User not defined in PostReceive#process_project_changes

When Gitlab::GitPostReceive#changes_refs is empty
user would not get defined and nil would be passed
to PostReceive#after_project_changes_hooks which would
then throw an error.

app/workers/post_receive.rb

@@ -29,14 +29,11 @@ class PostReceive
   def process_project_changes(post_received)
     changes = []
     refs = Set.new
+    @user = post_received.identify
 
     post_received.changes_refs do |oldrev, newrev, ref|
       @user ||= post_received.identify(newrev)
-
-      unless @user
-        log("Triggered hook for non-existing user \"#{post_received.identifier}\"")
-        return false # rubocop:disable Cop/AvoidReturnFromBlocks
-      end
+      break unless @user
 
       if Gitlab::Git.tag_ref?(ref)
         GitTagPushService.new(post_received.project, @user, oldrev: oldrev, newrev: newrev, ref: ref).execute
@@ -48,6 +45,11 @@ class PostReceive
       refs << ref
     end
 
+    unless @user
+      log("Triggered hook for non-existing user \"#{post_received.identifier}\"")
+      return false
+    end
+
     after_project_changes_hooks(post_received, @user, refs.to_a, changes)
   end
 

changelogs/unreleased/51335-fail-early-when-user-cannot-be-identified.yml

+---
+title: If user was not found, service hooks won't run on post receive background job
+merge_request: 22519
+author:
+type: fixed

lib/gitlab/git_post_receive.rb

@@ -11,7 +11,7 @@ module Gitlab
       @changes = deserialize_changes(changes)
     end
 
-    def identify(revision)
+    def identify(revision = nil)
       super(identifier, project, revision)
     end
 

spec/workers/post_receive_spec.rb

@@ -6,7 +6,7 @@ describe PostReceive do
   let(:base64_changes) { Base64.encode64(wrongly_encoded_changes) }
   let(:gl_repository) { "project-#{project.id}" }
   let(:key) { create(:key, user: project.owner) }
-  let(:key_id) { key.shell_id }
+  let!(:key_id) { key.shell_id }
 
   let(:project) do
     create(:project, :repository, auto_cancel_pending_pipelines: 'disabled')
@@ -31,85 +31,97 @@ describe PostReceive do
   end
 
   describe "#process_project_changes" do
-    before do
-      allow_any_instance_of(Gitlab::GitPostReceive).to receive(:identify).and_return(project.owner)
+    context 'empty changes' do
+      it "does not call any PushService but runs after project hooks" do
+        expect(GitPushService).not_to receive(:new)
+        expect(GitTagPushService).not_to receive(:new)
+        expect_next_instance_of(SystemHooksService) { |service| expect(service).to receive(:execute_hooks) }
+
+        described_class.new.perform(gl_repository, key_id, "")
+      end
     end
 
-    context "branches" do
-      let(:changes) { "123456 789012 refs/heads/tést" }
+    context 'with changes' do
+      before do
+        allow_any_instance_of(Gitlab::GitPostReceive).to receive(:identify).and_return(project.owner)
+      end
+
+      context "branches" do
+        let(:changes) { "123456 789012 refs/heads/tést" }
 
-      it "calls GitTagPushService" do
-        expect_any_instance_of(GitPushService).to receive(:execute).and_return(true)
-        expect_any_instance_of(GitTagPushService).not_to receive(:execute)
-        described_class.new.perform(gl_repository, key_id, base64_changes)
+        it "calls GitPushService" do
+          expect_any_instance_of(GitPushService).to receive(:execute).and_return(true)
+          expect_any_instance_of(GitTagPushService).not_to receive(:execute)
+          described_class.new.perform(gl_repository, key_id, base64_changes)
+        end
       end
-    end
 
-    context "tags" do
-      let(:changes) { "123456 789012 refs/tags/tag" }
+      context "tags" do
+        let(:changes) { "123456 789012 refs/tags/tag" }
 
-      it "calls GitTagPushService" do
-        expect_any_instance_of(GitPushService).not_to receive(:execute)
-        expect_any_instance_of(GitTagPushService).to receive(:execute).and_return(true)
-        described_class.new.perform(gl_repository, key_id, base64_changes)
+        it "calls GitTagPushService" do
+          expect_any_instance_of(GitPushService).not_to receive(:execute)
+          expect_any_instance_of(GitTagPushService).to receive(:execute).and_return(true)
+          described_class.new.perform(gl_repository, key_id, base64_changes)
+        end
       end
-    end
 
-    context "merge-requests" do
-      let(:changes) { "123456 789012 refs/merge-requests/123" }
+      context "merge-requests" do
+        let(:changes) { "123456 789012 refs/merge-requests/123" }
 
-      it "does not call any of the services" do
-        expect_any_instance_of(GitPushService).not_to receive(:execute)
-        expect_any_instance_of(GitTagPushService).not_to receive(:execute)
-        described_class.new.perform(gl_repository, key_id, base64_changes)
+        it "does not call any of the services" do
+          expect_any_instance_of(GitPushService).not_to receive(:execute)
+          expect_any_instance_of(GitTagPushService).not_to receive(:execute)
+          described_class.new.perform(gl_repository, key_id, base64_changes)
+        end
       end
-    end
 
-    context "gitlab-ci.yml" do
-      let(:changes) { "123456 789012 refs/heads/feature\n654321 210987 refs/tags/tag" }
+      context "gitlab-ci.yml" do
+        let(:changes) { "123456 789012 refs/heads/feature\n654321 210987 refs/tags/tag" }
 
-      subject { described_class.new.perform(gl_repository, key_id, base64_changes) }
+        subject { described_class.new.perform(gl_repository, key_id, base64_changes) }
 
-      context "creates a Ci::Pipeline for every change" do
-        before do
-          stub_ci_pipeline_to_return_yaml_file
+        context "creates a Ci::Pipeline for every change" do
+          before do
+            stub_ci_pipeline_to_return_yaml_file
+
+            allow_any_instance_of(Project)
+              .to receive(:commit)
+              .and_return(project.commit)
 
-          allow_any_instance_of(Project)
-            .to receive(:commit)
-            .and_return(project.commit)
+            allow_any_instance_of(Repository)
+              .to receive(:branch_exists?)
+              .and_return(true)
+          end
 
-          allow_any_instance_of(Repository)
-            .to receive(:branch_exists?)
-            .and_return(true)
+          it { expect { subject }.to change { Ci::Pipeline.count }.by(2) }
         end
 
-        it { expect { subject }.to change { Ci::Pipeline.count }.by(2) }
-      end
+        context "does not create a Ci::Pipeline" do
+          before do
+            stub_ci_pipeline_yaml_file(nil)
+          end
 
-      context "does not create a Ci::Pipeline" do
-        before do
-          stub_ci_pipeline_yaml_file(nil)
+          it { expect { subject }.not_to change { Ci::Pipeline.count } }
         end
-
-        it { expect { subject }.not_to change { Ci::Pipeline.count } }
       end
-    end
 
-    context 'after project changes hooks' do
-      let(:changes) { '123456 789012 refs/heads/tést' }
-      let(:fake_hook_data) { Hash.new(event_name: 'repository_update') }
+      context 'after project changes hooks' do
+        let(:changes) { '123456 789012 refs/heads/tést' }
+        let(:fake_hook_data) { Hash.new(event_name: 'repository_update') }
 
-      before do
-        allow_any_instance_of(Gitlab::DataBuilder::Repository).to receive(:update).and_return(fake_hook_data)
-        # silence hooks so we can isolate
-        allow_any_instance_of(Key).to receive(:post_create_hook).and_return(true)
-        allow_any_instance_of(GitPushService).to receive(:execute).and_return(true)
-      end
+        before do
+          allow_any_instance_of(Gitlab::DataBuilder::Repository).to receive(:update).and_return(fake_hook_data)
+          # silence hooks so we can isolate
+          allow_any_instance_of(Key).to receive(:post_create_hook).and_return(true)
+          allow_any_instance_of(GitPushService).to receive(:execute).and_return(true)
+        end
 
-      it 'calls SystemHooksService' do
-        expect_any_instance_of(SystemHooksService).to receive(:execute_hooks).with(fake_hook_data, :repository_update_hooks).and_return(true)
+        it 'calls SystemHooksService' do
+          expect_any_instance_of(SystemHooksService).to receive(:execute_hooks).with(fake_hook_data, :repository_update_hooks).and_return(true)
 
-        described_class.new.perform(gl_repository, key_id, base64_changes)
+          described_class.new.perform(gl_repository, key_id, base64_changes)
+        end
       end
     end
   end