Allow creating protected branch when it doesn't exist

if user has either push or merge permissions

+ Change log entry for fix to creating a branch matching a wildcard fails

changelogs/unreleased/22638-creating-a-branch-matching-a-wildcard-fails.yml

+---
+title: Allow creating protected branches when user can merge to such branch
+merge_request: 8458
+author:

lib/gitlab/user_access.rb

@@ -35,7 +35,9 @@ module Gitlab
         return true if project.empty_repo? && project.user_can_push_to_empty_repo?(user)
         access_levels = project.protected_branches.matching(ref).map(&:push_access_levels).flatten
-        access_levels.any? { |access_level| access_level.check_access(user) }
+        has_access = access_levels.any? { |access_level| access_level.check_access(user) }
+
+        has_access || !project.repository.branch_exists?(ref) && can_merge_to_branch?(ref)
       else
         user.can?(:push_code, project)
       end

spec/lib/gitlab/user_access_spec.rb

@@ -66,7 +66,8 @@ describe Gitlab::UserAccess, lib: true do
     end
     describe 'push to protected branch' do
-      let(:branch) { create :protected_branch, project: project }
+      let(:branch) { create :protected_branch, project: project, name: "test" }
+      let(:not_existing_branch) { create :protected_branch, :developers_can_merge, project: project }
       it 'returns true if user is a master' do
         project.team << [user, :master]
@@ -85,6 +86,12 @@ describe Gitlab::UserAccess, lib: true do
         expect(access.can_push_to_branch?(branch.name)).to be_falsey
       end
+
+      it 'returns true if branch does not exist and user has permission to merge' do
+        project.team << [user, :developer]
+
+        expect(access.can_push_to_branch?(not_existing_branch.name)).to be_truthy
+      end
     end
     describe 'push to protected branch if allowed for developers' do