Omit max-count for diverging_commit_counts behind feature flag

We want to optimize the query for the CountDivergingCommits rpc by
removing the --max-count argument now that we have commit graphs
enabled for all repositories during housekeeping. However, we want to
test this first behind a feature flag.

1 files changed, 22 insertions, 1 deletions

diff --git a/app/models/repository.rb b/app/models/repository.rb
index be17b54ff12..5a003f25944 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -283,14 +283,19 @@ class Repository
   end
 
   def diverging_commit_counts(branch)
+    return diverging_commit_counts_without_max(branch) if Feature.enabled?('gitaly_count_diverging_commits_no_max')
+
+    ## TODO: deprecate the below code after 12.0
     @root_ref_hash ||= raw_repository.commit(root_ref).id
     cache.fetch(:"diverging_commit_counts_#{branch.name}") do
       # Rugged seems to throw a `ReferenceError` when given branch_names rather
       # than SHA-1 hashes
+      branch_sha = branch.dereferenced_target.sha
+
       number_commits_behind, number_commits_ahead =
         raw_repository.diverging_commit_count(
           @root_ref_hash,
-          branch.dereferenced_target.sha,
+          branch_sha,
           max_count: MAX_DIVERGING_COUNT)
 
       if number_commits_behind + number_commits_ahead >= MAX_DIVERGING_COUNT
@@ -301,6 +306,22 @@ class Repository
     end
   end
 
+  def diverging_commit_counts_without_max(branch)
+    @root_ref_hash ||= raw_repository.commit(root_ref).id
+    cache.fetch(:"diverging_commit_counts_without_max_#{branch.name}") do
+      # Rugged seems to throw a `ReferenceError` when given branch_names rather
+      # than SHA-1 hashes
+      branch_sha = branch.dereferenced_target.sha
+
+      number_commits_behind, number_commits_ahead =
+        raw_repository.diverging_commit_count(
+          @root_ref_hash,
+          branch_sha)
+
+      { behind: number_commits_behind, ahead: number_commits_ahead }
+    end
+  end
+
   def archive_metadata(ref, storage_path, format = "tar.gz", append_sha:, path: nil)
     raw_repository.archive_metadata(
       ref,