fix: support Hash#transform_keys for older Rubies

Author: palkan

lib/action_policy/ext/hash_transform_keys.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module ActionPolicy
+  module Ext
+    # Add transform_keys to Hash for older Rubys
+    module HashTransformKeys
+      refine Hash do
+        def transform_keys
+          return enum_for(:transform_keys) { size } unless block_given?
+          result = {}
+          each_key do |key|
+            result[yield(key)] = self[key]
+          end
+          result
+        end
+      end
+    end
+  end
+end

lib/action_policy/policy/cache.rb

@@ -9,7 +9,10 @@ module ActionPolicy # :nodoc:
   require "action_policy/ext/yield_self_then"
   require "action_policy/ext/policy_cache_key"
 
-  using ActionPolicy::Ext::YieldSelfThen
+  unless "".respond_to?(:then)
+    require "action_policy/ext/yield_self_then"
+    using ActionPolicy::Ext::YieldSelfThen
+  end
   using ActionPolicy::Ext::PolicyCacheKey
 
   module Policy

lib/action_policy/policy/reasons.rb

@@ -1,7 +1,14 @@
 # frozen_string_literal: true
 
-require "action_policy/ext/yield_self_then"
-using ActionPolicy::Ext::YieldSelfThen
+unless "".respond_to?(:then)
+  require "action_policy/ext/yield_self_then"
+  using ActionPolicy::Ext::YieldSelfThen
+end
+
+unless {}.respond_to?(:transform_keys)
+  require "action_policy/ext/hash_transform_keys"
+  using ActionPolicy::Ext::HashTransformKeys
+end
 
 module ActionPolicy
   module Policy

lib/action_policy/utils/pretty_print.rb

@@ -9,8 +9,10 @@
 end
 
 module ActionPolicy
-  require "action_policy/ext/yield_self_then"
-  using ActionPolicy::Ext::YieldSelfThen
+  unless "".respond_to?(:then)
+    require "action_policy/ext/yield_self_then"
+    using ActionPolicy::Ext::YieldSelfThen
+  end
 
   # Takes the object and a method name,
   # and returns the "annotated" source code for the method: