Show local issues and MRs in "This X closes... / closed by..." sentence

app/helpers/issues_helper.rb

@@ -84,7 +84,11 @@ module IssuesHelper
   end
 
   def merge_requests_sentence(merge_requests)
-    merge_requests.map(&:to_reference).to_sentence(last_word_connector: ', or ')
+    # Sorting based on the `!123` or `group/project!123` reference will sort
+    # local merge requests first.
+    merge_requests.map do |merge_request|
+      merge_request.to_reference(@project)
+    end.sort.to_sentence(last_word_connector: ', or ')
   end
 
   def url_to_emoji(name)

app/helpers/merge_requests_helper.rb

@@ -39,7 +39,11 @@ module MergeRequestsHelper
   end
 
   def issues_sentence(issues)
-    issues.map(&:to_reference).to_sentence
+    # Sorting based on the `#123` or `group/project#123` reference will sort
+    # local issues first.
+    issues.map do |issue|
+      issue.to_reference(@project)
+    end.sort.to_sentence
   end
 
   def mr_change_branches_path(merge_request)

app/models/merge_request.rb

@@ -316,7 +316,7 @@ class MergeRequest < ActiveRecord::Base
       issues = commits.flat_map { |c| c.closes_issues(current_user) }
       issues.push(*Gitlab::ClosingIssueExtractor.new(project, current_user).
                   closed_by_message(description))
-      issues.uniq.sort_by(&:id)
+      issues.uniq
     else
       []
     end

app/views/projects/issues/_closed_by_box.html.haml

 .issue-closed-by-widget
   = icon('check')
-  This issue will be closed automatically when merge request #{gfm(merge_requests_sentence(@closed_by_merge_requests.sort))} is accepted.
+  This issue will be closed automatically when merge request #{gfm(merge_requests_sentence(@closed_by_merge_requests))} is accepted.