Shared clone from worktree directory

Hi,

For better, or worse, I encountered a script doing a git clone --shared from the working directory. However, if clone --shared is run from a worktree, it fails with cryptic errors.

Ex: elmarco@boraha:/tmp/test/wt (wt)$ git worktree list /tmp/test 4ae16a0 [master] /tmp/test/wt 4ae16a0 [wt] elmarco@boraha:/tmp/test/wt (wt)$ git clone --shared . clone-dir Cloning into 'clone-dir'... done. error: object directory /tmp/test/.git/worktrees/wt/objects does not exist; check .git/objects/info/alternates. fatal: update_ref failed for ref 'HEAD': cannot update ref 'refs/heads/wt': trying to write ref 'refs/heads/wt' with nonexistent object 4ae16a066ee088d40dbefeaaae7b5578d68b4b51 fatal: The remote end hung up unexpectedly

Is this a bug? If not, a nicer error message would be welcome, as well as man page note.

thanks