BBC: bleadperl breaks ETHER/Package-Stash-XS-0.30.tar.gz on DEBUGGING perls

[andk]

Description

Sample fail report with v5.43.4: https://www.cpantesters.org/cpan/report/0cf94468-b118-11f0-801a-aef4e0e1b722

From that report the assertion:

perl: regexec.c:856: Perl_pregexec: Assertion `stringarg < strend' failed.

More recent fail report with v5.43.4-71-g4092daf53e: https://www.cpantesters.org/cpan/report/f1120b74-b7eb-11f0-8ac1-e4b6dff035f7

From that report the assertion is:

perl: regexec.c:820: Perl_pregexec: Assertion `stringarg < strend' failed.

I also have a result at hand with bleadperl v5.43.4-93-gb9a78e5da4 with the same assertion that I have not uploaded.

@karenetheridge , you're probably interested

Maybe relevant XRef: #23854

Steps to Reproduce

cpan -i ETHER/Package-Stash-XS-0.30.tar.gz

Expected behavior

test and install OK

Perl configuration

# perl -V output goes here
Summary of my perl5 (revision 5 version 43 subversion 4) configuration:
 Commit id: 1b96d25e5a053990c9e8709996d2ff1220ceb98b
 Platform:
 osname=linux
 osvers=6.12.38+deb13-amd64
 archname=x86_64-linux-thread-multi
 uname='linux k93msid 6.12.38+deb13-amd64 #1 smp preempt_dynamic debian 6.12.38-1 (2025-07-16) x86_64 gnulinux '
 config_args='-Dprefix=/home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.43.4/29fb -Dmyhostname=k93msid -Dinstallusrbinperl=n -Uversiononly -Dusedevel -des -Ui_db -Dlibswanted=cl pthread socket inet nsl gdbm dbm malloc dl ld sun m crypt sec util c cposix posix ucb BSD gdbm_compat -Duseithreads -Uuselongdouble -DEBUGGING=both'
 hint=recommended
 useposix=true
 d_sigaction=define
 useithreads=define
 usemultiplicity=define
 use64bitint=define
 use64bitall=define
 uselongdouble=undef
 usemymalloc=n
 default_inc_excludes_dot=define
 Compiler:
 cc='cc'
 ccflags ='-D_REENTRANT -D_GNU_SOURCE -fwrapv -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
 optimize='-O2 -g'
 cppflags='-D_REENTRANT -D_GNU_SOURCE -fwrapv -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
 ccversion=''
 gccversion='14.3.0'
 gccosandvers=''
 intsize=4
 longsize=8
 ptrsize=8
 doublesize=8
 byteorder=12345678
 doublekind=3
 d_longlong=define
 longlongsize=8
 d_longdbl=define
 longdblsize=16
 longdblkind=3
 ivtype='long'
 ivsize=8
 nvtype='double'
 nvsize=8
 Off_t='off_t'
 lseeksize=8
 alignbytes=8
 prototype=define
 Linker and Libraries:
 ld='cc'
 ldflags =' -fstack-protector-strong -L/usr/local/lib'
 libpth=/usr/local/lib /usr/lib/x86_64-linux-gnu /usr/lib /usr/lib64
 libs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
 perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
 libc=/lib/x86_64-linux-gnu/libc.so.6
 so=so
 useshrplib=false
 libperl=libperl.a
 gnulibc_version='2.41'
 Dynamic Linking:
 dlsrc=dl_dlopen.xs
 dlext=so
 d_dlsymun=undef
 ccdlflags='-Wl,-E'
 cccdlflags='-fPIC'
 lddlflags='-shared -O2 -g -L/usr/local/lib -fstack-protector-strong'


Characteristics of this binary (from libperl): 
 Compile-time options:
 DEBUGGING
 HAS_LONG_DOUBLE
 HAS_STRTOLD
 HAS_TIMES
 MULTIPLICITY
 PERLIO_LAYERS
 PERL_COPY_ON_WRITE
 PERL_DONT_CREATE_GVSV
 PERL_HASH_FUNC_SIPHASH13
 PERL_HASH_USE_SBOX32
 PERL_MALLOC_WRAP
 PERL_OP_PARENT
 PERL_PRESERVE_IVUV
 PERL_TRACK_MEMPOOL
 PERL_USE_DEVEL
 PERL_USE_SAFE_PUTENV
 USE_64_BIT_ALL
 USE_64_BIT_INT
 USE_ITHREADS
 USE_LARGE_FILES
 USE_LOCALE
 USE_LOCALE_COLLATE
 USE_LOCALE_CTYPE
 USE_LOCALE_NUMERIC
 USE_LOCALE_TIME
 USE_PERLIO
 USE_PERL_ATOF
 USE_REENTRANT_API
 USE_THREAD_SAFE_LOCALE
 Built under linux
 Compiled at Oct 24 2025 05:50:42
 %ENV:
 PERL5LIB=""
 PERL5OPT=""
 PERL5_CPANPLUS_IS_RUNNING="2506538"
 PERL5_CPAN_IS_RUNNING="2506538"
 PERL_CANARY_STABILITY_NOPROMPT="1"
 PERL_MM_USE_DEFAULT="1"
 PERL_USE_UNSAFE_INC="1"
 @INC:
 /home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.43.4/29fb/lib/site_perl/5.43.4/x86_64-linux-thread-multi
 /home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.43.4/29fb/lib/site_perl/5.43.4
 /home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.43.4/29fb/lib/5.43.4/x86_64-linux-thread-multi
 /home/sand/src/perl/repoperls/installed-perls/host/k93msid/v5.43.4/29fb/lib/5.43.4
 .

[jkeenan]

Bisecting with the following invocation:

perl Porting/bisect.pl -DDEBUGGING -Duseithreads \
--start=v5.42.0 \
--module=Package::Stash::XS

... pointed to 45ea12d (v5.43.3-167-g45ea12db26) as the first bad commit:

commit 45ea12db26f8c70d27d2452f78ffb3abf1dce644
Author: Karl Williamson <khw@cpan.org>
AuthorDate: Sat Sep 27 17:16:56 2025 -0600
Commit: Karl Williamson <khw@cpan.org>
CommitDate: Sun Oct 12 13:57:57 2025 -0600

 embed.fnc: Add MPTR constraints
 
 This is the first use of the new MPTR constraint that is used to
 generate an assertion that a pointer is somewhere in the middle of a
 string.
 
 I removed now redundant asserts that were in the functions, and now are
 included in the ARGS_ASSERT macros

@khwilliamson, can you take a look? Thanks.

[andk]

Not that I like to sound pushy, but Package-Stash-XS is a reverse dependency of Moose, so bleadperl has no Moose with DEBUGGING perls and 5.43.5 is about to be released.

I just verified: v5.43.4-142-gf7c24445e8 still fails with the assertion

regexec.c:820: Perl_pregexec: Assertion `stringarg < strend' failed.

Is there a known reason why this is stuck? @jkeenan , @khwilliamson ?

[Leont]

My guess would be that this fails if stringarg == strend, that < should probably be a <=.

[iabyn]

I've just pushed PR #23980, which fixes the immediate issue. But, @khwilliamson, what do you think about my comments in the commit message about SPTR <= EPTR? What is the correct general fix?