FILE returns different value when using binding.pry

Question

__FILE__ returns the path of the current Ruby script file.

One potentially significant problem is that, if using binding.pry, __FILE__ evaluates to (pry). It is potentially problematic to have __FILE__ evaluate to different values depending on whether it is evaluated in the context of binding.pry. For example,

$stdout.print "****************************************\n\n"
$stdout.print "FILE: #{__FILE__}\n\n"
$stdout.print "****************************************\n\n"

binding.pry

When the script pauses at binding.pry, I get:

__FILE__
# >> (pry)

Does anyone know any mechanism to get the path of the current file even in the context of binding.pry?

Assign it before stopping. current_file = __FILE__; binding.pry — Sergio Tulentsev
– Sergio Tulentsev, Commented Dec 13, 2018 at 23:53
FYI you don't need to use pry since Ruby 2.4: binding.irb is built-in and largely equivalent. — Max
– Max, Commented Dec 14, 2018 at 15:33
@anothermh yep, my comment is totally unrelated to the question. Just pointing out that pry is no longer necessary — Max
– Max, Commented Dec 14, 2018 at 16:56

anothermh · Accepted Answer · 2018-12-14 00:55:17Z

2

Use _file_ instead of __FILE__. For example, given two files:

# foo.rb
require 'pry'
require './bar'
binding.pry
b = Bar.new

and:

# bar.rb
require 'pry'
class Bar
  def initialize
    binding.pry
  end
end

Run them with ruby foo.rb:

ruby foo.rb

From: /Users/username/foo.rb @ line 3 :

    1:     require 'pry'
    2:     require './bar'
 => 3:     binding.pry
    4:     b = Bar.new

(main):1 ⇒ _file_
=> "/Users/username/foo.rb"
(main):2 ⇒ exit

From: /Users/username/bar.rb @ line 4 Bar#initialize:

    3: def initialize
 => 4:   binding.pry
    5: end

(#<Bar:0x00007fbb6caaff08>):1 ⇒ _file_
=> "/Users/username/bar.rb"

_file_ and any other local variable names can be found in binding.local_variables.

answered Dec 14, 2018 at 0:55

anothermh

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anothermh · Accepted Answer · 2018-12-14 19:11:27Z

1

Sergio Tulentsev made a simple suggestion, assign __FILE__ to a variable before invoking binding.pry.

anothermh, mentioned _file_ which is available in binding pry.

In the end, I combined the two answers:

# When in the context of binding.pry, __FILE__ resolves to '(pry)',
# binding contains the local variable _file_ which always resolves to
# the current file, even when being evaluated in the context of binding.pry .
# _file_ is only available, in binding. This does the trick:

current_file = __FILE__.downcase == '(pry)' ? _file_ : __FILE__

edited Dec 14, 2018 at 19:11

anothermh

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answered Dec 14, 2018 at 15:32

Peter Jirak Eldritch

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1 Comment

anothermh Over a year ago

Beware that _file_ returns the absolute path while __FILE__ does not, so do not expect them to be perfectly interchangeable if you're subsequently parsing the value of current_file. I don't see any reason not to continue using just __FILE__, since the only time I can see _file_ being necessary is when manually typing into the REPL.

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