From de1fbd182e265da9ef5893d8de50afbdadb99c7a Mon Sep 17 00:00:00 2001
From: Jean Boussier <jean.boussier@gmail.com>
Date: Mon, 24 Nov 2025 08:48:19 +0100
Subject: [PATCH] Simpler and faster check for the delegation fastpath

Fix: https://github.com/ruby/forwardable/issues/35
[Bug #21708]

Trying to compile code to check if a method can use the delegation
fastpath is a bit wasteful and cause `RUPYOPT=-d` to be full of
misleading errors.

It's simpler and faster to use a simple regexp to do the same check.
---
 forwardable.gemspec     |  2 +-
 lib/forwardable.rb      | 34 ++++++++++++++--------------------
 lib/forwardable/impl.rb | 17 -----------------
 3 files changed, 15 insertions(+), 38 deletions(-)
 delete mode 100644 lib/forwardable/impl.rb

diff --git a/forwardable.gemspec b/forwardable.gemspec
index 9ad59c5..1b539bc 100644
--- a/forwardable.gemspec
+++ b/forwardable.gemspec
@@ -19,7 +19,7 @@ Gem::Specification.new do |spec|
   spec.licenses      = ["Ruby", "BSD-2-Clause"]
 
   spec.required_ruby_version = '>= 2.4.0'
-  spec.files         = ["forwardable.gemspec", "lib/forwardable.rb", "lib/forwardable/impl.rb"]
+  spec.files         = ["forwardable.gemspec", "lib/forwardable.rb"]
   spec.bindir        = "exe"
   spec.executables   = []
   spec.require_paths = ["lib"]
diff --git a/lib/forwardable.rb b/lib/forwardable.rb
index 76267c2..040f467 100644
--- a/lib/forwardable.rb
+++ b/lib/forwardable.rb
@@ -109,8 +109,6 @@
 # +delegate.rb+.
 #
 module Forwardable
-  require 'forwardable/impl'
-
   # Version of +forwardable.rb+
   VERSION = "1.3.3"
   VERSION.freeze
@@ -206,37 +204,33 @@ def self._delegator_method(obj, accessor, method, ali)
     if Module === obj ?
          obj.method_defined?(accessor) || obj.private_method_defined?(accessor) :
          obj.respond_to?(accessor, true)
-      accessor = "#{accessor}()"
+      accessor = "(#{accessor}())"
     end
 
     args = RUBY_VERSION >= '2.7' ? '...' : '*args, &block'
     method_call = ".__send__(:#{method}, #{args})"
-    if _valid_method?(method)
+    if method.match?(/\A[_a-zA-Z]\w*[?!]?\z/)
       loc, = caller_locations(2,1)
       pre = "_ ="
       mesg = "#{Module === obj ? obj : obj.class}\##{ali} at #{loc.path}:#{loc.lineno} forwarding to private method "
-      method_call = "#{<<-"begin;"}\n#{<<-"end;".chomp}"
-        begin;
-          unless defined? _.#{method}
-            ::Kernel.warn #{mesg.dump}"\#{_.class}"'##{method}', uplevel: 1
-            _#{method_call}
-          else
-            _.#{method}(#{args})
-          end
-        end;
+      method_call = <<~RUBY.chomp
+        if defined?(_.#{method})
+          _.#{method}(#{args})
+        else
+          ::Kernel.warn #{mesg.dump}"\#{_.class}"'##{method}', uplevel: 1
+          _#{method_call}
+        end
+      RUBY
     end
 
-    _compile_method("#{<<-"begin;"}\n#{<<-"end;"}", __FILE__, __LINE__+1)
-    begin;
+    eval(<<~RUBY, nil, __FILE__, __LINE__ + 1)
       proc do
         def #{ali}(#{args})
-          #{pre}
-          begin
-            #{accessor}
-          end#{method_call}
+          #{pre}#{accessor}
+          #{method_call}
         end
       end
-    end;
+    RUBY
   end
 end
 
diff --git a/lib/forwardable/impl.rb b/lib/forwardable/impl.rb
deleted file mode 100644
index 0322c13..0000000
--- a/lib/forwardable/impl.rb
+++ /dev/null
@@ -1,17 +0,0 @@
-module Forwardable
-  # :stopdoc:
-
-  def self._valid_method?(method)
-    catch {|tag|
-      eval("BEGIN{throw tag}; ().#{method}", binding, __FILE__, __LINE__)
-    }
-  rescue SyntaxError
-    false
-  else
-    true
-  end
-
-  def self._compile_method(src, file, line)
-    eval(src, nil, file, line)
-  end
-end