checks: Fix mismatch in `#new_commits()` signature

In commit 0a90028f (checks: Speed up retrieving commits via
quarantine directory, 2021-07-29), the Gitlab::Git::Repository class got
a new optional parameter `allow_quarnatine` for `#new_commits()`. The
commit forgot to amend the Repository model though to accept the same
parameter, which as a result leads to a runtime error when the access
checks try to load new commits.

Fix this issue by adding the missing parameter to the Repository model.
This commit also changes the changes access spec to call the original
function such that the bug would've been caught without the fix.

Changelog: fixed

app/models/repository.rb

@@ -168,8 +168,8 @@ class Repository
   end
 
   # Returns a list of commits that are not present in any reference
-  def new_commits(newrev)
-    commits = raw.new_commits(newrev)
+  def new_commits(newrev, allow_quarantine: false)
+    commits = raw.new_commits(newrev, allow_quarantine: allow_quarantine)
 
     ::Commit.decorate(commits, container)
   end

spec/lib/gitlab/checks/changes_access_spec.rb

@@ -60,7 +60,7 @@ RSpec.describe Gitlab::Checks::ChangesAccess do
 
   describe '#commits' do
     it 'calls #new_commits' do
-      expect(project.repository).to receive(:new_commits).and_return([])
+      expect(project.repository).to receive(:new_commits).and_call_original
 
       expect(subject.commits).to eq([])
     end

spec/models/repository_spec.rb

@@ -398,32 +398,47 @@ RSpec.describe Repository do
   end
 
   describe '#new_commits' do
-    let_it_be(:project) { create(:project, :repository) }
+    shared_examples '#new_commits' do
+      let_it_be(:project) { create(:project, :repository) }
 
-    let(:repository) { project.repository }
+      let(:repository) { project.repository }
 
-    subject { repository.new_commits(rev) }
+      subject { repository.new_commits(rev, allow_quarantine: allow_quarantine) }
 
-    context 'when there are no new commits' do
-      let(:rev) { repository.commit.id }
+      context 'when there are no new commits' do
+        let(:rev) { repository.commit.id }
 
-      it 'returns an empty array' do
-        expect(subject).to eq([])
+        it 'returns an empty array' do
+          expect(subject).to eq([])
+        end
       end
-    end
 
-    context 'when new commits are found' do
-      let(:branch) { 'orphaned-branch' }
-      let!(:rev) { repository.commit(branch).id }
+      context 'when new commits are found' do
+        let(:branch) { 'orphaned-branch' }
+        let!(:rev) { repository.commit(branch).id }
+        let(:allow_quarantine) { false }
 
-      it 'returns the commits' do
-        repository.delete_branch(branch)
+        it 'returns the commits' do
+          repository.delete_branch(branch)
 
-        expect(subject).not_to be_empty
-        expect(subject).to all( be_a(::Commit) )
-        expect(subject.size).to eq(1)
+          expect(subject).not_to be_empty
+          expect(subject).to all( be_a(::Commit) )
+          expect(subject.size).to eq(1)
+        end
       end
     end
+
+    context 'with quarantine' do
+      let(:allow_quarantine) { true }
+
+      it_behaves_like '#new_commits'
+    end
+
+    context 'without quarantine' do
+      let(:allow_quarantine) { false }
+
+      it_behaves_like '#new_commits'
+    end
   end
 
   describe '#commits_by' do