Re: [PATCH 6/7] xdiff: remove xdl_malloc() wrapper, use malloc(), not xmalloc()

From: Jeff King <peff@peff.net>
Date: Jul 8, 2022, 19:35 UTC
Message-ID: <YsiHGliw2dYmGcDY@coredump.intra.peff.net>
In-Reply-To: <patch-6.7-33d93f121a9-20220708T140354Z-avarab@gmail.com>

On Fri, Jul 08, 2022 at 04:20:18PM +0200, Ævar Arnfjörð Bjarmason wrote:

Show 13 quoted lines

> As noted in 36c83197249 (xdiff: use xmalloc/xrealloc, 2019-04-11) the
> reason we have xdl_malloc() in the first place was to make the xdiff
> code safer, it was not handling some allocation failures correctly at
> the time.
> 
> But as noted in that commit doing this was intended as a stopgap, as
> various code in xdiff/* did not correctly handle allocation failures,
> and would have segfaulted if malloc() returned NULL.
> 
> But since then and after preceding commits we can be confident that
> malloc() failures are handled correctly. All of these users of
> xdl_malloc() are checking their return values, and we're returning
> -1 (or similar ) to the top-level in case of failures.

This is also losing the other parts mentioned in 36c83197249: respecting GIT_ALLOC_LIMIT and any memory reclamation strategies.

I think you'd want an xmalloc_gently() instead of a raw malloc().

For the same reason, I suspect it's better to leave this with a layer of preprocessor indirection. Even if we chose to use malloc() here, libgit2 might not, and having the macro makes it easier to share the code.

-Peff