Mirroring to remote repository no longer fails after a force push.

GITLAB_SHELL_VERSION

-5.9.0
+5.9.1

app/services/projects/update_remote_mirror_service.rb

@@ -11,10 +11,6 @@ module Projects
       begin
         repository.fetch_remote(mirror.ref_name, no_tags: true)
 
-        if divergent_branches.present?
-          errors << "The following branches have diverged from their local counterparts: #{divergent_branches.to_sentence}"
-        end
-
         push_branches if changed_branches.present?
         delete_branches if deleted_branches.present?
 
@@ -70,15 +66,7 @@ module Projects
           branches << name
         elsif branch.dereferenced_target == remote_branch.dereferenced_target
           # Already up to date
-        elsif !repository.upstream_has_diverged?(name, mirror.ref_name)
-          branches << name
-        end
-      end
-    end
-
-    def divergent_branches
-      remote_branches.each_with_object([]) do |(name, _), branches|
-        if local_branches[name] && repository.upstream_has_diverged?(name, mirror.ref_name)
+        else
           branches << name
         end
       end

changelogs/unreleased-ee/1834-mirroring-to-remote-repository-fails-after-a-force-push.yml

+---
+title: Mirroring to remote repository no longer fails after a force push.
+merge_request: 2919
+author:
+type: fixed

lib/gitlab/shell.rb

@@ -388,10 +388,14 @@ module Gitlab
     # Ex.
     #   push_remote_branches('upstream', 'feature')
     #
-    def push_remote_branches(storage, project_name, remote_name, branch_names)
-      args = [gitlab_shell_projects_path, 'push-branches', storage, "#{project_name}.git", remote_name, '600', *branch_names]
+    def push_remote_branches(storage, project_name, remote_name, branch_names, forced: true)
+      args = [gitlab_shell_projects_path, 'push-branches', storage, "#{project_name}.git", remote_name, '600']
+      args << '--force' if forced
+      args += [*branch_names]
+
       output, status = Popen.popen(args)
       raise Error, output unless status.zero?
+
       true
     end
 

spec/lib/gitlab/shell_spec.rb

@@ -77,16 +77,16 @@ describe Gitlab::Shell do
     end
 
     describe '#push_remote_branches' do
+      let!(:args) { [projects_path, 'push-branches', 'current/storage', 'project/path.git', 'new/storage', '600', '--force', 'master'] }
+
       it 'executes the command' do
-        expect(Gitlab::Popen).to receive(:popen)
-        .with([projects_path, 'push-branches', 'current/storage', 'project/path.git', 'new/storage', '600', 'master']).and_return([nil, 0])
+        expect(Gitlab::Popen).to receive(:popen).with(args).and_return([nil, 0])
 
         expect(gitlab_shell.push_remote_branches('current/storage', 'project/path', 'new/storage', ['master'])).to be true
       end
 
       it 'fails to execute the command' do
-        expect(Gitlab::Popen).to receive(:popen)
-        .with([projects_path, 'push-branches', 'current/storage', 'project/path.git', 'new/storage', '600', 'master']).and_return(["error", 1])
+        expect(Gitlab::Popen).to receive(:popen).with(args).and_return(["error", 1])
 
         expect { gitlab_shell.push_remote_branches('current/storage', 'project/path', 'new/storage', ['master']) }.to raise_error(Gitlab::Shell::Error, "error")
       end

spec/services/projects/update_remote_mirror_service_spec.rb

@@ -81,6 +81,21 @@ describe Projects::UpdateRemoteMirrorService do
         subject.execute(remote_mirror)
       end
 
+      context 'when branch exists in local and remote repo' do
+        context 'when it has diverged' do
+          it 'syncs branches' do
+            allow(repository).to receive(:fetch_remote) do
+              sync_remote(repository, remote_mirror.ref_name, local_branch_names)
+              update_remote_branch(repository, remote_mirror.ref_name, 'markdown')
+            end
+
+            expect(repository).to receive(:push_remote_branches).with(remote_mirror.ref_name, ['markdown'])
+
+            subject.execute(remote_mirror)
+          end
+        end
+      end
+
       describe 'for delete' do
         context 'when branch exists in local and remote repo' do
           it 'deletes the branch from remote repo' do
@@ -195,6 +210,14 @@ describe Projects::UpdateRemoteMirrorService do
     end
   end
 
+  def update_remote_branch(repository, remote_name, branch)
+    rugged = repository.rugged
+    masterrev = repository.find_branch('master').dereferenced_target.id
+
+    rugged.references.create("refs/remotes/#{remote_name}/#{branch}", masterrev, force: true)
+    repository.expire_branches_cache
+  end
+
   def update_branch(repository, branch)
     rugged = repository.rugged
     masterrev = repository.find_branch('master').dereferenced_target.id