The issue here was that we had a PATH value in windows format and we're assuming it came from the shell environment and needed to be converted from POSIX to windows. The fix is to sniff to see if the path contains ';' and if so assume it's already in windows format and just return it as-is. The prior fix was to handle cygwin style POSIX path conversions, since we only handled mingw style POSIX paths.
The three important scenarios to test are (on Windows):
- Having cygwin installed and its bin dir on the PATH, with git installed
- Having RailsInstaller installed and the packaged git's bin dir on the PATH
- Using the pre-packaged msysgit we offer up (when we can't find git).
The issue should be exclusive to windows, so no need to test this scenario specifically on OS X or Linux (but confirm git still works as part of general acceptance tests)