Re: [PATCH 1/2] cat-file doc: document that -e will return some output

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 10, 2018, 22:09 UTC
Message-ID: <xmqqk1wpz7qu.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <xmqqtvvtz95g.fsf@gitster.mtv.corp.google.com>

Junio C Hamano <gitster@pobox.com> writes:

Show 17 quoted lines

> Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:
>
>> 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, currently:
>>
>>     $ git cat-file -e malformed; echo $?
>>     fatal: Not a valid object name malformed
>>     128
>>
>> A careful reader of this documentation would be mislead into thinking
>> the could write:
>>
>>     if ! git cat-file -e "$object" [...]
>
> It is arguable if such a reader is careful or careless.  I'd rather drop
> s/careful // there ;-)

Actually the phrasing around here was a bit strange, and I ended up rewriting a bit more.

    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>