From-munge not being reversed on mbox import

[Kyle Meyer <kyle@kyleam.com>]

I'm feeding mbox files created with Konstantin Ryabitsev's
list-archive-maker.py script [^1] to import_vger_from_mbox.  Looking
through the result, I noticed some ">From" lines.  Here's an example:

  https://yhetil.org/orgmode/871rpt9zc4.fsf@kyleam.com/

If I'm following the code correctly, that leads to an import_mbox call,
which in turn calls mb_add:

   sub mb_add ($$$$) {
       my ($im, $variant, $filter, $msg) = @_;
       $$msg =~ s/(\r?\n)+\z/$1/s;
       my $mime = PublicInbox::MIME->new($msg);
       if ($variant eq 'mboxrd') {
               $$msg =~ s/^>(>*From )/$1/sm;
       } elsif ($variant eq 'mboxo') {
               $$msg =~ s/^>From /From /sm;
       }
   [...]

So, it appears the ">From" _should_ be getting reversed.  To eliminate
any stupid things I may have done when creating the archive, I looked
for a message on meta that has an in-body line starting with "From" and
found

  https://public-inbox.org/meta/20200121222924.ioz5ve2sg65zcuoy@chatter.i7.local/

So I downloaded the public-inbox generated mbox and fed it to
import_vger_from_mbox:

  curl -s https://public-inbox.org/meta/20200121222924.ioz5ve2sg65zcuoy@chatter.i7.local/t.mbox.gz \
   | zcat | scripts/import_vger_from_mbox testing emacs-orgmode@gnu.org ~/inboxes/testing

That too leaves a ">From" in the body:

  https://yhetil.org/testing/20200121222924.ioz5ve2sg65zcuoy@chatter.i7.local/

Any idea what's going wrong here?


[^1]: https://git.kernel.org/pub/scm/linux/kernel/git/mricon/korg-helpers.git/plain/list-archive-maker.py