cat-file doc: document that -e will return some output
The -e option added in
7950571ad7 ("A few more options for
git-cat-file", 2005-12-03) has always errored out with message on
stderr saying that the provided object is malformed, like this:
$ git cat-file -e malformed; echo $?
fatal: Not a valid object name malformed
128
A reader of this documentation may be misled into thinking that
if ! git cat-file -e "$object" [...]
as opposed to:
if ! git cat-file -e "$object" 2>/dev/null [...]
is sufficient to implement a truly silent test that checks whether
some arbitrary $object string was both valid, and pointed to an
object that exists.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>