Port "revent commit authors from self approvaling MR"

https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9007

ee/app/models/approval_state.rb

@@ -20,15 +20,12 @@ class ApprovalState
 
   # Excludes the author if 'self-approval' isn't explicitly enabled on project settings.
   def self.filter_author(users, merge_request)
-    return users unless merge_request.author_id
     return users if merge_request.target_project.merge_requests_author_approval?
 
     if users.is_a?(ActiveRecord::Relation) && !users.loaded?
-      users.where.not(id: merge_request.author_id)
+      users.where.not(id: merge_request.authors)
     else
-      users.dup
-      users.delete(merge_request.author)
-      users
+      users - merge_request.authors
     end
   end
 
@@ -106,7 +103,7 @@ class ApprovalState
     # That is, they're included/excluded from that list accordingly.
     return true if unactioned_approvers.include?(user)
     # We can safely unauthorize authors if it reaches this guard clause.
-    return false if user == merge_request.author
+    return false if merge_request.authors.include?(user)
     return false unless user.can?(:update_merge_request, merge_request)
 
     any_approver_allowed? && merge_request.approvals.where(user: user).empty?

ee/spec/models/approval_state_spec.rb

@@ -27,15 +27,17 @@ describe ApprovalState do
 
   shared_examples 'filtering author' do
     before do
+      allow(merge_request).to receive(:authors).and_return([merge_request.author, create(:user, username: 'commiter')])
+
       project.update(merge_requests_author_approval: merge_requests_author_approval)
-      create_rule(users: [merge_request.author])
+      create_rule(users: merge_request.authors)
     end
 
     context 'when self approval is disabled' do
       let(:merge_requests_author_approval) { false }
 
-      it 'excludes author' do
-        expect(results).not_to include(merge_request.author)
+      it 'excludes authors' do
+        expect(results).not_to include(*merge_request.authors)
       end
     end
 
@@ -43,7 +45,7 @@ describe ApprovalState do
       let(:merge_requests_author_approval) { true }
 
       it 'includes author' do
-        expect(results).to include(merge_request.author)
+        expect(results).to include(*merge_request.authors)
       end
     end
   end