From c838243a90359d9570deb77f5889f809a5fd1997 Mon Sep 17 00:00:00 2001
From: Justin Tobler <jtobler@gitlab.com>
Date: Thu, 8 Feb 2024 16:28:10 -0600
Subject: [PATCH] repository: Disable file history rename detection

When viewing the commit history of a file, the `FindCommits` Gitaly RPC
is invoked with the `follow` option enabled. This instructs the
underlying `git-log(1)` operation to follow file renames when fetching
commit history. This rename detection can be rather expensive for
repositories with deep commit history and result in long file commit
history load times.

Introduce the `remove_file_commit_history_following` feature flag which,
when enabled, prevents rename detection from being performed when
finding commits for a single file.
---
 app/models/repository.rb                        |  2 +-
 .../remove_file_commit_history_following.yml    |  9 +++++++++
 spec/models/repository_spec.rb                  | 17 +++++++++++++++--
 3 files changed, 25 insertions(+), 3 deletions(-)
 create mode 100644 config/feature_flags/ops/remove_file_commit_history_following.yml

diff --git a/app/models/repository.rb b/app/models/repository.rb
index 6045b899743b5d..ae39056b774da4 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -153,7 +153,7 @@ def commits(ref = nil, opts = {})
       ref: ref,
       path: opts[:path],
       author: opts[:author],
-      follow: Array(opts[:path]).length == 1,
+      follow: Array(opts[:path]).length == 1 && Feature.disabled?(:remove_file_commit_history_following, type: :ops),
       limit: opts[:limit],
       offset: opts[:offset],
       skip_merges: !!opts[:skip_merges],
diff --git a/config/feature_flags/ops/remove_file_commit_history_following.yml b/config/feature_flags/ops/remove_file_commit_history_following.yml
new file mode 100644
index 00000000000000..872bcf1ab645ee
--- /dev/null
+++ b/config/feature_flags/ops/remove_file_commit_history_following.yml
@@ -0,0 +1,9 @@
+---
+name: remove_file_commit_history_following
+feature_issue_url: https://gitlab.com/gitlab-org/gitaly/-/issues/5821
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144263
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/441312
+milestone: '16.10'
+group: group::gitaly
+type: ops
+default_enabled: false
diff --git a/spec/models/repository_spec.rb b/spec/models/repository_spec.rb
index b6cb2464605d8c..25afbd625b306b 100644
--- a/spec/models/repository_spec.rb
+++ b/spec/models/repository_spec.rb
@@ -398,8 +398,21 @@ def expect_to_raise_storage_error
       end
 
       context 'with path' do
-        it 'sets follow when it is a single path' do
-          expect(Gitlab::Git::Commit).to receive(:where).with(a_hash_including(follow: true)).and_call_original.twice
+        context 'when remove_file_commit_history_following feature flag is disabled' do
+          before do
+            stub_feature_flags(remove_file_commit_history_following: false)
+          end
+
+          it 'sets follow when it is a single path' do
+            expect(Gitlab::Git::Commit).to receive(:where).with(a_hash_including(follow: true)).and_call_original.twice
+
+            repository.commits('master', limit: 1, path: 'README.md')
+            repository.commits('master', limit: 1, path: ['README.md'])
+          end
+        end
+
+        it 'does not set follow when it is a single path' do
+          expect(Gitlab::Git::Commit).to receive(:where).with(a_hash_including(follow: false)).and_call_original.twice
 
           repository.commits('master', limit: 1, path: 'README.md')
           repository.commits('master', limit: 1, path: ['README.md'])
-- 
GitLab