t/op/magic.t failing on AlmaLinux 8.

[toddr]

I built using:

./Configure -des -Dusedevel -Duseithreads -Doptimize="-O2 -pipe -fstack-protector -fno-strict-aliasing"

The verbose output is a little hard to read but...

t/op/magic ... 1..208
ok 1 - *SIG appears to be defined at the outset
ok 2 - *^OPEN appears to be defined at the outset
ok 3 - *^TAINT appears to be defined at the outset
...
ok 99 - Assigning $^I does not clobber $^O
ok 100 - test $^P = 0
ok 101 - test $^P = 1
ok 102 - Set process name through argv[0] ( 136098 pts/0    S+     0:00 Good Morning, Dave                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           )
ok 103 - Set process name through prctl() ( 136098 pts/0    S+     0:00 Good Morning, D)
ok 104 - compare $0 to UTF8-flagged
ok 105 - compare $0 to non-UTF8-flagged
# Failed test 106 - /proc cmdline shows as expected (compare to UTF8-flagged) at op/magic.t line 480
#      got "?\000                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           "
not ok 106 - /proc cmdline shows as expected (compare to UTF8-flagged)
# expected "?"
# Failed test 107 - /proc cmdline shows as expected (compare to non-UTF8-flagged) at op/magic.t line 482
#      got "?\000                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           "
# expected "?"
# Failed test 111 - .. and /proc cmdline shows that at op/magic.t line 504
#      got "hahaĀhoho\000                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  "
# expected "hahaĀhoho"
FAILED at test 106
Failed 1 test out of 1, 0.00% okay.
	op/magic.t
### Since not all tests were successful, you may want to run some of
### them individually and examine any diagnostic messages they produce.
### See the INSTALL document's section on "make test".
### You may have to set your dynamic library search path,
### LD_LIBRARY_PATH, to point to the build directory:
###   setenv LD_LIBRARY_PATH `pwd`:$LD_LIBRARY_PATH; cd t; ./perl harness
###   LD_LIBRARY_PATH=`pwd`:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; cd t; ./perl harness
###   export LD_LIBRARY_PATH=`pwd`:$LD_LIBRARY_PATH; cd t; ./perl harness
### for csh-style shells, like tcsh; or for traditional/modern
### Bourne-style shells, like bash, ksh, and zsh, respectively.
Elapsed: 3 sec
u=0.01  s=0.00  cu=0.18  cs=0.18  scripts=1  tests=208

I have bisected the failure to:

2d3b3561a39bb17fd6003fb262f52b3bc800770e is the first bad commit
commit 2d3b3561a39bb17fd6003fb262f52b3bc800770e
Author: Felipe Gasper <felipe@felipegasper.com>
Date:   Fri Jan 7 14:28:39 2022 -0500

    Properly handle UTF8-flagged strings when assigning to $0.
    
    Issue #19331: Use of SvPV_const and SvPV_force in S_set_dollarzero()
    wrote the PV internals directly to argv, which causes an improper UTF-8
    encode if the SV is UTF8-flagged/upgraded.
    
    This fixes that doing a downgrade prior to those SvPV* calls. If the
    string contains wide characters (and thus cannot be downgraded) a
    warning is thrown; this mirrors preexisting behavior with %ENV, print,
    and other output channels that convert Perl SVs to bytes.
    
    The relevant documentation is also updated.

 mg.c              | 10 +++++++
 pod/perldelta.pod |  7 +++++
 pod/perlvar.pod   |  4 +++
 t/op/magic.t      | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-

[jkeenan]

Committed relatively recently (this dev cycle):

commit 2d3b3561a39bb17fd6003fb262f52b3bc800770e
Author:     Felipe Gasper <felipe@felipegasper.com>
AuthorDate: Fri Jan 7 14:28:39 2022 -0500
Commit:     Karl Williamson <khw@cpan.org>
CommitDate: Sat Mar 5 21:06:05 2022 -0700

@FGasper, @khwilliamson, can you take a look?

@toddr, can you identify specific aspects of Alma Linux that might cause this problem?

[toddr]

specically
$>git tag --contains 2d3b356
v5.35.10
v5.35.11

[toddr]

@toddr, can you identify specific aspects of Alma Linux that might cause this problem?

Not really. @FGasper has the same access as I do to A8 so it should be hard for him to look at.

[xenu]

Those redundant spaces in /proc/<pid>/cmdline are caused by a bug in Linux kernel. It was broken in kernels from 4.18 to 5.2 (inclusive).

It was reported here: https://lore.kernel.org/lkml/alpine.LNX.2.21.1904052326230.3249@kich.toxcorp.com/

I guess the right fix would be to skip this test on the affected kernels.

[FGasper]

diff --git a/t/op/magic.t b/t/op/magic.t
index d879406f58..3ef028d6d3 100644
--- a/t/op/magic.t
+++ b/t/op/magic.t
@@ -469,7 +469,7 @@ EOP
     open my $rfh, '<', "/proc/$$/cmdline"
       or skip "failed to read '/proc/$$/cmdline': $!", $skip;
     my $got = do { local $/; <$rfh> };
-    $got=~s/\0\z//;
+    $got=~s/\0\s*\z//;
     return $got;
   };

^^ Fixes it for me.

[leonerd]

FGasper's PR #19691 should fix this. Please merge ASAP

[toddr]

This has been merged.