Merge branch 'osw-sync-merge-ref-upon-mergeability-check' into 'master'

Automatically update MR merge-ref along merge status

Closes #58495

See merge request gitlab-org/gitlab-ce!28513

1 files changed, 15 insertions, 21 deletions

diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index ab914e84650..59416fb4b51 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -725,19 +725,16 @@ class MergeRequest < ApplicationRecord
 
     MergeRequests::ReloadDiffsService.new(self, current_user).execute
   end
-  # rubocop: enable CodeReuse/ServiceClass
-
-  def check_if_can_be_merged
-    return unless self.class.state_machines[:merge_status].check_state?(merge_status) && Gitlab::Database.read_write?
 
-    can_be_merged =
-      !broken? && project.repository.can_be_merged?(diff_head_sha, target_branch)
+  def check_mergeability
+    MergeRequests::MergeabilityCheckService.new(self).execute
+  end
+  # rubocop: enable CodeReuse/ServiceClass
 
-    if can_be_merged
-      mark_as_mergeable
-    else
-      mark_as_unmergeable
-    end
+  # Returns boolean indicating the merge_status should be rechecked in order to
+  # switch to either can_be_merged or cannot_be_merged.
+  def recheck_merge_status?
+    self.class.state_machines[:merge_status].check_state?(merge_status)
   end
 
   def merge_event
@@ -763,7 +760,7 @@ class MergeRequest < ApplicationRecord
   def mergeable?(skip_ci_check: false)
     return false unless mergeable_state?(skip_ci_check: skip_ci_check)
 
-    check_if_can_be_merged
+    check_mergeability
 
     can_be_merged? && !should_be_rebased?
   end
@@ -778,15 +775,6 @@ class MergeRequest < ApplicationRecord
     true
   end
 
-  def mergeable_to_ref?
-    return false unless mergeable_state?(skip_ci_check: true, skip_discussions_check: true)
-
-    # Given the `merge_ref_path` will have the same
-    # state the `target_branch` would have. Ideally
-    # we need to check if it can be merged to it.
-    project.repository.can_be_merged?(diff_head_sha, target_branch)
-  end
-
   def ff_merge_possible?
     project.repository.ancestor?(target_branch_sha, diff_head_sha)
   end
@@ -1114,6 +1102,12 @@ class MergeRequest < ApplicationRecord
     target_project.repository.fetch_source_branch!(source_project.repository, source_branch, ref_path)
   end
 
+  # Returns the current merge-ref HEAD commit.
+  #
+  def merge_ref_head
+    project.repository.commit(merge_ref_path)
+  end
+
   def ref_path
     "refs/#{Repository::REF_MERGE_REQUEST}/#{iid}/head"
   end