How is Carp's @CARP_NOT supposed to work?

Hi Perl5 developers,

I've tried to reduce the use of $Carp::CarpLevel in some CPAN module and
found that @CARP_NOT works differently than I understood it. It calls
other code and currently uses `local $Carp::CarpLevel += 2` to reference
the user code in a croak() message.

The test file for @CARP_NOT's logic claims it is transitive. So I 
expected
that pushing several package names to @CARP_NOT in a module low in the
stacktrace effectively excludes these packages from error messages
creates above in the stacktrace.

I edited the test file based on the current `bleed` branch to verify my
understanding of the situation. See the diff for an example for the
description above.

https://github.com/dboehmer/perl5/commit/1961db115cd4ccdffce6b2c005ea1654e67529d8

Please have a look at the test file and tell me

- whether @CARP_NOT has ever been supposed to work like this

- whether @CARP_NOT could be extended to work like this and if you
support such a change

Kind regards
Daniel Böhmer alias DBOEHMER

• How is Carp's @CARP_NOT supposed to work? by Daniel Böhmer