fatal output from git-show really wants a terminal

It appears that when outputting a fatal error, git-show will choose stdout over stderr if stdout is a terminal and stderr is not. How do I redirect the error but still allow stdout to be displayed?

~/git$ mkdir test

~/git$ cd test

~/git/test$ git init

~/git/test$ git show 12345

fatal: ambiguous argument '12345': unknown revision or path not in the working tree. Use '--' to separate paths from revisions

~/git/test$ git show 12345 2> /dev/null

fatal: ambiguous argument '12345': unknown revision or path not in the working tree. Use '--' to separate paths from revisions

~/git/test$ git show 12345 > /dev/null

fatal: ambiguous argument '12345': unknown revision or path not in the working tree. Use '--' to separate paths from revisions

~/git/test$ git show 12345 > /dev/null 2> /dev/null

~/git/test$ git show 12345 > /tmp/out 2> /tmp/err

~/git/test$ cat /tmp/out

~/git/test$ cat /tmp/err

fatal: ambiguous argument '12345': unknown revision or path not in the working tree. Use '--' to separate paths from revisions