Gracefully handle case when keep-around references are corrupted or exist already

app/models/repository.rb

@@ -211,11 +211,20 @@ class Repository
 
     return if kept_around?(sha)
 
-    rugged.references.create(keep_around_ref_name(sha), sha)
+    # This will still fail if the file is corrupted (e.g. 0 bytes)
+    begin
+      rugged.references.create(keep_around_ref_name(sha), sha, force: true)
+    rescue Rugged::ReferenceError => ex
+      Rails.logger.error "Unable to create keep-around reference for repository #{path}: #{ex}"
+    end
   end
 
   def kept_around?(sha)
-    ref_exists?(keep_around_ref_name(sha))
+    begin
+      ref_exists?(keep_around_ref_name(sha))
+    rescue Rugged::ReferenceError
+      false
+    end
   end
 
   def tag_names

spec/models/repository_spec.rb

@@ -1164,10 +1164,30 @@ describe Repository, models: true do
   end
 
   describe "#keep_around" do
+    it "does not fail if we attempt to reference bad commit" do
+      expect(repository.kept_around?('abc1234')).to be_falsey
+    end
+
     it "stores a reference to the specified commit sha so it isn't garbage collected" do
       repository.keep_around(sample_commit.id)
 
       expect(repository.kept_around?(sample_commit.id)).to be_truthy
     end
+
+    it "attempting to call keep_around on truncated ref does not fail" do
+      repository.keep_around(sample_commit.id)
+      ref = repository.send(:keep_around_ref_name, sample_commit.id)
+      path = File.join(repository.path, ref)
+      # Corrupt the reference
+      File.truncate(path, 0)
+
+      expect(repository.kept_around?(sample_commit.id)).to be_falsey
+
+      repository.keep_around(sample_commit.id)
+
+      expect(repository.kept_around?(sample_commit.id)).to be_falsey
+
+      File.delete(path)
+    end
   end
 end