git commands don't work without cached credentials

[aryairani]

We currently use System.Process.readProcess and System.Process.readProcessWithExitCode, which pass canned stdin to git. When git wants input from the user (e.g. ssh public key passphrase or https credentials), it fails, resulting in an error like:

I couldn't find the ref v2 in the repository at [email protected]:unisonweb/base ;

or

I couldn't find the ref main in the repository at [email protected]:unisonweb/base ;

The workaround is to set up your environment so that git doesn't ask for credentials, e.g. using ssh-agent to cache your passphrase. If ssh-agent doesn't work for you (it didn't for me in windows (#598)), then you have to not have a passphrase. 😬

A fix would be similar to whatever git is doing to pass input through to ssh. Maybe some CreateProcess](https://hackage.haskell.org/package/process-1.6.9.0/docs/System-Process.html) settings?

[aryairani]

Another possible, better workaround for Windows is that there seems to be some sort of Microsoft gui authentication helper for signing into Github via https without stdin. I haven't tried testing this; it's just something that showed up for me when I was trying to accomplish something else.