Executive summary: In order to use git in Cygwin with Smart HTTP style URLs, you need to also install the libsasl2 and ca-certificates packages.

I recently set up a new Cygwin environment to test and document the process of cloning and using one of the OpenXC repositories from GitHub in Windows, since this is a very popular platform for many users. Unfortunately many people were being blocked at the very first step, just attempting to clone the repository.

GitHub transitioned a little while back to using Smart HTTP by default for all public repositories. This is great because even for folks that need to commit to repositories, they can skip the SSH key dance if they aren’t already using that in their daily routine. This seems to be especially the case for Windows users.

So for OpenXC, a new users installs Cygwin with the “git” package and attempts to clone the repository, and it explodes:

$ git clone https://github.com/openxc/openxc-android
Cloning into 'openxc-android'...
/usr/lib/git-core/git-remote-https.exe: error while loading shared
    libraries: ?: cannot open shared object file: No such file or directory

I was able to figure out which library was missing by using cygcheck:

$ cygcheck /usr/lib/git-core/git-remote-https.exe
C:\cygwin\lib\git-core\git-remote-https.exe
  C:\cygwin\bin\cygcrypto-0.9.8.dll
    C:\cygwin\bin\cygwin1.dll
      C:\Windows\system32\KERNEL32.dll
        C:\Windows\system32\API-MS-Win-Core-RtlSupport-L1-1-0.dll
        C:\Windows\system32\ntdll.dll

    ... <snip> ...

    C:\cygwin\bin\cyglber-2-4-2.dll
    C:\cygwin\bin\cygldap-2-4-2.dll
      C:\cygwin\bin\cygssl-1.0.0.dll
    C:\cygwin\bin\cygssh2-1.dll
cygcheck: track_down: could not find cygsasl2-2.dll

This tells me that libsasl2 is missing, so install that from the Cygwin package manager.

Try the clone again and it still fails:

$ git clone https://github.com/openxc/openxc-android.git
Cloning into 'openxc-android'...
error: error setting certificate verify locations:
  CAfile: /usr/ssl/certs/ca-bundle.crt
  CApath: none while accessing
        https://github.com/openxc/openxc-android.git/info/refs
fatal: HTTP request failed

By default, Cygwin doesn’t have the CA root certificates installed, so nothing using SSL will work properly. Install the ca-certificates package to install those.

Finally, success:

$ git clone https://github.com/openxc/openxc-android
Cloning into 'openxc-android'...
remote: Counting objects: 13997, done.
remote: Compressing objects: 100% (2759/2759), done.
remote: Total 13997 (delta 7568), reused 13989 (delta 7560)
Receiving objects: 100% (13997/13997), 9.30 MiB | 1.04 MiB/s, done.
Resolving deltas: 100% (7568/7568), done.

This problem was a little difficult to debug because I don’t think very many people encounter it. Typically when someone installs Cygwin, they also install a base set of packages that includes things like curl. Well, one of the curl package’s many dependencies are both libsasl2 and ca-certificates, which explains why many people do not encounter this problem.