Commas in directory names causes hang in ActiveSupport::FileUpdateChecker

[JonRowe]

Having commas in directory names passed through to ActiveSupport::FileUpdateChecker causes an infinite hang whilst Dir[@glob] tries and fails to list files in these directories. This wasn't an issue before ~> 3.2 but on 3.2 upwards it prevents Rails from booting in development mode and prevents test suites running (rspec, cucumber at least).

Commas are perfectly valid parts of directory names (on OS X at least) and escaping them when compiling the glob solves this issue.

This issue can be triggered by adding such directories to the autoload component of rails config see: https://github.com/JonRowe/rails-broken-dir-example for an example broken application.

This is a duplicate of #5445 but, as requested, against master and without fork.

Be warned on OSX/MRI Ruby this causes an infinite hang on test failure...

[josevalim]

Be warned on OSX/MRI Ruby this causes an infinite hang on test failure...

Thanks. But I am a bit confused. This patch will cause an infinite hang even with the bug fixed? o.O

[JonRowe]

No only if the test fails

[josevalim]

Which hopefully will rarely happen, confirm/deny? Also, shouldn't the timeout catch the hanging?

[JonRowe]

Shouldn't happen as long as comma's are escaped. So confirm.

Timeout seems to use thread, but neither thread nor timeout catch the hanging on MRI ruby. It seems Dir.glob goes straight into C and blocks somewhere low down in Ruby, beyond the reach of the thread scheduler / GIL

My theory is that without escaping you are essentially globing the entirety of the filesystem, if you leave an unpatched version going long enough on OS X you get access denied errors for various private system directories bubbling up.

[josevalim]

Awesome, thanks for the explanation and the fixes.

[JonRowe]

Thanks :)

[JonRowe]

For the benefit of anybody else running into this, it can also be triggered purely by having directories with comma's in the name in your app folder.