Use Rails' serialisation instead of JSON

app/models/repository.rb

@@ -65,6 +65,8 @@ class Repository
     xcode_config: :xcode_project?
   }.freeze
 
+  MERGED_BRANCH_NAMES_CACHE_DURATION = 10.minutes
+
   def initialize(full_path, project, disk_path: nil, repo_type: Gitlab::GlRepository::PROJECT)
     @full_path = full_path
     @disk_path = disk_path || full_path
@@ -923,7 +925,7 @@ class Repository
     return raw_repository.merged_branch_names(branch_names) if skip_cache
 
     cached_branch_names = cache.read(:merged_branch_names)
-    merged_branch_names_hash = cached_branch_names.present? ? JSON.parse(cached_branch_names) : {}
+    merged_branch_names_hash = cached_branch_names || {}
     missing_branch_names = branch_names.select { |bn| !merged_branch_names_hash.key?(bn) }
 
     # Track some metrics here whilst feature flag is enabled
@@ -935,17 +937,17 @@ class Repository
       counter.increment(full_hit: missing_branch_names.empty?)
     end
 
-    unless missing_branch_names.empty?
+    if missing_branch_names.any?
       merged = raw_repository.merged_branch_names(missing_branch_names)
 
       missing_branch_names.each do |bn|
-        merged_branch_names_hash[bn] = merged.include?(bn).to_s
+        merged_branch_names_hash[bn] = merged.include?(bn)
       end
 
-      cache.write(:merged_branch_names, merged_branch_names_hash.to_json, expires_in: 10.minutes)
+      cache.write(:merged_branch_names, merged_branch_names_hash, expires_in: MERGED_BRANCH_NAMES_CACHE_DURATION)
     end
 
-    Set.new(merged_branch_names_hash.select { |k, v| v.to_s == "true" }.keys)
+    Set.new(merged_branch_names_hash.select { |_, v| v }.keys)
   end
 
   def merge_base(*commits_or_ids)

spec/models/repository_spec.rb

@@ -502,10 +502,10 @@ describe Repository do
 
     let(:merge_state_hash) do
       {
-        "test" => "false",
-        "beep" => "false",
-        "boop" => "false",
-        "definitely_merged" => "true"
+        "test" => false,
+        "beep" => false,
+        "boop" => false,
+        "definitely_merged" => true
       }
     end
 
@@ -538,7 +538,7 @@ describe Repository do
 
       describe "cache values" do
         it "writes the values to redis" do
-          expect(cache).to receive(:write).with(cache_key, merge_state_hash.to_json, expires_in: 10.minutes)
+          expect(cache).to receive(:write).with(cache_key, merge_state_hash, expires_in: Repository::MERGED_BRANCH_NAMES_CACHE_DURATION)
 
           subject
         end
@@ -546,20 +546,21 @@ describe Repository do
         it "matches the supplied hash" do
           subject
 
-          expect(JSON.parse(cache.read(cache_key))).to eq(merge_state_hash)
+          expect(cache.read(cache_key)).to eq(merge_state_hash)
         end
       end
     end
 
     context "cache is not empty" do
       before do
-        cache.write(cache_key, merge_state_hash.to_json)
+        cache.write(cache_key, merge_state_hash)
       end
 
       it { is_expected.to eq(already_merged) }
 
       it "doesn't fetch from the disk" do
         expect(repository.raw_repository).not_to receive(:merged_branch_names)
+
         subject
       end
     end
@@ -568,13 +569,14 @@ describe Repository do
       before do
         allow(repository.raw_repository).to receive(:merged_branch_names).with(["boop"]).and_return([])
         hash = merge_state_hash.except("boop")
-        cache.write(cache_key, hash.to_json)
+        cache.write(cache_key, hash)
       end
 
       it { is_expected.to eq(already_merged) }
 
       it "does fetch from the disk" do
         expect(repository.raw_repository).to receive(:merged_branch_names).with(["boop"])
+
         subject
       end
     end