From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 30 Jun 2015 19:23:08 GMT
Subject: Re: [PATCH 3/3] introduce "format" date-mode
Message-ID: <xmqqbnfxc86b.fsf@gitster.dls.corp.google.com>
In-Reply-To: <20150630175011.GA5349@peff.net>

Jeff King <peff@peff.net> writes:

> On Tue, Jun 30, 2015 at 09:22:18AM -0700, Junio C Hamano wrote:
>
>> Jeff King <peff@peff.net> writes:
>> 
>> >> 	strbuf_addf(&f, "%s ", fmt);
>> >
>> > Basically I was trying to avoid making any assumptions about exactly how
>> > strftime works. But presumably "stick a space in the format" is a
>> > universally reasonable thing to do. It's a hack, but it's contained to
>> > the function.
>> 
>> Why can't I shake this feeling that (" %s", fmt), i.e. prepend not
>> append, is the safer thing to do than to append?
>
> Because then removing the extra space involves `memmove` of the buffer,
> rather than just shortening the length by one.

That does not explain why I feel the other way is safer, though ;-)

In any case, responding myself to my other question, strftime(3)
does not define any useful error information even for a case where
you feed nonsense format to it, so it is even not possible to
protect ourselves by checking errno or doing something similar X-<.