Re: [PATCH] add support for -Wmismatched-dealloc

[DJ Delorie <dj@redhat.com>]

Martin Sebor via Libc-alpha <libc-alpha@sourceware.org> writes:
>> realpath only returns a pointer to the heap if RESOLVED is null, so the
>> annotation is wrong here.
>> 
>
> This is intentional.  When realpath() returns the last argument
> (when it's nonnull) passing the returned pointer to free will not
> be diagnosed but passing it to some other deallocator not associated
> with the function will be.  That means for example that passing
> a pointer allocated by C++ operator new() to realpath() and then
> deleting the pointer returned from the function as opposed to
> the argument will trigger a false positive.  I decided this was
> an okay trade-off because unless the function allocates memory
> I expect the returned pointer to be ignored (similarly to how
> the pointer returned from memcpy is ignored).  If you don't like
> the odds I can remove the attribute from the function until we
> have one that captures this conditional return value (I'd like
> to add one in GCC 12).

Do we have a resolution on this?  I think deferring the realpath part of
this patch until it can be handled correctly is a reasonable solution.
I think an unwarned leak is better than false warnings.

The rest of the patch looks fine and has been reviewed...