wrong line number in error message

[p5pRT]

Migrated from rt.perl.org#115768 (status was 'open')

Searchable as RT115768$

[p5pRT]

From @mauke

Created by @mauke

I think the following is a bug in the core but I'm not sure what's going on​:
#!perl
use strict;
use Carp​::Always;

if (1)
{
  []->();
}
__END__

Output​:
Not a CODE reference at try.pl line 5.

(Expected​: ... line 7.)

I can reproduce this with only core modules​:
#!perl
use strict;
BEGIN { use Carp (); $SIG{__DIE__} = sub { Carp​::croak @​_ } }
#use Carp​::Always;
if (1)
{
  []->();
}
__END__

Output​:
Not a CODE reference at try.pl line 7.
at try.pl line 3.
  main​::__ANON__('Not a CODE reference at try.pl line 7.\x{a}') called at try.pl line 5

Here only the last part "... called at try.pl line 5" is wrong.

I briefly tried to debug this with PERLDB_OPTS='NonStop=1' perl -d try.pl, but
that makes the problem disappear.

Perl Info

Flags:
    category=core
    severity=low

Site configuration information for perl 5.16.2:

Configured by mauke at Thu Nov  1 15:23:47 CET 2012.

Summary of my perl5 (revision 5 version 16 subversion 2) configuration:
   
  Platform:
    osname=linux, osvers=2.6.32-5-686, archname=i686-linux
    uname='linux debian-vb 2.6.32-5-686 #1 smp sun sep 23 09:49:36 utc 2012 i686 gnulinux '
    config_args='-Dprefix=/home/mauke/usr -Doptimize=-O2 -flto -Dldflags=-fstack-protector -L/usr/local/lib -O2 -flto -Dlddlflags=-shared -O2 -flto -L/usr/local/lib -fstack-protector -Dcf_email=l.mai@web.de -Dperladmin=none -de'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=undef, use64bitall=undef, 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 -flto',
    cppflags='-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.7.1', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags ='-fstack-protector -L/usr/local/lib -O2 -flto'
    libpth=/usr/local/lib /lib/../lib /usr/lib/../lib /lib /usr/lib /usr/lib/i486-linux-gnu /usr/lib64
    libs=-lnsl -ldl -lm -lcrypt -lutil -lc
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
    libc=/lib/libc-2.11.3.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.11.3'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -flto -L/usr/local/lib -fstack-protector'

Locally applied patches:
    SAVEARGV0 - disable magic open in <ARGV>


@INC for perl 5.16.2:
    /home/mauke/usr/lib/perl5/site_perl/5.16.2/i686-linux
    /home/mauke/usr/lib/perl5/site_perl/5.16.2
    /home/mauke/usr/lib/perl5/5.16.2/i686-linux
    /home/mauke/usr/lib/perl5/5.16.2
    /home/mauke/usr/lib/perl5/site_perl/5.16.1/i686-linux
    /home/mauke/usr/lib/perl5/site_perl/5.16.1
    /home/mauke/usr/lib/perl5/site_perl
    .


Environment for perl 5.16.2:
    HOME=/home/mauke
    LANG=en_US.utf8
    LANGUAGE (unset)
    LC_COLLATE=POSIX
    LD_LIBRARY_PATH=/home/mauke/usr/lib
    LOGDIR (unset)
    PATH=/home/mauke/perl5/perlbrew/bin:/home/mauke/.cabal/bin:/home/mauke/usr/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
    PERLBREW_BASHRC_VERSION=0.55
    PERLBREW_HOME=/home/mauke/.perlbrew
    PERLBREW_ROOT=/home/mauke/perl5/perlbrew
    PERL_BADLANG (unset)
    PERL_UNICODE=SAL
    SHELL=/bin/bash

[p5pRT]

From @cpansprout

On Fri Nov 16 19​:07​:03 2012, mauke- wrote​:

This is a bug report for perl from l.mai@​web.de,
generated with the help of perlbug 1.39 running under perl 5.16.2.

-----------------------------------------------------------------
[Please describe your issue here]

I think the following is a bug in the core but I'm not sure what's
going on​:
#!perl
use strict;
use Carp​::Always;

if (1)
{
[]->();
}
__END__

Output​:
Not a CODE reference at try.pl line 5.

(Expected​: ... line 7.)

I can reproduce this with only core modules​:
#!perl
use strict;
BEGIN { use Carp (); $SIG{__DIE__} = sub { Carp​::croak @​_ } }
#use Carp​::Always;
if (1)
{
[]->();
}
__END__

Output​:
Not a CODE reference at try.pl line 7.
at try.pl line 3.
main​::__ANON__('Not a CODE reference at try.pl line 7.\x{a}')
called at try.pl line 5

Here only the last part "... called at try.pl line 5" is wrong.

I briefly tried to debug this with PERLDB_OPTS='NonStop=1' perl -d
try.pl, but
that makes the problem disappear.

Could this be related to #111982?

--

Father Chrysostomos

[p5pRT]

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

[p5pRT]

From @mauke

On 17.11.2012 20​:13, Father Chrysostomos via RT wrote​:

On Fri Nov 16 19​:07​:03 2012, mauke- wrote​:

This is a bug report for perl from l.mai@​web.de,
generated with the help of perlbug 1.39 running under perl 5.16.2.

-----------------------------------------------------------------
[Please describe your issue here]

I think the following is a bug in the core but I'm not sure what's
going on​:
#!perl
use strict;
use Carp​::Always;

if (1)
{
[]->();
}
__END__

Output​:
Not a CODE reference at try.pl line 5.

(Expected​: ... line 7.)

I can reproduce this with only core modules​:
#!perl
use strict;
BEGIN { use Carp (); $SIG{__DIE__} = sub { Carp​::croak @​_ } }
#use Carp​::Always;
if (1)
{
[]->();
}
__END__

Output​:
Not a CODE reference at try.pl line 7.
at try.pl line 3.
main​::__ANON__('Not a CODE reference at try.pl line 7.\x{a}')
called at try.pl line 5

Here only the last part "... called at try.pl line 5" is wrong.

I briefly tried to debug this with PERLDB_OPTS='NonStop=1' perl -d
try.pl, but
that makes the problem disappear.

Could this be related to #111982?

That bug is about some compilation errors (such as an undeclared
variable under 'use strict') having a caller location of end-of-script
(because perl performs some checks only after it has reached the end of
the code).

It doesn't seem to be immediately related because​:
- this is a runtime error, not compile time
- the bogus line number doesn't point to the end of the script
- in fact, it points to an *earlier* statement (the 'if' controlling the
block)

But maybe there's a deeper connection?

[p5pRT]

From @cpansprout

On Sat Nov 17 12​:28​:28 2012, mauke- wrote​:

On 17.11.2012 20​:13, Father Chrysostomos via RT wrote​:

Could this be related to #111982?

That bug is about some compilation errors (such as an undeclared
variable under 'use strict') having a caller location of end-of-script
(because perl performs some checks only after it has reached the end of
the code).

It doesn't seem to be immediately related because​:
- this is a runtime error, not compile time
- the bogus line number doesn't point to the end of the script
- in fact, it points to an *earlier* statement (the 'if' controlling the
block)

But maybe there's a deeper connection?

That was just a hunch, based on a quick reading. It’s probably unrelated.

In this case I suspect it has to do with a nextstate op being optimised
away so a different nextstate op is active. Again, I haven’t looked at
it carefully, as I am in the middle of fixing 5 more memory leaks I’ve
just discovered.

--

Father Chrysostomos

[p5pRT]

From @ikegami

On Sat, Nov 17, 2012 at 4​:12 PM, Father Chrysostomos via RT <
perlbug-followup@​perl.org> wrote​:

In this case I suspect it has to do with a nextstate op being optimised
away so a different nextstate op is active.

$ perl -MO=Concise -e'if (1)
{
  []->();
}
'
7 <@​> leave[1 ref] vKP/REFC ->(end)
1 <0> enter ->2
2 <;> nextstate(main 3 -e​:1) v​:{ ->3 <--- This is the one that is
used.
- <@​> scope vK ->7
- <0> ex-nextstate v ->3 <--- This would have the
correct info, but optimised away
6 <1> entersub[t1] vKS/TARG,1 ->7
- <1> ex-list K ->6
3 <0> pushmark s ->4
- <1> ex-rv2cv K ->-
5 <@​> anonlist sK* ->6
4 <0> pushmark s ->5
-e syntax OK

[p5pRT]

From @cpansprout

On Sun Nov 18 18​:09​:20 2012, ikegami@​adaelis.com wrote​:

On Sat, Nov 17, 2012 at 4​:12 PM, Father Chrysostomos via RT <
perlbug-followup@​perl.org> wrote​:

In this case I suspect it has to do with a nextstate op being optimised
away so a different nextstate op is active.

$ perl -MO=Concise -e'if (1)
{
[]->();
}
'
7 <@​> leave[1 ref] vKP/REFC ->(end)
1 <0> enter ->2
2 <;> nextstate(main 3 -e​:1) v​:{ ->3 <--- This is the one
that is
used.
- <@​> scope vK ->7
- <0> ex-nextstate v ->3 <--- This would have the
correct info, but optimised away
6 <1> entersub[t1] vKS/TARG,1 ->7
- <1> ex-list K ->6
3 <0> pushmark s ->4
- <1> ex-rv2cv K ->-
5 <@​> anonlist sK* ->6
4 <0> pushmark s ->5
-e syntax OK

Aha, so it looks as though pp_ctl.c​:pp_caller needs to use
util.c​:S_closest_cop.

Debugging without looking at the code seems to be working. :-)

--

Father Chrysostomos

[p5pRT]

From @cpansprout

Fixed in 2550212.

--

Father Chrysostomos

[p5pRT]

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

[p5pRT]

From @cpansprout

On Sun Sep 01 11​:43​:04 2013, sprout wrote​:

Fixed in 2550212.

Though, actually, there are some cases where it doesn’t work, (e.g.,
eval "s{}\n{foo()}e"), because the context stack has no pointer to the
entersub op, but rather its ->op_next. Sometimes ->op_next is null (in
that subst example).

Would it be reasonable to put the entersub op in the context stack (as
retop) and have pp_leavesub do retop->op_next instead of just retop?

--

Father Chrysostomos

[p5pRT]

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