Turn on Cat-File cache by default

The feature flag has been introduced an was turned off by default,
now the it will default to be turned on. That change would still allow
users to turn this feature off by leveraging the Rails console by
running:

`Feature.disable("gitaly_catfile-cache")`

Another option is to manage the number of items the LRU cache will
contain, by updating the `config.toml` for Gitaly. This would be the
`catfile_cache_size`:
https://gitlab.com/gitlab-org/gitaly/blob/0dcb5c579e63754f557aef91a4fa7a00e5b8b127/config.toml.example#L27

Closes: https://gitlab.com/gitlab-org/gitaly/issues/1712

lib/feature/gitaly.rb

+# frozen_string_literal: true
+
+require 'set'
+
 class Feature
   class Gitaly
+    # Server feature flags should use '_' to separate words.
+    # CATFILE_CACHE sets an incorrect example
     CATFILE_CACHE = 'catfile-cache'.freeze
 
-    # Server feature flags should use '_' to separate words.
     SERVER_FEATURE_FLAGS = [CATFILE_CACHE].freeze
+    DEFAULT_ON_FLAGS = Set.new([CATFILE_CACHE]).freeze
 
     class << self
       def enabled?(feature_flag)
-        Feature::FlipperFeature.table_exists? && Feature.enabled?("gitaly_#{feature_flag}")
+        return false unless Feature::FlipperFeature.table_exists?
+
+        default_on = DEFAULT_ON_FLAGS.include?(feature_flag)
+        Feature.enabled?("gitaly_#{feature_flag}", default_enabled: default_on)
       rescue ActiveRecord::NoDatabaseError
         false
       end
 
       def server_feature_flags
-        @server_feature_flags ||=
-          begin
         SERVER_FEATURE_FLAGS.map do |f|
           ["gitaly-feature-#{f.tr('_', '-')}", enabled?(f).to_s]
         end.to_h
       end
     end
   end
-  end
 end

lib/gitlab/gitaly_client.rb

@@ -240,7 +240,6 @@ module Gitlab
       Gitlab::SafeRequestStore[:gitaly_session_id] ||= SecureRandom.uuid
     end
 
-
     def self.token(storage)
       params = Gitlab.config.repositories.storages[storage]
       raise "storage not found: #{storage.inspect}" if params.nil?

lib/gitlab/gitaly_client/storage_settings.rb

@@ -34,7 +34,7 @@ module Gitlab
       def self.disk_access_denied?
         return false if rugged_enabled?
 
-        !temporarily_allowed?(ALLOW_KEY) && GitalyClient.feature_enabled?(DISK_ACCESS_DENIED_FLAG)
+        !temporarily_allowed?(ALLOW_KEY) && Feature::Gitaly.enabled?(DISK_ACCESS_DENIED_FLAG)
       rescue
         false # Err on the side of caution, don't break gitlab for people
       end

spec/lib/feature/gitaly_spec.rb

 require 'spec_helper'
 
 describe Feature::Gitaly do
-  let(:feature_flag) { "mepmep" }
+  let(:feature_flag) { "mep_mep" }
+
+  before do
+    stub_const("#{described_class}::SERVER_FEATURE_FLAGS", [feature_flag])
+  end
 
   describe ".enabled?" do
     context 'when the gate is closed' do
       before do
-        allow(Feature).to receive(:enabled?).with("gitaly_mepmep").and_return(false)
+        stub_feature_flags(gitaly_mep_mep: false)
       end
 
       it 'returns false' do
         expect(described_class.enabled?(feature_flag)).to be(false)
       end
     end
+
+    context 'when the flag defaults to on' do
+      it 'returns true' do
+        expect(described_class.enabled?(feature_flag)).to be(true)
+      end
+    end
   end
 
   describe ".server_feature_flags" do
+    context 'when one flag is disabled' do
       before do
-      stub_const("#{described_class}::SERVER_FEATURE_FLAGS", [feature_flag])
-      allow(Feature).to receive(:enabled?).with("gitaly_mepmep").and_return(false)
+        stub_feature_flags(gitaly_mep_mep: false)
       end
 
       subject { described_class.server_feature_flags }
 
       it { is_expected.to be_a(Hash) }
-
-    context 'when one flag is disabled' do
-      it { is_expected.to eq("gitaly-feature-mepmep" => "false") }
+      it { is_expected.to eq("gitaly-feature-mep-mep" => "false") }
     end
   end
 end

spec/lib/gitlab/gitaly_client/storage_settings_spec.rb

@@ -28,12 +28,16 @@ describe Gitlab::GitalyClient::StorageSettings do
   end
 
   describe '.disk_access_denied?' do
-    it 'return false when Rugged is enabled', :enable_rugged do
+    context 'when Rugged is enabled', :enable_rugged do
+      it 'returns false' do
         expect(described_class.disk_access_denied?).to be_falsey
       end
+    end
 
+    context 'when Rugged is disabled' do
       it 'returns true' do
         expect(described_class.disk_access_denied?).to be_truthy
       end
     end
+  end
 end

spec/support/helpers/cycle_analytics_helpers.rb

@@ -10,7 +10,7 @@ module CycleAnalyticsHelpers
     repository = project.repository
     oldrev = repository.commit(branch_name)&.sha || Gitlab::Git::BLANK_SHA
 
-    if Timecop.frozen? && Gitlab::GitalyClient.feature_enabled?(:operation_user_commit_files)
+    if Timecop.frozen?
       mock_gitaly_multi_action_dates(repository, commit_time)
     end