From 5b0210a0c8db13b6e538dfea7bc07d090224bbca Mon Sep 17 00:00:00 2001
From: Sean McGivern <sean@gitlab.com>
Date: Tue, 10 Jul 2018 17:11:31 +0100
Subject: [PATCH] Fix ProcessCommitWorker when upstream project is deleted

---
 app/workers/process_commit_worker.rb          |  5 ++-
 ...-project-with-upstream-project-deleted.yml |  5 +++
 spec/workers/process_commit_worker_spec.rb    | 40 ++++++++++++++++---
 3 files changed, 42 insertions(+), 8 deletions(-)
 create mode 100644 changelogs/unreleased/45592-nomethoderror-undefined-method-commit-for-nil-nilclass-in-sidekiq-caused-by-a-merge-commit-in-a-forked-project-with-upstream-project-deleted.yml

diff --git a/app/workers/process_commit_worker.rb b/app/workers/process_commit_worker.rb
index ed39b4a1ea8..c9f6df9b56d 100644
--- a/app/workers/process_commit_worker.rb
+++ b/app/workers/process_commit_worker.rb
@@ -79,9 +79,10 @@ class ProcessCommitWorker
   # Avoid reprocessing commits that already exist in the upstream
   # when project is forked. This will also prevent duplicated system notes.
   def commit_exists_in_upstream?(project, commit_hash)
-    return false unless project.forked?
+    upstream_project = project.fork_source
+
+    return false unless upstream_project
 
-    upstream_project = project.forked_from_project
     commit_id = commit_hash.with_indifferent_access[:id]
     upstream_project.commit(commit_id).present?
   end
diff --git a/changelogs/unreleased/45592-nomethoderror-undefined-method-commit-for-nil-nilclass-in-sidekiq-caused-by-a-merge-commit-in-a-forked-project-with-upstream-project-deleted.yml b/changelogs/unreleased/45592-nomethoderror-undefined-method-commit-for-nil-nilclass-in-sidekiq-caused-by-a-merge-commit-in-a-forked-project-with-upstream-project-deleted.yml
new file mode 100644
index 00000000000..6994a238074
--- /dev/null
+++ b/changelogs/unreleased/45592-nomethoderror-undefined-method-commit-for-nil-nilclass-in-sidekiq-caused-by-a-merge-commit-in-a-forked-project-with-upstream-project-deleted.yml
@@ -0,0 +1,5 @@
+---
+title: Process commits as normal in forks when the upstream project is deleted
+merge_request: 20534
+author:
+type: fixed
diff --git a/spec/workers/process_commit_worker_spec.rb b/spec/workers/process_commit_worker_spec.rb
index ac79d9c0ac1..2d071c181c2 100644
--- a/spec/workers/process_commit_worker_spec.rb
+++ b/spec/workers/process_commit_worker_spec.rb
@@ -1,6 +1,8 @@
 require 'spec_helper'
 
 describe ProcessCommitWorker do
+  include ProjectForksHelper
+
   let(:worker) { described_class.new }
   let(:user) { create(:user) }
   let(:project) { create(:project, :public, :repository) }
@@ -32,15 +34,41 @@ describe ProcessCommitWorker do
       worker.perform(project.id, user.id, commit.to_hash)
     end
 
-    context 'when commit already exists in upstream project' do
-      let(:forked) { create(:project, :public, :repository) }
+    context 'when the project is forked' do
+      context 'when commit already exists in the upstream project' do
+        it 'does not process the commit message' do
+          forked = fork_project(project, user, repository: true)
 
-      it 'does not process commit message' do
-        create(:forked_project_link, forked_to_project: forked, forked_from_project: project)
+          expect(worker).not_to receive(:process_commit_message)
 
-        expect(worker).not_to receive(:process_commit_message)
+          worker.perform(forked.id, user.id, forked.commit.to_hash)
+        end
+      end
 
-        worker.perform(forked.id, user.id, forked.commit.to_hash)
+      context 'when the commit does not exist in the upstream project' do
+        it 'processes the commit message' do
+          empty_project = create(:project, :public)
+          forked = fork_project(empty_project, user, repository: true)
+
+          TestEnv.copy_repo(forked,
+                            bare_repo: TestEnv.factory_repo_path_bare,
+                            refs: TestEnv::BRANCH_SHA)
+
+          expect(worker).to receive(:process_commit_message)
+
+          worker.perform(forked.id, user.id, forked.commit.to_hash)
+        end
+      end
+
+      context 'when the upstream project no longer exists' do
+        it 'processes the commit message' do
+          forked = fork_project(project, user, repository: true)
+          project.destroy!
+
+          expect(worker).to receive(:process_commit_message)
+
+          worker.perform(forked.id, user.id, forked.commit.to_hash)
+        end
       end
     end
   end