Empty directory treated as git repo

[eschnett]

I am using BinaryBuilder on a Linux system with an unstable network. Often, connecting to a remote system fails.

I see this error there:

$ julia +1.7 build_tarballs.jl --debug --verbose riscv64-linux-gnu
[ Info: Building for riscv64-linux-gnu
┌ Info: Using cached git repository
│   url = "https://github.com/Cyan4973/xxHash.git"
└   repo_path = "/home/eschnett/.julia/dev/BinaryBuilderBase/deps/downloads/clones/xxHash.git-3a9de2a65113f489177f560d4fe4b80b50b4782b0a0d98809fd253cf8ecfdcfb"
ERROR: LoadError: GitError(Code:ENOTFOUND, Class:Repository, could not find repository from '/home/eschnett/.julia/dev/BinaryBuilderBase/deps/downloads/clones/xxHash.git-3a9de2a65113f489177f560d4fe4b80b50b4782b0a0d98809fd253cf8ecfdcfb')

I find that the directory in question (repo_path) does exist but is empty. I think BinaryBuilder is getting confused, seeing the directory and assuming that it contains the git repo, when in reality the previous clone failed.