From @andk

git bisect

commit c72a4ee
Author​: Father Chrysostomos <sprout@​cpan.org>
Date​: Sat Jun 22 16​:14​:24 2013 -0700

  sv.c​: Make sv_force_normal always croak on ro SVs

diagnostics

http​://www.cpantesters.org/cpan/report/ea638256-d122-11e3-b311-afc8310f0ce5

rt.cpan ticket

https://rt.cpan.org/Ticket/Display.html?id=95228

perl -V

Summary of my perl5 (revision 5 version 19 subversion 3) configuration​:
  Commit id​: f865d60
  Platform​:
  osname=linux, osvers=3.13-1-amd64, archname=x86_64-linux
  uname='linux k83 3.13-1-amd64 #1 smp debian 3.13.7-1 (2014-03-25)
  x86_64 gnulinux '
  config_args='-Dprefix=/home/sand/src/perl/repoperls/installed-perls/perl/v5.19.3/165a
  -Dmyhostname=k83 -Dinstallusrbinperl=n -Uversiononly -Dusedevel -des
  -Ui_db -Uuseithreads -Uuselongdouble -DDEBUGGING=-g'
  hint=recommended, useposix=true, d_sigaction=define
  useithreads=undef, usemultiplicity=undef
  useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
  use64bitint=define, use64bitall=define, uselongdouble=undef
  usemymalloc=n, bincompat5005=undef
  Compiler​:
  cc='cc', ccflags ='-fno-strict-aliasing -pipe -fstack-protector
  -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
  optimize='-O2 -g',
  cppflags='-fno-strict-aliasing -pipe -fstack-protector
  -I/usr/local/include'
  ccversion='', gccversion='4.8.2', gccosandvers=''
  intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
  d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
  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 -L/usr/local/lib'
  libpth=/usr/local/lib /lib/x86_64-linux-gnu /lib/../lib
  /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /usr/lib
  libs=-lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc -lgdbm_compat
  perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
  libc=, so=so, useshrplib=false, libperl=libperl.a
  gnulibc_version='2.18'
  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'

Characteristics of this binary (from libperl)​:
  Compile-time options​: HAS_TIMES PERLIO_LAYERS PERL_DONT_CREATE_GVSV
  PERL_HASH_FUNC_ONE_AT_A_TIME_HARD
  PERL_MALLOC_WRAP
  PERL_NEW_COPY_ON_WRITE PERL_PRESERVE_IVUV
  PERL_USE_DEVEL USE_64_BIT_ALL USE_64_BIT_INT
  USE_LARGE_FILES USE_LOCALE USE_LOCALE_COLLATE
  USE_LOCALE_CTYPE USE_LOCALE_NUMERIC USE_PERLIO
  USE_PERL_ATOF
  Built under linux
  Compiled at Apr 29 2014 04​:08​:46
  %ENV​:
  PERL5LIB=""
  PERL5OPT=""
  PERL5_CPANPLUS_IS_RUNNING="8840"
  PERL5_CPAN_IS_RUNNING="8840"
  PERL_MM_USE_DEFAULT="1"
  @​INC​:
  /home/sand/src/perl/repoperls/installed-perls/perl/v5.19.3/165a/lib/site_perl/5.19.3/x86_64-linux
  /home/sand/src/perl/repoperls/installed-perls/perl/v5.19.3/165a/lib/site_perl/5.19.3
  /home/sand/src/perl/repoperls/installed-perls/perl/v5.19.3/165a/lib/5.19.3/x86_64-linux
  /home/sand/src/perl/repoperls/installed-perls/perl/v5.19.3/165a/lib/5.19.3
  .

--
andreas

From @tonycoz

On Thu May 01 11​:55​:55 2014, andreas.koenig.7os6VVqR@​franz.ak.mind.de wrote​:

git bisect
----------
commit c72a4ee
Author​: Father Chrysostomos <sprout@​cpan.org>
Date​: Sat Jun 22 16​:14​:24 2013 -0700

sv.c​: Make sv_force_normal always croak on ro SVs

diagnostics
-----------
http​://www.cpantesters.org/cpan/report/ea638256-d122-11e3-b311-
afc8310f0ce5

rt.cpan ticket
--------------
https://rt.cpan.org/Ticket/Display.html?id=95228

Looking at this, I think it's a bug in namespace​::alias.

It's attempting to modify the SV attached to an OP_CONST, which is marked readonly​:

Breakpoint 2, Perl_sv_force_normal_flags (sv=0x105aa08, flags=4) at sv.c​:5023
5023 Perl_croak_no_modify();
(gdb) call Perl_sv_dump(sv)
SV = PV(0x1021450) at 0x105aa08
  REFCNT = 1
  FLAGS = (POK,READONLY,IsCOW,pPOK)
  PV = 0xb0ea30 "MyAlias​::fun"\0
  CUR = 12
  LEN = 16
  COW_REFCNT = 1
(gdb) bt
#0 Perl_sv_force_normal_flags (sv=0x105aa08, flags=4) at sv.c​:5023
#1 0x0000000000500dd2 in Perl_sv_setsv_flags (dstr=dstr@​entry=0x105aa08,
  sstr=sstr@​entry=0x105a9a8, flags=flags@​entry=2) at sv.c​:4062
#2 0x00007ffff5347050 in check_alias (op=0xb0e800, user_data=<optimized out>)
  at alias.xs​:202
#3 0x00007ffff5759e1a in check_cb (op=<optimized out>) at Check.xs​:49
#4 0x000000000046b601 in Perl_yylex () at toke.c​:7280
#5 0x000000000048180b in Perl_yyparse (gramtype=gramtype@​entry=258)
  at perly.c​:343
#6 0x000000000044a2f2 in S_parse_body (env=env@​entry=0x0,
  xsinit=xsinit@​entry=0x422ab0 <xs_init>) at perl.c​:2298
#7 0x000000000044b987 in perl_parse (my_perl=<optimized out>,
  xsinit=xsinit@​entry=0x422ab0 <xs_init>, argc=4, argv=0x7fffffffd6d8,
  env=env@​entry=0x0) at perl.c​:1607
#8 0x0000000000422910 in main (argc=4, argv=0x7fffffffd6d8,
  env=0x7fffffffd700) at perlmain.c​:112
(gdb) call Perl_op_dump((OP*)0xb0e800)
{
1 TYPE = const ===> 1
  FLAGS = (SCALAR,SLABBED)
  SV = PV("MyAlias​::fun"\0)
}

I suspect the only workaround for the author would be to switch SvREADONLY() off for the modification.

Tony

The RT System itself - Status changed from 'new' to 'open'

From @rjbs

This has been filed as https://rt.cpan.org/Ticket/Display.html?id=95228 so I am resolving it in rt.perl.org

--
rjbs

@rjbs - Status changed from 'open' to 'resolved'