Cygwin programs can handle Unix form paths: $ ls /var cache lib log run tmp and also Windows form paths: $ ls 'C:\cygwin64\var' cache lib log run tmp However current Cygwin Git cannot: $ git clone git://github.com/benhoyt/goawk 'C:\cygwin64\tmp\goawk' Cloning into 'C:\cygwin64\tmp\goawk'... fatal: Invalid path '/home/Steven/C:\cygwin64\tmp\goawk': No such file or directory It seems the problem is that Git thinks the Windows form path is relative because it does not start with "/". A Git Bisect reveals this: 05b458c104708141d2fad211d79703b3b99cc5a8 is the first bad commit commit 05b458c104708141d2fad211d79703b3b99cc5a8 Author: Brandon Williams <bmwill@xxxxxxxxxx> Date: Mon Dec 12 10:16:52 2016 -0800 real_path: resolve symlinks by hand The current implementation of real_path uses chdir() in order to resolve symlinks. Unfortunately this isn't thread-safe as chdir() affects a process as a whole and not just an individual thread. Instead perform the symlink resolution by hand so that the calls to chdir() can be removed, making real_path one step closer to being reentrant. Signed-off-by: Brandon Williams <bmwill@xxxxxxxxxx> Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx> This causes problems for any non-Cygwin tools that might call Git: http://github.com/golang/go/issues/23155
