Unexpected behavior of CGI#unescape when required via aws-sdk

[bankair]

Hi Folks,

I'm currently using aws-sdk 2.9.11, and it seems to have a bad side effect on the behavior of CGI#unescape.

Ruby version: mri 2.4.1

Gemfile:

source 'https://rubygems.org'
gem 'aws-sdk', '~> 2'

Test file:

require 'aws-sdk'
# The next line should print 'foo bar'
puts CGI.unescape('foo%20bar')

What I expected: an output line showing 'foo bar'.

What I got:
the following exception:

test.rb:3:in `unescape': uninitialized class variable @@accept_charset in #<Class:CGI> (NameError)
Did you mean?  @@accept_charset
	from test.rb:3:in `<main>'

An easy workaround is adding an explicit require "CGI" before (or after) the aws sdk require:

require 'CGI'
require 'aws-sdk'
# The next line prints 'foo bar'
puts CGI.unescape('foo%20bar')

[awood45]

This definitely looks like a side effect of #1487 - and the best possible workaround seems to be what you've already discovered, to require the rest of the cgi library as needed.

However the exception is very unhelpful...considering if we should return the old require pattern.

[bankair]

Yep, I agree on the usefulness of the exception 😄

[cjyclaire]

Adding info.

Looks like this is another problem with Ruby 2.4, I can reproduce the same error there. For Ruby 2.3, it works fine though. Definitely an issue that we will follow up with.

[awood45]

Okay, given that this seems to be a Ruby 2.4 change in cgi, it's probably easiest to just patch that now be reverting to the full CGI import now, and figure out what they changed later.

[awood45]

On second thought, the bug label is inappropriate given that the weirdness seems to center on Ruby proper (consider opening an issue with them), but I'll change the import strategy regardless.

[awood45]

I've pushed a fix to this that will go out with the next release.