From: Justin Tobler <jltobler@gmail.com>
Date: Sun, 22 Feb 2026 17:19:29 GMT
Subject: Re: [PATCH] object-file: use `container_of()` to convert from base types
Message-ID: <aZs6OvvBB4WPNx8j@denethor>
In-Reply-To: <20260222094158.GA1319383@coredump.intra.peff.net>

On 26/02/22 04:41AM, Jeff King wrote:
> On Sat, Feb 21, 2026 at 11:07:08PM -0800, Junio C Hamano wrote:
> 
> > Perhaps a fix-up patch on top of the topic branch like this?
> > 
> > ----- >8 -----
> > Subject: [PATCH] object-file.c: avoid container_of() of a NULL container
> > [...]
> >  static void prepare_loose_object_transaction(struct odb_transaction *base)
> >  {
> > -	struct odb_transaction_files *transaction =
> > -		container_of(base, struct odb_transaction_files, base);
> > +	struct odb_transaction_files *transaction = NULL;
> > +
> > +	if (base)
> > +		transaction =
> > +			container_of(base, struct odb_transaction_files, base);
> 
> That works, but you can also use container_of_or_null() in the
> initializer. IMHO the result is easier to read.

I agree that container_of_or_null() looks a bit better here. Happy to
know about this now.

Thanks,
-Justin