git isn’t optional. It’s used to install dependencies. In your case at least crystal-mysql requires git.
The error message unfortunately isn’t very helpful. The part about a “commit, branch or file” not existing is generic and doesn’t really match to the command being run (git tag --list).
Can you provide instructions on how to reproduce this behaviour? Probably the contents of shard.yml and the version of shards you’re using would help for that.
I need the version of the shards command, not the version of your shard. You can get that with shards --version.
It’s probably 0.17.0.
Maybe something is broken with the git repository. Try removing the .shards folder in your working directory. That should force shards to re-download everything.
I use VSCode and there I get a message:
The git repositories in the current folder are potentially unsafe as the folder are owned by someone other than the current user.