Allow rake release to ask for input (3rd take)

[deivid-rodriguez]

This PR supersedes #7108 and #7005.

It fixes #6854.

What was the end-user problem that led to this PR?

The problem was that if users has 2FA authentication on their rubygems account, rake release doesn't really work at the moment, since it hangs asking for the OTP code, but without letting the user know.

What was your diagnosis of the problem?

My diagnosis was that we need to allow the rake release helper that shells out to gem push to read gem push output and show it to the user, so that she can introduce the requested information.

What is your fix for the problem, implemented in this PR?

My fix is inspired by @segiddins's comment in #6854 (comment). Kernel#system works like we would expect in this situation.

Why did you choose this fix out of the possible options?

I chose this fix because #7108 had a few problems:

• It would update the sh helper, which is used in many different places. This was unnecessary since most of the times we shell out to the gem CLI we don't need to ask for input, and it also produced a very verbose output in those cases, since everything the gem CLI prints to the screen would be printed by the bundler helpers too. This PR does not change the current output, other than for rake release.

• It would print duplicate output. This is a rake release test using Fix GemHelper to allow reading Input/Output #7108:

  $ RUBYOPT="-I../bundler/lib" ../bundler/exe/bundle exec rake release
    Successfully built RubyGem
    Name: rake_release_tester
    Version: 0.1.0
    File: rake_release_tester-0.1.0.gem
  rake_release_tester 0.1.0 built to pkg/rake_release_tester-0.1.0.gem.
  v0.1.0
  Tag v0.1.0 has already been created.
  Pushing gem to https://rubygems.org...
  You have enabled multi-factor authentication. Please enter OTP code.
  Code:   asd
  Your OTP code is incorrect. Please check it and retry.
  rake aborted!
  Pushing gem to https://rubygems.org...
  You have enabled multi-factor authentication. Please enter OTP code.
  Code:   Your OTP code is incorrect. Please check it and retry.
  /home/deivid/Code/bundler/lib/bundler/gem_helper.rb:187:in `sh'
  /home/deivid/Code/bundler/lib/bundler/gem_helper.rb:109:in `rubygem_push'
  /home/deivid/Code/bundler/lib/bundler/gem_helper.rb:70:in `block in install'
  /home/deivid/Code/bundler/lib/bundler/cli/exec.rb:69:in `load'
  /home/deivid/Code/bundler/lib/bundler/cli/exec.rb:69:in `kernel_load'
  /home/deivid/Code/bundler/lib/bundler/cli/exec.rb:28:in `run'
  /home/deivid/Code/bundler/lib/bundler/cli.rb:468:in `exec'
  /home/deivid/Code/bundler/lib/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
  /home/deivid/Code/bundler/lib/bundler/vendor/thor/lib/thor/invocation.rb:126:in `invoke_command'
  /home/deivid/Code/bundler/lib/bundler/vendor/thor/lib/thor.rb:387:in `dispatch'
  /home/deivid/Code/bundler/lib/bundler/cli.rb:26:in `dispatch'
  /home/deivid/Code/bundler/lib/bundler/vendor/thor/lib/thor/base.rb:466:in `start'
  /home/deivid/Code/bundler/lib/bundler/cli.rb:17:in `start'
  ../bundler/exe/bundle:30:in `block in <main>'
  /home/deivid/Code/bundler/lib/bundler/friendly_errors.rb:123:in `with_friendly_errors'
  ../bundler/exe/bundle:22:in `<main>'
  Tasks: TOP => release => release:rubygem_push
  (See full trace by running task with --trace)
  

  This is the same test using this PR:

  $ RUBYOPT="-I../bundler/lib" ../bundler/exe/bundle exec rake release
  rake_release_tester 0.1.0 built to pkg/rake_release_tester-0.1.0.gem.
  Tag v0.1.0 has already been created.
  Pushing gem to https://rubygems.org...
  You have enabled multi-factor authentication. Please enter OTP code.
  Code:   asdfasdf
  Your OTP code is incorrect. Please check it and retry.
  

• Previous approach was hard to test. The test included here might not be great but it's something...

[colby-swandale]

@bundlerbot r+

[ghost]

Build succeeded

• continuous-integration/travis-ci/push

[ioquatix]

I recently tried this and it worked. There was one issue.

I had bundler 2.0.2 installed, but because of the Gemfile.lock it was still trying to use 1.17.something - deleting the Gemfile.lock fixed this issue and allowed me to use 2.0.2 which has the OTP support.

Great work sorting this out! Very useful.

[indirect]

@ioquatix fyi in the future, you can also run bundle update --bundler to keep your Gemfile but also use the latest bundler. We're hoping to not require a manual step in the future 👍