1 files changed, 45 insertions, 27 deletions

diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 311ba1ce6bd..59416fb4b51 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -165,7 +165,7 @@ class MergeRequest < ApplicationRecord
   validates :source_branch, presence: true
   validates :target_project, presence: true
   validates :target_branch, presence: true
-  validates :merge_user, presence: true, if: :merge_when_pipeline_succeeds?, unless: :importing?
+  validates :merge_user, presence: true, if: :auto_merge_enabled?, unless: :importing?
   validate :validate_branches, unless: [:allow_broken, :importing?, :closed_without_fork?]
   validate :validate_fork, unless: :closed_without_fork?
   validate :validate_target_project, on: :create
@@ -196,6 +196,7 @@ class MergeRequest < ApplicationRecord
 
   alias_attribute :project, :target_project
   alias_attribute :project_id, :target_project_id
+  alias_attribute :auto_merge_enabled, :merge_when_pipeline_succeeds
 
   def self.reference_prefix
     '!'
@@ -391,7 +392,7 @@ class MergeRequest < ApplicationRecord
   def merge_participants
     participants = [author]
 
-    if merge_when_pipeline_succeeds? && !participants.include?(merge_user)
+    if auto_merge_enabled? && !participants.include?(merge_user)
       participants << merge_user
     end
 
@@ -588,6 +589,8 @@ class MergeRequest < ApplicationRecord
       return
     end
 
+    [:source_branch, :target_branch].each { |attr| validate_branch_name(attr) }
+
     if opened?
       similar_mrs = target_project
         .merge_requests
@@ -608,6 +611,16 @@ class MergeRequest < ApplicationRecord
     end
   end
 
+  def validate_branch_name(attr)
+    return unless changes_include?(attr)
+
+    branch = read_attribute(attr)
+
+    return unless branch
+
+    errors.add(attr) unless Gitlab::GitRefValidator.validate_merge_request_branch(branch)
+  end
+
   def validate_target_project
     return true if target_project.merge_requests_enabled?
 
@@ -712,19 +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
@@ -750,7 +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
@@ -765,15 +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
@@ -782,7 +783,7 @@ class MergeRequest < ApplicationRecord
     project.ff_merge_must_be_possible? && !ff_merge_possible?
   end
 
-  def can_cancel_merge_when_pipeline_succeeds?(current_user)
+  def can_cancel_auto_merge?(current_user)
     can_be_merged_by?(current_user) || self.author == current_user
   end
 
@@ -801,6 +802,16 @@ class MergeRequest < ApplicationRecord
     Gitlab::Utils.to_boolean(merge_params['force_remove_source_branch'])
   end
 
+  def auto_merge_strategy
+    return unless auto_merge_enabled?
+
+    merge_params['auto_merge_strategy'] || AutoMergeService::STRATEGY_MERGE_WHEN_PIPELINE_SUCCEEDS
+  end
+
+  def auto_merge_strategy=(strategy)
+    merge_params['auto_merge_strategy'] = strategy
+  end
+
   def remove_source_branch?
     should_remove_source_branch? || force_remove_source_branch?
   end
@@ -973,15 +984,16 @@ class MergeRequest < ApplicationRecord
     end
   end
 
-  def reset_merge_when_pipeline_succeeds
-    return unless merge_when_pipeline_succeeds?
+  def reset_auto_merge
+    return unless auto_merge_enabled?
 
-    self.merge_when_pipeline_succeeds = false
+    self.auto_merge_enabled = false
     self.merge_user = nil
     if merge_params
       merge_params.delete('should_remove_source_branch')
       merge_params.delete('commit_message')
       merge_params.delete('squash_commit_message')
+      merge_params.delete('auto_merge_strategy')
     end
 
     self.save
@@ -1090,6 +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