Batchload blobs for diff generation

After installing a new gem, batch-loader, a construct can be used to
queue data to be fetched in bulk. The gem was also introduced in both
gitlab-org/gitlab-ce!14680 and gitlab-org/gitlab-ce!14846, but those mrs
are not merged yet.

For the generation of diffs, both the old blob and the new blob need to
be loaded. This for every file in the diff, too. Now we collect all
these so we do 1 fetch. Three `.allow_n_plus_1_calls` have been removed,
which I expect to be valid, but this needs to be confirmed by a full CI
run.

Possibly closes:
- https://gitlab.com/gitlab-org/gitlab-ce/issues/37445
- https://gitlab.com/gitlab-org/gitlab-ce/issues/37599
- https://gitlab.com/gitlab-org/gitlab-ce/issues/37431

1 files changed, 2 insertions, 2 deletions

diff --git a/app/models/commit.rb b/app/models/commit.rb
index a31ebe9cc87..8401d99a08f 100644
--- a/app/models/commit.rb
+++ b/app/models/commit.rb
@@ -84,7 +84,7 @@ class Commit
   end
 
   def id
-    @raw.id
+    raw.id
   end
 
   def ==(other)
@@ -361,7 +361,7 @@ class Commit
     @deltas ||= raw.deltas
   end
 
-  def diffs(diff_options = nil)
+  def diffs(diff_options = {})
     Gitlab::Diff::FileCollection::Commit.new(self, diff_options: diff_options)
   end