Git error on `whippet generate app`

[RobjS]

whippet generate app -d Projects/test
Creating a new whippet application in Projects/test
Downloading and unzipping template file
fatal: ambiguous argument 'HEAD': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'
Checkout failed:

HEADNew whippet app successfully generated at Projects/test

[RobjS]

A git bisect says this error was introduced in 732e8f576e683e4c64495a0ef10fcd0dd85b43a8: 732e8f5

It looks like if (!$target_repo->current_commit()) { isn't returning false, but instead just outputting an error.

[snim2]

So, the output above ends with New whippet app successfully generated at Projects/test. When I try to reproduce, the error message appears but the app is generated correctly.

Is the request here to suppress the error message?