Merge branch 'fix-ci-commit-creation' into 'master'

Fix creation of Ci::Commit object which can lead to pending, failed in some scenarios

## What does this MR do?

If we use a new `project.ci_commits` it will add it to array, and some other services which can do a save on a project can lead to a scenario when `ci_commit` will be saved, where it should not be.

## What are the relevant issue numbers?

https://gitlab.com/gitlab-com/support-forum/issues/717 https://gitlab.com/gitlab-com/support-forum/issues/715 https://gitlab.com/gitlab-org/gitlab-ce/issues/17596 https://gitlab.com/gitlab-com/support-forum/issues/714 https://gitlab.com/gitlab-org/gitlab-ce/issues/13402

cc @rymai 


See merge request !4214

CHANGELOG

@@ -8,6 +8,7 @@ v 8.8.0 (unreleased)
   - Toggle sign-up confirmation emails in application settings
   - Project#open_branches has been cleaned up and no longer loads entire records into memory.
   - Escape HTML in commit titles in system note messages
+  - Fix creation of Ci::Commit object which can lead to pending, failed in some scenarios
   - Improve multiple branch push performance by memoizing permission checking
   - Log to application.log when an admin starts and stops impersonating a user
   - Changing the confidentiality of an issue now creates a new system note (Alex Moore-Niemi)

app/services/create_commit_builds_service.rb

@@ -18,19 +18,16 @@ class CreateCommitBuildsService
       return false
     end
 
-    commit = project.ci_commit(sha, ref)
-    unless commit
-      commit = project.ci_commits.new(sha: sha, ref: ref, before_sha: before_sha, tag: tag)
+    commit = Ci::Commit.new(project: project, sha: sha, ref: ref, before_sha: before_sha, tag: tag)
 
-      # Skip creating ci_commit when no gitlab-ci.yml is found
-      unless commit.ci_yaml_file
-        return false
-      end
-
-      # Create a new ci_commit
-      commit.save!
+    # Skip creating ci_commit when no gitlab-ci.yml is found
+    unless commit.ci_yaml_file
+      return false
     end
 
+    # Create a new ci_commit
+    commit.save!
+
     # Skip creating builds for commits that have [ci skip]
     unless commit.skip_ci?
       # Create builds for commit

spec/workers/post_receive_spec.rb

@@ -48,6 +48,22 @@ describe PostReceive do
         PostReceive.new.perform(pwd(project), key_id, base64_changes)
       end
     end
+
+    context "gitlab-ci.yml" do
+      subject { PostReceive.new.perform(pwd(project), key_id, base64_changes) }
+
+      context "creates a Ci::Commit for every change" do
+        before { stub_ci_commit_to_return_yaml_file }
+
+        it { expect{ subject }.to change{ Ci::Commit.count }.by(2) }
+      end
+
+      context "does not create a Ci::Commit" do
+        before { stub_ci_commit_yaml_file(nil) }
+
+        it { expect{ subject }.to_not change{ Ci::Commit.count } }
+      end
+    end
   end
 
   context "webhook" do