From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: Derrick Stolee <stolee@gmail.com>, git@vger.kernel.org
Subject: Re: [PATCH] xrealloc: do not reuse pointer freed by zero-length realloc()
Date: Tue, 01 Sep 2020 08:58:54 -0700 [thread overview]
Message-ID: <xmqq3641ebep.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20200901135105.GA3284077@coredump.intra.peff.net> (Jeff King's message of "Tue, 1 Sep 2020 09:51:05 -0400")
Jeff King <peff@peff.net> writes:
> If we do handle it up-front, then I think we'd actually want:
>
> if (!size) {
> free(ptr);
> return xmalloc(0);
> }
>
> (i.e., to never return NULL for consistency with xmalloc() and
> xcalloc()).
Makes sense. I suspect that this is optimizing for a wrong case,
but in practice that should not matter. Not having to worry about
a request to resize to 0-byte in the remainder of the function is
actually a plus for readability, I would say.
>> > @@ -120,7 +120,7 @@ void *xrealloc(void *ptr, size_t size)
>> > memory_limit_check(size, 0);
>> > ret = realloc(ptr, size);
>> > if (!ret && !size)
>> > - ret = realloc(ptr, 1);
>> > + ret = realloc(ret, 1);
>>
>> I appreciate all the additional context for such a small change.
>
> Somebody's got to complete with you for ratio of commit message to diff
> lines. :)
>
> -Peff
next prev parent reply other threads:[~2020-09-01 16:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-01 11:18 [PATCH] xrealloc: do not reuse pointer freed by zero-length realloc() Jeff King
2020-09-01 13:04 ` Derrick Stolee
2020-09-01 13:51 ` Jeff King
2020-09-01 14:24 ` Derrick Stolee
2020-09-01 15:58 ` Junio C Hamano [this message]
2020-09-02 7:54 ` Jeff King
2020-09-02 19:19 ` Junio C Hamano
2020-09-03 3:50 ` Jonathan Nieder
2020-09-01 15:20 ` Andreas Schwab
2020-09-01 15:56 ` Junio C Hamano
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