Move issue related_branches to service

Moves the related_branches method from Issue model
to RelatedBranchesService

3 files changed, 27 insertions, 19 deletions

diff --git a/app/controllers/projects/issues_controller.rb b/app/controllers/projects/issues_controller.rb
index 4e859de6fde..b06a6f3bb0d 100644
--- a/app/controllers/projects/issues_controller.rb
+++ b/app/controllers/projects/issues_controller.rb
@@ -127,7 +127,7 @@ class Projects::IssuesController < Projects::ApplicationController
   end
 
   def related_branches
-    @related_branches = @issue.related_branches(current_user)
+    @related_branches = Issues::RelatedBranchesService.new(project, current_user).execute(issue)
 
     respond_to do |format|
       format.json do
diff --git a/app/models/issue.rb b/app/models/issue.rb
index d13fbcf002c..4ace5d3ab97 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -170,24 +170,6 @@ class Issue < ActiveRecord::Base
     "#{project.to_reference(from, full: full)}#{reference}"
   end
 
-  # All branches containing the current issue's ID, except for
-  # those with a merge request open referencing the current issue.
-  # rubocop: disable CodeReuse/ServiceClass
-  def related_branches(current_user)
-    branches_with_iid = project.repository.branch_names.select do |branch|
-      branch =~ /\A#{iid}-(?!\d+-stable)/i
-    end
-
-    branches_with_merge_request =
-      Issues::ReferencedMergeRequestsService
-        .new(project, current_user)
-        .referenced_merge_requests(self)
-        .map(&:source_branch)
-
-    branches_with_iid - branches_with_merge_request
-  end
-  # rubocop: enable CodeReuse/ServiceClass
-
   def suggested_branch_name
     return to_branch_name unless project.repository.branch_exists?(to_branch_name)
 
diff --git a/app/services/issues/related_branches_service.rb b/app/services/issues/related_branches_service.rb
new file mode 100644
index 00000000000..76af482b7ac
--- /dev/null
+++ b/app/services/issues/related_branches_service.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+# This service fetches all branches containing the current issue's ID, except for
+# those with a merge request open referencing the current issue.
+module Issues
+  class RelatedBranchesService < Issues::BaseService
+    def execute(issue)
+      branches_with_iid_of(issue) - branches_with_merge_request_for(issue)
+    end
+
+    private
+
+    def branches_with_merge_request_for(issue)
+      Issues::ReferencedMergeRequestsService
+        .new(project, current_user)
+        .referenced_merge_requests(issue)
+        .map(&:source_branch)
+    end
+
+    def branches_with_iid_of(issue)
+      project.repository.branch_names.select do |branch|
+        branch =~ /\A#{issue.iid}-(?!\d+-stable)/i
+      end
+    end
+  end
+end