Avoid excessive recursive calls with Rugged TreeEntriessh-fix-rugged-tree-entries

The Rugged implementation was recursively scanning the repository to
create `flat_path` because the post-process step was being called from
with a loop. For large repositories, this was significantly slowing
things down. Break the call to `rugged_populate_flat_path` out of this
loop to make this work efficiently.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/59759

1 files changed, 12 insertions, 8 deletions

diff --git a/lib/gitlab/git/rugged_impl/tree.rb b/lib/gitlab/git/rugged_impl/tree.rb
index 0ebfd496695..bb13d114d46 100644
--- a/lib/gitlab/git/rugged_impl/tree.rb
+++ b/lib/gitlab/git/rugged_impl/tree.rb
@@ -15,12 +15,23 @@ module Gitlab
           override :tree_entries
           def tree_entries(repository, sha, path, recursive)
             if Feature.enabled?(:rugged_tree_entries)
-              tree_entries_from_rugged(repository, sha, path, recursive)
+              tree_entries_with_flat_path_from_rugged(repository, sha, path, recursive)
             else
               super
             end
           end
 
+          def tree_entries_with_flat_path_from_rugged(repository, sha, path, recursive)
+            tree_entries_from_rugged(repository, sha, path, recursive).tap do |entries|
+              # This was an optimization to reduce N+1 queries for Gitaly
+              # (https://gitlab.com/gitlab-org/gitaly/issues/530).  It
+              # used to be done lazily in the view via
+              # TreeHelper#flatten_tree, so it's possible there's a
+              # performance impact by loading this eagerly.
+              rugged_populate_flat_path(repository, sha, path, entries)
+            end
+          end
+
           def tree_entries_from_rugged(repository, sha, path, recursive)
             current_path_entries = get_tree_entries_from_rugged(repository, sha, path)
             ordered_entries = []
@@ -32,13 +43,6 @@ module Gitlab
                 ordered_entries.concat(tree_entries_from_rugged(repository, sha, entry.path, true))
               end
             end
-
-            # This was an optimization to reduce N+1 queries for Gitaly
-            # (https://gitlab.com/gitlab-org/gitaly/issues/530).  It
-            # used to be done lazily in the view via
-            # TreeHelper#flatten_tree, so it's possible there's a
-            # performance impact by loading this eagerly.
-            rugged_populate_flat_path(repository, sha, path, ordered_entries)
           end
 
           def rugged_populate_flat_path(repository, sha, path, entries)