Can't install any apps using cask on OS X Yosemite

[dsw88]

I just installed homebrew and cask on what is a relatively clean system (just installing stuff for the first time today). Everything appeared to install correctly and "brew cask doctor" didn't tell me about any issues that need to be fixed.

However, whenever I try to install any cask apps I get the following error:

brew cask install google-chrome
==> Caveats
The Mac App Store version of 1Password won't work with a Homebrew-Cask-linked Google Chrome. To bypass this limitation, you need to either:

  + Move Google Chrome to your /Applications directory (the app itself, not a symlink).
  + Install 1Password from outside the Mac App Store (licenses should transfer automatically, but you should contact AgileBits about it).

==> Downloading https://dl.google.com/chrome/mac/stable/GGRO/googlechrome.dmg
Already downloaded: /Library/Caches/Homebrew/google-chrome-latest.dmg
Error: undefined method `extname' for nil:NilClass
Please report this bug:
    https://github.com/caskroom/homebrew-cask/issues
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/container/criteria.rb:43:in `extension'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/container/pkg.rb:3:in `me?'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/container.rb:50:in `block in for_path'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/container.rb:48:in `each'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/container.rb:48:in `find'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/container.rb:48:in `for_path'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/installer.rb:85:in `extract_primary_container'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/installer.rb:52:in `install'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli/install.rb:20:in `block in install_casks'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli/install.rb:17:in `each'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli/install.rb:17:in `install_casks'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli/install.rb:6:in `run'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli.rb:81:in `run_command'
/usr/local/Cellar/brew-cask/0.49.0/rubylib/cask/cli.rb:121:in `process'
/usr/local/bin/brew-cask.rb:42:in `<top (required)>'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/usr/local/Library/brew.rb:59:in `require?'
/usr/local/Library/brew.rb:142:in `<main>'

I'm on version 10.10.1 of OS X, using Ruby 2.0.0p481. Any clue as to what's causing this error?

[denis]

The same problem for Mavericks.

[rolandwalker]

Hi!

This is a duplicate of #7946.

Thanks to an analysis by @renard, we just merged a fix and cut release v0.50.0. The following command should fix the issue:

$ brew update && brew upgrade brew-cask && brew cleanup && brew cask cleanup

[ghost]

Oh, thanks. This upgrade really solved troubles with packages installing.

[trungie]

This worked for me

➜  ~  brew search brew-cask        
No formula found for "brew-cask".
Searching pull requests...
➜  ~  brew upgrade caskroom/cask/brew-cask
==> Upgrading 1 outdated package, with result:
brew-cask 0.51.1
==> Upgrading brew-cask
==> Cloning https://github.com/caskroom/homebrew-cask.git
Updating /Library/Caches/Homebrew/brew-cask--git
==> Checking out tag v0.51.1
🍺  /usr/local/Cellar/brew-cask/0.51.1: 2374 files, 9.5M, built in 31 seconds
➜