Updated: Ruby: Debugging a method's source location and code

Changes

+## Access the `Method` object
Dead simple: Get the method object and ask for its owner:
-"foo".method(:upcase)
- => #<Method: String#upcase> 
-"foo".method(:upcase).owner
- => String
+```rb
+"foo".method(:upcase)
+# => #<Method: String#upcase> 
+
+"foo".method(:upcase).owner
+# => String
+```
+
+## Look up a method's source location
+
Ruby 1.9 adds a method `Method#source_location` that returns file and line number where that method is defined.
-class Example; def method() end end
- => nil
-Example.new.method(:method).source_location
- => ["(irb)", 11] 
-
-"foo".method(:upcase).source_location
- => nil # String#upcase is a native method that's defined in C
-
-Rumor has it in Ruby 1.8 there is a gem `ruby18_source_location` that does something similar.
+```rb
+class Example; def method() end; end
+# => nil
+
+Example.new.method(:method).source_location
+# => ["(irb)", 11] 
+
+"foo".method(:upcase).source_location
+# => nil # String#upcase is a native method that's defined in C
+```
+
+## Look up a method's source code
+
+If your Gemfile comes with [method_source](https://rubygems.org/gems/method_source) (a dependency of Rails 7+), you can can use inspect the source code directly using the `Method#source` method:
+
+```rb
+puts User.new.method(:name).source
+
+# =>
+# def name
+#   "#{first_name} #{last_name}".strip
+# end
+```
---
## Also see 
+ [Using Ruby's Method objects for inspecting methods](https://makandracards.com/makandra/610159-using-the-ruby-s-class-method-for-inspecting-and-debugging-methods)
+ [How to examine an unknown Ruby object](https://makandracards.com/makandra/55983-how-to-examine-an-unknown-ruby-object)