Merge branch 'ci-commit-as-pipeline' into 'master'

Ci::Commit becomes a Pipeline object

1. Ci::Commit receives context: ref, :tag.
1. One Ci::Commit describes a one Pipeline
1. Pipeline is created from `.gitlab-ci.yml`
1. Pipeline is a ordered group of builds
1. We test MR against Pipeline
1. Pipelines have a separate view (https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3703)
1. Pipeline can be triggered from UI (https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3703)
1. Later we change `Trigger -> TriggerRequest -> Build` to `Trigger -> Pipeline` (future)
1. We add a Pipeline Hook that will be triggered on Pipeline status change  (future)
1. We extend notifications to use `Pipeline Hook` to send summary on pipeline changes (future)

After merging that I'll prepare a separate MR that will unify naming, database columns, table names:
```
Ci::Commit -> Pipeline
Ci::Build -> Build
CommitStatus -> Job
GenericCommitStatus -> ExternalJob

ci_commits -> pipelines
ci_builds -> jobs
```

This MR implements first 5 points.

This is made to solve this issue https://gitlab.com/gitlab-org/gitlab-ce/issues/14149.

See merge request !3653

1 files changed, 17 insertions, 4 deletions

diff --git a/lib/api/commit_statuses.rb b/lib/api/commit_statuses.rb
index 8e74e177ea0..7388ed2f4ea 100644
--- a/lib/api/commit_statuses.rb
+++ b/lib/api/commit_statuses.rb
@@ -21,10 +21,9 @@ module API
         authorize!(:read_commit_status, user_project)
 
         not_found!('Commit') unless user_project.commit(params[:sha])
-        ci_commit = user_project.ci_commit(params[:sha])
-        return [] unless ci_commit
 
-        statuses = ci_commit.statuses
+        ci_commits = user_project.ci_commits.where(sha: params[:sha])
+        statuses = ::CommitStatus.where(commit: ci_commits)
         statuses = statuses.latest unless parse_boolean(params[:all])
         statuses = statuses.where(ref: params[:ref]) if params[:ref].present?
         statuses = statuses.where(stage: params[:stage]) if params[:stage].present?
@@ -51,7 +50,21 @@ module API
         commit = @project.commit(params[:sha])
         not_found! 'Commit' unless commit
 
-        ci_commit = @project.ensure_ci_commit(commit.sha)
+        # Since the CommitStatus is attached to Ci::Commit (in the future Pipeline)
+        # We need to always have the pipeline object
+        # To have a valid pipeline object that can be attached to specific MR
+        # Other CI service needs to send `ref`
+        # If we don't receive it, we will attach the CommitStatus to
+        # the first found branch on that commit
+
+        ref = params[:ref]
+        unless ref
+          branches = @project.repository.branch_names_contains(commit.sha)
+          not_found! 'References for commit' if branches.none?
+          ref = branches.first
+        end
+
+        ci_commit = @project.ensure_ci_commit(commit.sha, ref)
 
         name = params[:name] || params[:context]
         status = GenericCommitStatus.running_or_pending.find_by(commit: ci_commit, name: name, ref: params[:ref])