Shell#ask: support a noecho option for stdin

[vanm]

Support using "ask" without echoing back stdin for passwords and other sensitive information.

Relies on io/console and http://apidock.com/ruby/IO/noecho (not supported in 1.8.7 or 1.9.2 unfortunately)

[coveralls]

Coverage remained the same when pulling eb3ceb2 on socialcast:stdin-noecho-support into 8a09e6b on wycats:master.

[coveralls]

Coverage remained the same when pulling eb3ceb2 on socialcast:stdin-noecho-support into 8a09e6b on wycats:master.

[sferik]

As proposed in #209, I’d prefer if the option was named echo: false instead of noecho. Overall, I'm 👍 on this feature.

[coveralls]

Coverage remained the same when pulling dbfdd30 on socialcast:stdin-noecho-support into 8a09e6b on wycats:master.

[vanm]

@sferik Thanks for the feedback. I updated the option to be :echo => false. Just a reminder that this is only compatible with 1.9.3+ (I see your Travis build is set up to run specs against 1.8.7 and 1.9.2).

[eventualbuddha]

Just noticed a bit too late what you said about this being 1.9.3+ only. We could polyfill $stdin.noecho using the usual technique before that method was available. @vanm, what do you think?

[vanm]

A few options come to mind:

1. Revert and wait until thor drops support for <1.9.3
2. Implement our own cross-platform solution like Add password prompt through shell.ask("Pass: ", :password => true) #209 (polyfill in case <1.9.3 and use stdin.noecho when available)
3. Make this :echo option dependent on Ruby version. Not a great UX to have varying functionality based on Ruby version, but an option.

Any maintainers have a preference? I just proposed this as a 1.9.3-ready option to solve the problem, but understand the library needs to be compatible with 1.8.7 and 1.9.2.

[TimMoore]

It would be great to restore 1.8.7 compatibility. This is preventing Bundler from updating to a newer version of Thor (rubygems/bundler#2736). We'd like to get the fix for #362.

[TimMoore]

Looks like this was covered in #380.