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From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH v2] remote: plug memory leaks
Date: Sat, 25 Jul 2026 12:18:19 -0400	[thread overview]
Message-ID: <20260725161819.GA2343104@coredump.intra.peff.net> (raw)
In-Reply-To: <xmqqpl0b12gj.fsf@gitster.g>

On Sat, Jul 25, 2026 at 09:03:24AM -0700, Junio C Hamano wrote:

> * The initial iteration relied on the assumption that strings
>   borrowed from the configset subsystem will not go away, attempting
>   to plug the leak of 'instead_of[n].s' pointers without making
>   copies.  However, it turns out that all existing users other than
>   a select few make copies and do not rely on that assumption.  In
>   this version, I decided to simply follow suit, which might be
>   slightly inefficient but is vastly safer.

Heh, I was just in the middle of writing a message digging into this.

We should not rely on that assumption, because we sometimes discard the
configset (e.g., when discovering the repo, or when writing a new config
option). I couldn't come up with a case that fails, but I think it is
mostly luck (or lack of imagination) that there is no code path that
invalidates the configset between when we read the remote config and
when we actually use it.

So even though in something like:

    git -c url.$PWD.insteadOf=$PWD clone $PWD dst

we end up with a state were the instead-of structs are broken, nobody is
reading them at that point.

So I think this v2 is doing the right thing.

-Peff

  reply	other threads:[~2026-07-25 16:18 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-25  0:43 [PATCH] remote: plug memory leaks Junio C Hamano
2026-07-25  1:57 ` Junio C Hamano
2026-07-25 16:03 ` [PATCH v2] " Junio C Hamano
2026-07-25 16:18   ` Jeff King [this message]
2026-07-25 17:06     ` Junio C Hamano

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