BBC: fed3309 breaks XS-Install

[jkeenan]

Bisecting with this invocation:

perl Porting/bisect.pl \
--module=XS::Install \
--start=v5.43.5 \
--end=f430ad845a2f4f64125379fb1e31ac5bd85a4e91

... pointed to fed3309 as the breaking commit:

fed3309b070153d25a28a0fbd199224d628f105d is the first bad commit
commit fed3309b070153d25a28a0fbd199224d628f105d
Author: David Mitchell <davem@iabyn.com>
Date:   Sat Oct 25 15:38:44 2025 +0100
Commit:     David Mitchell <davem@iabyn.nospamdeletethisbit.com>
CommitDate: Wed Dec 17 13:14:37 2025 +0000

    ParseXS: refactor: add  Node::MODULE    

Reports:
http://fast2-matrix.cpantesters.org/?dist=XS-Install;os=linux;reports=1#sl=6,1

Sample failure report:
https://www.cpantesters.org/cpan/report/4bbb6922-dcf3-11f0-8c54-aabd432e6cba

Excerpt from failure report:

Use of uninitialized value $sig in pattern match (m//) at /home/jkeenan/.cpan/build/XS-Install-1.4.0-0/blib/lib/XS/Install/ParseXS.pm line 227, <__ANONIO__> line 226.
Use of uninitialized value $sig in concatenation (.) or string at /home/jkeenan/.cpan/build/XS-Install-1.4.0-0/blib/lib/XS/Install/ParseXS.pm line 227, <__ANONIO__> line 226.
Use of uninitialized value in concatenation (.) or string at /home/jkeenan/.cpan/build/XS-Install-1.4.0-0/blib/lib/XS/Install/ParseXS.pm line 227, <__ANONIO__> line 226.
Use of uninitialized value in concatenation (.) or string at /home/jkeenan/.cpan/build/XS-Install-1.4.0-0/blib/lib/XS/Install/ParseXS.pm line 227, <__ANONIO__> line 226.
bad signature: '', at , function  at /home/jkeenan/.cpan/build/XS-Install-1.4.0-0/blib/lib/XS/Install/ParseXS.pm line 227, <__ANONIO__> line 226.
t/parsexs/parsexs.t ...... 
Dubious, test returned 25 (wstat 6400, 0x1900)
No subtests run 

Briefly noted upstream: https://rt.cpan.org/Ticket/Display.html?id=172363

@iabyn can you take a look?

[iabyn]

On Sun, Dec 21, 2025 at 05:40:29AM -0800, James E Keenan wrote: Bisecting with this invocation:

...

commit fed3309 Author: David Mitchell ***@***.***> Date: Sat Oct 25 15:38:44 2025 +0100 ParseXS: refactor: add Node::MODULE Excerpt from failure report: ``` Use of uninitialized value $sig in pattern match (m//) at /home/jkeenan/.cpan/build/XS-Install-1.4.0-0/blib/lib/XS/Install/ParseXS.pm line 227, <__ANONIO__> line 226.

The line which is raising the error is within a function in the CPAN module. This function is a replacement for the standard ExtUtils::ParseXS::fetch_para() method; being monkey-patched via: *ExtUtils::ParseXS::fetch_para = sub { ...}; Since the fetch_para() method is undocumented and is private to ExtUtils::ParseXS, the CPAN module is basically rummaging around in the private guts of ExtUtils::ParseXS. So it's not surprising that it no longer works following my recent major refactoring of ExtUtils::ParseXS. It's something for the module's author to fix. If I were to hazard a guess, I suspect it's probably because following my commit, fetch_para() is no longer responsible for processing MODULE lines.