rsync on windows fails

[osroot25]

I think, hashicorp/vagrant#4073 (and in some way hashicorp/vagrant#3230 ) originates in a problem found here, regarding the environment variable VAGRANT_DETECTED_OS

the Vagrant/bin/vagrant bash-file sets this variable, but the Vagrant/bin/vagrant.exe does not, at least from what I can see and on the windows 7/8 systems I can access.

If I am correct, https://github.com/mitchellh/vagrant-installers/blob/master/substrate/launcher/main.go is the (only/main?) source code for the vagrant.exe, isn't it?
It doesn't set the above variable, hence the actual vagrant process can't decide if cygwin is used or not / assumes not.

Question is, how can one check there in Go, whether cygwin is installed or not? Is it practicable to match the windows PATH variable, if the cygwin-bin dir is included?

[osroot25]

@mitchellh have you already seen this?

[huangsam]

@osroot25 If the cygwin-bin dir is included into the PATH variable, Cygwin utilities like cygpath can be queried for. Getting the result from which cygpath can determine whether Cygwin exists or not. I think that using the os/exec package is a good starting point.