pry/pry · error · CommandError

Could not find original `def #{method.original_name}` line t

Error message

Could not find original `def #{method.original_name}` line to patch.

What it means

`edit-method` re-defines a method by rewriting its source in the owner's context. To do that, Pry::Method::Patcher must match the original definition line against `def [<receiver>.]<original_name>` and rewrite it. When the first source line doesn't literally match that pattern — define_method bodies, aliases where original_name differs from the visible def, shifted source_location — CommandError is raised and no patch is applied.

Source

Thrown at lib/pry/method/patcher.rb:82

      end

      # Update the definition line so that it can be eval'd directly on the Method's
      # owner instead of from the original context.
      #
      # In particular this takes `def self.foo` and turns it into `def foo` so that we
      # don't end up creating the method on the singleton class of the singleton class
      # by accident.
      #
      # This is necessarily done by String manipulation because we can't find out what
      # syntax is needed for the argument list by ruby-level introspection.
      #
      # @param [String] line The original definition line. e.g. def self.foo(bar, baz=1)
      # @return [String]  The new definition line. e.g. def foo(bar, baz=1)
      def definition_for_owner(line)
        if line =~ /\Adef (?:.*?\.)?#{Regexp.escape(method.original_name)}(?=[\(\s;]|$)/
          "def #{method.original_name}#{$'}"
        else
          raise CommandError,
                "Could not find original `def #{method.original_name}` line " \
                "to patch."
        end
      end

      # Apply wrap_for_owner and wrap_for_nesting successively to `source`
      # @param [String] source
      # @return [String] The wrapped source.
      def wrap(source)
        wrap_for_nesting(wrap_for_owner(source))
      end

      # Update the source code so that when it has the right owner when eval'd.
      #
      # This (combined with definition_for_owner) is backup for the case that
      # wrap_for_nesting fails, to ensure that the method will still be defined in
      # the correct place.
      #

View on GitHub (pinned to 1356402628)

Solutions

1. Edit the defining file directly: find it with `Foo.instance_method(:price).source_location`, then `edit lib/widget.rb:42`.
2. For define_method-created methods, edit the code that generates them, not the method object.
3. Re-define manually in the pry buffer instead of using edit-method when the def line is synthetic.

Example fix

# before
pry> edit-method Widget#price
# CommandError: Could not find original `def price` line to patch.

# after
pry> Widget.instance_method(:price).source_location # => ['lib/widget.rb', 42]
pry> edit lib/widget.rb:42

line = Foo.instance_method(:price).source_location
# definition_for_owner needs a literal 'def price' first line; check before patching
patchable = line && File.readlines(line[0])[line[1] - 1] =~ /\Adef (?:.*\.)?price\b/

begin
  Pry::Method::Patcher.new(method_obj).patch
rescue Pry::CommandError => e
  loc = method_obj.source_location
  edit(loc.join(':')) if loc # manual fallback
end

When it happens

Trigger: `edit-method` on a method created by `define_method(:price) { ... }`; on an aliased method whose original_name points at a different def line; on methods whose source_location line moved because the file was edited after loading.

Common situations: DSL-heavy codebases built on define_method; alias_method wrappers (common in ActiveRecord and decorator gems); hot-reloaded code with stale locations.

Related errors

• Exception has no associated file.
• Cannot edit exceptions raised in REPL.
• No help found for '#{args.first}'
• Must provide a file name.
• Replay index #{index} points out to another replay call: `#{

AI-assisted analysis of pry/pry@1356402628 (2026-08-21). Data as JSON: /api/errors/8a07eff11c132754. Report an issue: GitHub.