jashkenas/coffeescript — pull request #3592 by mmotorny (2014-08-18 03:54:56+00:00)
Title: Exit with an error code 1 if could not write a compiled JavaScript file ...

...or a source map.

Currently CoffeeScript reports a success even if it failed to write a
compiled file to disk. This behavior confuses automated tools such as
test runners which may return false positives if a test failed to
compile because of a file lock.