
-        end
+        repository.expire_tags_cache
 
         success.merge(tag: new_tag)
       else
diff --git a/app/services/update_release_service.rb b/app/services/update_release_service.rb
index e2228ca026c..b51e72c7bfc 100644
--- a/app/services/update_release_service.rb
+++ b/app/services/update_release_service.rb
@@ -1,18 +1,28 @@
 # frozen_string_literal: true
 
 class UpdateReleaseService < BaseService
+  attr_accessor :tag_name
+
+  def initialize(project, user, tag_name, params)
+    super(project, user, params)
+
+    @tag_name = tag_name
+  end
+
   # rubocop: disable CodeReuse/ActiveRecord
-  def execute(tag_name, release_description)
+  def execute
     repository = project.repository
-    existing_tag = repository.find_tag(tag_name)
+    existing_tag = repository.find_tag(@tag_name)
 
     if existing_tag
-      release = project.releases.find_by(tag: tag_name)
+      release = project.releases.find_by(tag: @tag_name)
 
       if release
-        release.update(description: release_description)
-
-        success(release)
+        if release.update(params)
+          success(release)
+        else
+          error(release.errors.messages || '400 Bad request', 400)
+        end
       else
         error('Release does not exist', 404)
       end