environment variables & mks toolkit - patch opportunity?

M. Sebastian Comella sebastian@smashd.net
Wed Jul 25 22:44:00 GMT 2012

Hi all -
I recently lost a good chunk of my day tracking down a Cygwin issue
ultimately caused by an installation of IBM InfoSphere. The InfoSphere
installer surreptitiously installed MKS Toolkit, which in turn set a
bunch of environment variables that left Cygwin in a very unhelpful
state: attempting to start Cygwin via its usual mintty shortcut would
appear to hang, with mintty showing "sh.exe" in its title bar and
little else. The cause of the issue is unfortunately not very obvious
since there is no error message or other form of reporting. If I had
realized that MKS Toolkit was being installed I might have had a
fighting chance, but without that info I was in the dark.

Fortunately, fixing the issue is pretty easy and is a matter of
removing some Windows environment variables, as noted in this
2002-vintage thread:


My question is this: is there an opportunity to patch something in
Cygwin's startup "chain" to detect unsavory environment variables and
warn users in some fashion? I'm not sure what package (or core
process) could detect the situation and still get a warning off to the
user before everything goes fubar. Putting a check into the installer
may also be a viable solution, considering that the first thing I did
was run the Cygwin installer again to see if it could "repair" things.

I think I can take care of writing the patch, but I'd like some input
on where it even belongs before I give it a shot.



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