Re: [PATCH 1/2] stop calling UNLEAK() before die()

From: Jeff King <peff@peff.net>
Date: Aug 14, 2020, 10:17 UTC
Message-ID: <20200814101706.GC3312240@coredump.intra.peff.net>
In-Reply-To: <275f3f6c-77ed-fddd-8f79-28f25b257362@gmail.com>

On Thu, Aug 13, 2020 at 02:08:45PM -0400, Derrick Stolee wrote:

Show 11 quoted lines

> On 8/13/2020 11:55 AM, Jeff King wrote:
> > The point of UNLEAK() is to make a reference to a variable that is about
> > to go out of scope so that leak-checkers will consider it to be
> > not-leaked. Doing so right before die() is therefore pointless; even
> > though we are about to exit the program, the variable will still be on
> > the stack and accessible to leak-checkers.
> > 
> > These annotations aren't really hurting anything, but they clutter the
> > code and set a bad example of how to use UNLEAK().
> 
> Good justification. I'll stop being a bad example ;)

To be fair, it seems clear that UNLEAK() as a concept is rather confusing. I really never intended anybody to start sprinkling it around the code. It was meant to be a tool for folks who are interested in running leak-checkers to do in-code annotations (for "yes, I know this leaks but not until the program effectively ends").

I certainly don't mind if people writing new code preemptively annotate this kind of leak. But I also wouldn't really encourage authors to put a lot of effort into it, given the current state of the annotations.

-Peff