ExtUtils-CBuilder/t/03-cplusplus.t failed when ENV{CXX} is defined

[jplesnik]

Module: ExtUtils-CBuilder

Description

I tried to build Perl based on blead for Fedora and got following error:

#   Failed test 'did not search PATH for C++ compiler when given absolute path to C compiler'
#   at t/03-cplusplus.t line 73.
#          got: 'g++'
#     expected: '/builddir/build/BUILD/perl-5.41.12-build/perl-5.41.12/dist/ExtUtils-CBuilder/some/directory/what/doesnt/exist/cc'
# Looks like you failed 1 test of 7.
../dist/ExtUtils-CBuilder/t/03-cplusplus.t ........................... 
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/7 subtests 

The failure is caused by the $ENV{CXX} variable being defined.

Using local $ENV{CXX}; in the test fixes the failure.

Complete log is on
https://jplesnik.fedorapeople.org/5.42/build.log

Steps to Reproduce
Set CXX
CXX=g++; export CXX
and run the test

Expected behavior
Test should pass.

Perl configuration
Used perl blead

[Leont]

This must be a regression caused by #23146. Sounds like a bug in the test (for not taking $CXX into account), not in the code itself.

[jkeenan]

This must be a regression caused by #23146. Sounds like a bug in the test (for not taking $CXX into account), not in the code itself.

Perhaps this change in blead code:

commit ea0856c6750e984cdc3f73e06ba82601bb5f1a87
Author:     Chris 'BinGOs' Williams <chris@bingosnet.co.uk>
AuthorDate: Sat Apr 26 16:16:34 2025 +0100
Commit:     Chris 'BinGOs' Williams <chris@bingosnet.co.uk>
CommitDate: Sat Apr 26 16:16:34 2025 +0100

    Fix finding the correct cplusplus compiler

@bingos, can you take a look? Thanks.

[Leont]

No it's 02915d0. Probably either the test should be skipped entirely if $CXX is set, or $CXX needs to be (temporarily) unset.