Re: [PATCH nft 2/2] debug: include kernel set information on cache fill

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Thu, Nov 21, 2024 at 01:02:42PM +0100, Florian Westphal wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > > Only options I see is to add a feature test file for this support,
> > > and then either disabling dump validation if it failed or adding
> > > additonal/alternative dump file.
> > 
> > Oh right, tests!
> > 
> > Probably tests/shell can be workaround to remove # count X before
> > comparing output.
> > 
> > It won't look nice, but I think tests/shell can carry on this burden.
> > This means # count N will not be checked in old and new kernels.
> > 
> > To validate # count N, we can still rely on tests/py and the debug
> > output as you propose.
> > 
> > Not great, but does this sound sensible to you?
> 
> 1. Add new feature test
> 2. Update dump files to include "# count xxx"
> 3. when diff -u fails, do postprocess on recorded
>    dump file, i.e. sed s/# count.*//g 
> 4. repeat diff with postprocessed recorded dump
>    if ok -> ok, else dump failure
> 
> Does that sound ok?

OK, still one more aspect I'd like to discuss.

> AFAICS we only need to update < 10 dump files,
> so churn is not too bad.
>
> Alternative is to always store postprocessed
> dumps and then always run sed before diff, but I think
> its better to do the extra mile.

rbtree going leaks a raw count of independent interval values which is
going to be awkward to the user.