Jenkins creates directories with invalid names.

This results in git checkouts HANGING on the slave machine.

It intentionally truncates directory names for workspaces, to avoid problems on systems like Windows.

That truncation can lead to directories beginning with invalid characters like -.

This makes it impossible to delete those directories from the command line.

Removal requires using Screen Sharing.app to launch Finder.app to remove the workspace directories from SSH slaves.

Please add a single [a-zA-Z] character at the beginning of any truncated name which doesn't start with a character in that set.

See also JENKINS-46493, JENKINS-54869, JENKINS-54640.