Re: `git mv` has ambiguous error message for non-existing target

Patrick Lehner [off-list ref] writes:

To reproduce:
- cd into a git repo
- assuming "filea.txt" is an existing file in the CWD, and "dirb" is
neither a file nor a directory in the CWD, use the command "git mv
filea.txt dirb/filea.txt"
- this will produce an error message like `fatal: renaming 'filea.sh'
failed: No such file or directory`

It does not mention that the problem is, in fact, the target directory
not existing. This seems to be mostly a problem for users unfamiliar
with bash/*nix console commands. Although it is documented that git mv
will not create intermediate folders (which is fine, because neither
does mv), the error message might lead to believe a problem exists
with the source file.

    $ rm -fr xxx
    $ >yyy
    $ mv yyy xxx/yyy
    mv: cannot move `yyy' to `xxx/yyy': No such file or directory

It doesn't mention that the problem is with 'xxx' and not 'yyy'
either.