1 files changed, 32 insertions, 0 deletions
diff --git a/lib/bundler/feature_flag.rb b/lib/bundler/feature_flag.rb
new file mode 100644
index 0000000000..150cac1e67
--- /dev/null
+++ b/lib/bundler/feature_flag.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+module Bundler
+  class FeatureFlag
+    def self.settings_flag(flag, &default)
+      unless Bundler::Settings::BOOL_KEYS.include?(flag.to_s)
+        raise "Cannot use `#{flag}` as a settings feature flag since it isn't a bool key"
+      end
+      define_method("#{flag}?") do
+        value = Bundler.settings[flag]
+        value = instance_eval(&default) if value.nil? && !default.nil?
+        value
+      end
+    end
+
+    (1..10).each {|v| define_method("bundler_#{v}_mode?") { major_version >= v } }
+
+    settings_flag(:allow_offline_install) { bundler_2_mode? }
+    settings_flag(:only_update_to_newer_versions) { bundler_2_mode? }
+    settings_flag(:plugins) { @bundler_version >= Gem::Version.new("1.14") }
+
+    def initialize(bundler_version)
+      @bundler_version = Gem::Version.create(bundler_version)
+    end
+
+    def major_version
+      @bundler_version.segments.first
+    end
+    private :major_version
+
+    class << self; private :settings_flag; end
+  end
+end