Batch load only data from same repository when lazy object is accessed

By specifying `key`, we get a different lazy batch loader for each
repository, which means that accessing a lazy object from one repository
will only result in that repository's objects being fetched, not those
of other repositories, saving us some unnecessary Gitaly lookups.

1 files changed, 15 insertions, 6 deletions

diff --git a/spec/models/blob_spec.rb b/spec/models/blob_spec.rb
index 81e35e6c931..ed93f94d893 100644
--- a/spec/models/blob_spec.rb
+++ b/spec/models/blob_spec.rb
@@ -18,14 +18,23 @@ describe Blob do
 
   describe '.lazy' do
     let(:project) { create(:project, :repository) }
-    let(:commit) { project.commit_by(oid: 'e63f41fe459e62e1228fcef60d7189127aeba95a') }
+    let(:other_project) { create(:project, :repository) }
+    let(:commit_id) { 'e63f41fe459e62e1228fcef60d7189127aeba95a' }
 
-    it 'fetches all blobs when the first is accessed' do
-      changelog = described_class.lazy(project, commit.id, 'CHANGELOG')
-      contributing = described_class.lazy(project, commit.id, 'CONTRIBUTING.md')
+    it 'does not fetch blobs when none are accessed' do
+      expect(project.repository).not_to receive(:blobs_at)
 
-      expect(Gitlab::Git::Blob).to receive(:batch).once.and_call_original
-      expect(Gitlab::Git::Blob).not_to receive(:find)
+      described_class.lazy(project, commit_id, 'CHANGELOG')
+    end
+
+    it 'fetches all blobs for the same repository when one is accessed' do
+      expect(project.repository).to receive(:blobs_at).with([[commit_id, 'CHANGELOG'], [commit_id, 'CONTRIBUTING.md']]).once.and_call_original
+      expect(other_project.repository).not_to receive(:blobs_at)
+
+      changelog = described_class.lazy(project, commit_id, 'CHANGELOG')
+      contributing = described_class.lazy(project, commit_id, 'CONTRIBUTING.md')
+
+      described_class.lazy(other_project, commit_id, 'CHANGELOG')
 
       # Access property so the values are loaded
       changelog.id