Add new methods to MR to check if source or target branch exists

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/projects/merge_requests_controller.rb

@@ -160,14 +160,17 @@ class Projects::MergeRequestsController < Projects::ApplicationController
   end
   def validates_merge_request
+    # If source project was removed (Ex. mr from fork to origin)
+    return invalid_mr unless @merge_request.source_project
+
     # Show git not found page
     # if there is no saved commits between source & target branch
     if @merge_request.commits.blank?
-       # and if source target doesn't exist
-       return invalid_mr unless @merge_request.target_project.repository.branch_names.include?(@merge_request.target_branch)
-       # or if source branch doesn't exist
-       return invalid_mr unless @merge_request.source_project.repository.branch_names.include?(@merge_request.source_branch)
+      # and if target branch doesn't exist
+      return invalid_mr unless @merge_request.target_branch_exists?
+      # or if source branch doesn't exist
+      return invalid_mr unless @merge_request.source_branch_exists?
     end
   end

app/models/merge_request.rb

@@ -262,7 +262,7 @@ class MergeRequest < ActiveRecord::Base
   # Return the set of issues that will be closed if this merge request is accepted.
   def closes_issues
     if target_branch == project.default_branch
-      unmerged_commits.map { |c| c.closes_issues(project) }.flatten.uniq.sort_by(&:id)
+      commits.map { |c| c.closes_issues(project) }.flatten.uniq.sort_by(&:id)
     else
       []
     end
@@ -273,6 +273,34 @@ class MergeRequest < ActiveRecord::Base
     "merge request !#{iid}"
   end
+  def target_project_path
+    if target_project
+      target_project.path_with_namespace
+    else
+      "(removed)"
+    end
+  end
+
+  def source_project_path
+    if source_project
+      source_project.path_with_namespace
+    else
+      "(removed)"
+    end
+  end
+
+  def source_branch_exists?
+    return false unless self.source_project
+
+    self.source_project.repository.branch_names.include?(self.source_branch)
+  end
+
+  def target_branch_exists?
+    return false unless self.target_project
+
+    self.target_project.repository.branch_names.include?(self.target_branch)
+  end
+
   private
   def dump_commits(commits)