Expire project caches once per push instead of once per ref

Previously `ProjectCacheWorker` would be scheduled once per ref, which
would generate unnecessary I/O and load on Sidekiq, especially if many
tags or branches were pushed at once. `ProjectCacheWorker` would expire
three items:

1. Repository size: This only needs to be updated once per push.
2. Commit count: This only needs to be updated if the default branch
   is updated.
3. Project method caches: This only needs to be updated if the default
   branch changes, but only if certain files change (e.g. README,
   CHANGELOG, etc.).

Because the third item requires looking at the actual changes in the
commit deltas, we schedule one `ProjectCacheWorker` to handle the first
two cases, and schedule a separate `ProjectCacheWorker` for the third
case if it is needed. As a result, this brings down the number of
`ProjectCacheWorker` jobs from N to 2.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/52046

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/gitlab/git_post_receive.rb b/lib/gitlab/git_post_receive.rb
index 24d752b8a4b..2a8bcd015a8 100644
--- a/lib/gitlab/git_post_receive.rb
+++ b/lib/gitlab/git_post_receive.rb
@@ -39,6 +39,17 @@ module Gitlab
       end
     end
 
+    def includes_default_branch?
+      # If the branch doesn't have a default branch yet, we presume the
+      # first branch pushed will be the default.
+      return true unless project.default_branch.present?
+
+      enum_for(:changes_refs).any? do |_oldrev, _newrev, ref|
+        Gitlab::Git.branch_ref?(ref) &&
+          Gitlab::Git.branch_name(ref) == project.default_branch
+      end
+    end
+
     private
 
     def deserialize_changes(changes)