Add a feature flag to change maximum text highlight size to 1MB

config/feature_flags/development/one_megabyte_file_size_limit.yml

+---
+name: one_megabyte_file_size_limit
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/65167
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/334916
+milestone: '14.1'
+type: development
+group: group::code review
+default_enabled: false

lib/gitlab/highlight.rb

@@ -11,11 +11,9 @@ module Gitlab
     end
 
     def self.too_large?(size)
-      file_size_limit = Gitlab.config.extra['maximum_text_highlight_size_kilobytes']
+      return false unless size.to_i > self.file_size_limit
 
-      return false unless size.to_i > file_size_limit
-
-      over_highlight_size_limit.increment(source: "file size: #{file_size_limit}") if Feature.enabled?(:track_file_size_over_highlight_limit)
+      over_highlight_size_limit.increment(source: "file size: #{self.file_size_limit}") if Feature.enabled?(:track_file_size_over_highlight_limit)
 
       true
     end
@@ -51,6 +49,16 @@ module Gitlab
 
     attr_reader :context
 
+    def self.file_size_limit
+      if Feature.enabled?(:one_megabyte_file_size_limit)
+        1024.kilobytes
+      else
+        Gitlab.config.extra['maximum_text_highlight_size_kilobytes']
+      end
+    end
+
+    private_class_method :file_size_limit
+
     def custom_language
       return unless @language
 

spec/lib/gitlab/highlight_spec.rb

@@ -50,9 +50,16 @@ RSpec.describe Gitlab::Highlight do
       let(:result) { described_class.highlight(file_name, content) } # content is 44 bytes
 
       before do
+        stub_feature_flags(one_megabyte_file_size_limit: false)
         stub_config(extra: { 'maximum_text_highlight_size_kilobytes' => 0.0001 } ) # 1.024 bytes
       end
 
+      it 'confirm file size is 1MB when `one_megabyte_file_size_limit` is enabled' do
+        stub_feature_flags(one_megabyte_file_size_limit: true)
+        expect(described_class.too_large?(1024.kilobytes)).to eq(false)
+        expect(described_class.too_large?(1025.kilobytes)).to eq(true)
+      end
+
       it 'increments the metric for oversized files' do
         expect { result }.to change { over_highlight_size_limit('file size: 0.0001') }.by(1)
       end