perl5db.pl: Undefined subroutine &DB::db_warn called

[p5pRT]

Migrated from rt.perl.org#123553 (status was 'resolved')

Searchable as RT123553$

[p5pRT]

From @choroba

Created by @choroba

Perl debugger sometimes tries to call a non-existent subroutine
db_warn. It's real name is _db_warn, though.

How to replicate​:

perl -d -e1
!/

Output​:

/bin/bash​: /​: Is a directory
Undefined subroutine &DB​::db_warn called at /usr/lib/perl5/5.18.1/perl5db.pl line 6740.
  at /usr/lib/perl5/5.18.1/perl5db.pl line 6740.
  DB​::_db_system('/bin/bash', '-c', '/') called at /usr/lib/perl5/5.18.1/perl5db.pl line 3923
  DB​::Obj​::_handle_sh_command('DB​::Obj=HASH(0x105df48)') called at /usr/lib/perl5/5.18.1/perl5db.pl line 2992
  DB​::DB called at -e line 1

Patch to fix the issue attached.

  Choroba

Perl Info

Flags:
     category=library
     severity=low
     module=DB

This perlbug was built using Perl 5.18.1 - Fri Sep 27 18:27:33 UTC 2013
It is being executed now by  Perl 5.18.1 - Fri Sep 27 18:20:30 UTC 2013.

Site configuration information for perl 5.18.1:

Configured by abuild at Fri Sep 27 18:20:30 UTC 2013.

Summary of my perl5 (revision 5 version 18 subversion 1) configuration:

   Platform:
     osname=linux, osvers=3.4.6-2.10-xen, archname=x86_64-linux-thread-multi
     uname='linux build16 3.4.6-2.10-xen #1 smp thu jul 26 09:36:26 utc 2012 
(641c197) x86_64 x86_64 x86_64 gnulinux '
     config_args='-ds -e -Dprefix=/usr -Dvendorprefix=/usr -Dinstallusrbinperl 
-Dusethreads -Di_db -Di_dbm -Di_ndbm -Di_gdbm -Dd_dbm_open -Duseshrplib=true 
-Doptimize=-fmessage-length=0 -grecord-gcc-switches -O2 -Wall 
-D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables 
-fasynchronous-unwind-tables -g -Wall -pipe -Accflags=-DPERL_USE_SAFE_PUTENV 
-Dotherlibdirs=/usr/lib/perl5/site_perl 
-Dinc_version_list=5.18.0/x86_64-linux-thread-multi 5.18.0'
     hint=recommended, useposix=true, d_sigaction=define
     useithreads=define, usemultiplicity=define
     useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
     use64bitint=define, use64bitall=define, uselongdouble=undef
     usemymalloc=n, bincompat5005=undef
   Compiler:
     cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DPERL_USE_SAFE_PUTENV 
-fno-strict-aliasing -pipe -fstack-protector -D_LARGEFILE_SOURCE 
-D_FILE_OFFSET_BITS=64',
     optimize='-fmessage-length=0 -grecord-gcc-switches -O2 -Wall 
-D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables 
-fasynchronous-unwind-tables -g -Wall -pipe',
     cppflags='-D_REENTRANT -D_GNU_SOURCE -DPERL_USE_SAFE_PUTENV 
-fno-strict-aliasing -pipe -fstack-protector'
     ccversion='', gccversion='4.8.1 20130909 [gcc-4_8-branch revision 
202388]', 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 =' -L/usr/local/lib64 -fstack-protector'
     libpth=/lib64 /usr/lib64 /usr/local/lib64
     libs=-lm -ldl -lcrypt -lpthread
     perllibs=-lm -ldl -lcrypt -lpthread
     libc=/lib64/libc-2.18.so, so=so, useshrplib=true, libperl=libperl.so
     gnulibc_version='2.18'
   Dynamic Linking:
     dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E 
-Wl,-rpath,/usr/lib/perl5/5.18.1/x86_64-linux-thread-multi/CORE'
     cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib64 
-fstack-protector'

Locally applied patches:



@INC for perl 5.18.1:
     /home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi
     /home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi
     /home/choroba/perl5/lib/perl5
     /home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi
     /home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi
     /home/choroba/perl5/lib/perl5
     /usr/lib/perl5/site_perl/5.18.1/x86_64-linux-thread-multi
     /usr/lib/perl5/site_perl/5.18.1
     /usr/lib/perl5/vendor_perl/5.18.1/x86_64-linux-thread-multi
     /usr/lib/perl5/vendor_perl/5.18.1
     /usr/lib/perl5/5.18.1/x86_64-linux-thread-multi
     /usr/lib/perl5/5.18.1
     /usr/lib/perl5/site_perl
     .


Environment for perl 5.18.1:
     HOME=/home/choroba
     LANG=en_US.UTF-8
     LANGUAGE=en_US.utf8
     LD_LIBRARY_PATH (unset)
     LOGDIR (unset)

PATH=/home/choroba/perl5/bin:/home/choroba/bin:/bin:/sbin:/usr/bin:/usr/local/bin:/usr/games:/usr/X11R6/bin:/opt/gnome/bin:/home/choroba/perl/bin:.

PERL5LIB=/home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi:/home/choroba/perl5/lib/perl5:/home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi:/home/choroba/perl5/lib/perl5:
     PERL_BADLANG (unset)
     PERL_LOCAL_LIB_ROOT=/home/choroba/perl5
     PERL_MB_OPT=--install_base /home/choroba/perl5
     PERL_MM_OPT=INSTALL_BASE=/home/choroba/perl5
     SHELL=/bin/bash

[p5pRT]

From @choroba

perl5db.patch

--- perl5db.pl.backup	2015-01-06 00:35:29.089785377 +0100
+++ perl5db.pl	2015-01-06 00:35:56.181979984 +0100
@@ -6723,24 +6723,24 @@
 
     # We save, change, then restore STDIN and STDOUT to avoid fork() since
     # some non-Unix systems can do system() but have problems with fork().
-    open( SAVEIN,  "<&STDIN" )  || db_warn("Can't save STDIN");
-    open( SAVEOUT, ">&STDOUT" ) || db_warn("Can't save STDOUT");
-    open( STDIN,   "<&IN" )     || db_warn("Can't redirect STDIN");
-    open( STDOUT,  ">&OUT" )    || db_warn("Can't redirect STDOUT");
+    open( SAVEIN,  "<&STDIN" )  || _db_warn("Can't save STDIN");
+    open( SAVEOUT, ">&STDOUT" ) || _db_warn("Can't save STDOUT");
+    open( STDIN,   "<&IN" )     || _db_warn("Can't redirect STDIN");
+    open( STDOUT,  ">&OUT" )    || _db_warn("Can't redirect STDOUT");
 
     # XXX: using csh or tcsh destroys sigint retvals!
     system(@_);
-    open( STDIN,  "<&SAVEIN" )  || db_warn("Can't restore STDIN");
-    open( STDOUT, ">&SAVEOUT" ) || db_warn("Can't restore STDOUT");
+    open( STDIN,  "<&SAVEIN" )  || _db_warn("Can't restore STDIN");
+    open( STDOUT, ">&SAVEOUT" ) || _db_warn("Can't restore STDOUT");
     close(SAVEIN);
     close(SAVEOUT);
 
     # most of the $? crud was coping with broken cshisms
     if ( $? >> 8 ) {
-        db_warn( "(Command exited ", ( $? >> 8 ), ")\n" );
+        _db_warn( "(Command exited ", ( $? >> 8 ), ")\n" );
     }
     elsif ($?) {
-        db_warn(
+        _db_warn(
             "(Command died of SIG#",
             ( $? & 127 ),
             ( ( $? & 128 ) ? " -- core dumped" : "" ),

[p5pRT]

From @jkeenan

On Mon Jan 05 16​:26​:08 2015, choroba@​cpan.org wrote​:

This is a bug report for perl from choroba@​cpan.org,
generated with the help of perlbug 1.39 running under perl 5.18.1.

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

Perl debugger sometimes tries to call a non-existent subroutine
db_warn. It's real name is _db_warn, though.

How to replicate​:

perl -d -e1
!/

Output​:

/bin/bash​: /​: Is a directory
Undefined subroutine &DB​::db_warn called at
/usr/lib/perl5/5.18.1/perl5db.pl line 6740.
at /usr/lib/perl5/5.18.1/perl5db.pl line 6740.
DB​::_db_system('/bin/bash', '-c', '/') called at
/usr/lib/perl5/5.18.1/perl5db.pl line 3923
DB​::Obj​::_handle_sh_command('DB​::Obj=HASH(0x105df48)') called
at /usr/lib/perl5/5.18.1/perl5db.pl line 2992
DB​::DB called at -e line 1

Patch to fix the issue attached.

Choroba

Thank you very much for this report. This is a bug which crept in somewhere between perl 5.16.3 and perl 5.18.2.

#####
[] 11 $ perlbrew switch perl-5.16.3
[] 12 $ perl -d -e1

Loading DB routines from perl5db.pl version 1.37
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main​::(-e​:1)​: 1
  DB<1> !/
No such command!

  DB<1> q
[] 13 $ perlbrew switch perl-5.18.2
[] 14 $ perl -d -e1

Loading DB routines from perl5db.pl version 1.39_10
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

main​::(-e​:1)​: 1
  DB<1> !/
/bin/bash​: /​: Is a directory
Undefined subroutine &DB​::db_warn called at /home/jkeenan/perl5/perlbrew/perls/perl-5.18.2/lib/5.18.2/perl5db.pl line 6735.
at /home/jkeenan/perl5/perlbrew/perls/perl-5.18.2/lib/5.18.2/perl5db.pl line 6735.
  DB​::_db_system('/bin/bash', '-c', '/') called at /home/jkeenan/perl5/perlbrew/perls/perl-5.18.2/lib/5.18.2/perl5db.pl line 3918
  DB​::Obj​::_handle_sh_command('DB​::Obj=HASH(0x1dee6b0)') called at /home/jkeenan/perl5/perlbrew/perls/perl-5.18.2/lib/5.18.2/perl5db.pl line 2987
  DB​::DB called at -e line 1
Debugged program terminated. Use q to quit or R to restart,
use o inhibit_exit to avoid stopping after program termination,
h q, h R or h o to get additional info.
  DB<2> q
#####

We should figure out what commit broke this functionality, then consider whether we should apply your patch or try to restore the previous behavior.

[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags​:
category=library
severity=low
module=DB
---
This perlbug was built using Perl 5.18.1 - Fri Sep 27 18​:27​:33 UTC
2013
It is being executed now by Perl 5.18.1 - Fri Sep 27 18​:20​:30 UTC
2013.

Site configuration information for perl 5.18.1​:

Configured by abuild at Fri Sep 27 18​:20​:30 UTC 2013.

Summary of my perl5 (revision 5 version 18 subversion 1)
configuration​:

Platform​:
osname=linux, osvers=3.4.6-2.10-xen, archname=x86_64-linux-thread-
multi
uname='linux build16 3.4.6-2.10-xen #1 smp thu jul 26 09​:36​:26 utc
2012
(641c197) x86_64 x86_64 x86_64 gnulinux '
config_args='-ds -e -Dprefix=/usr -Dvendorprefix=/usr
-Dinstallusrbinperl
-Dusethreads -Di_db -Di_dbm -Di_ndbm -Di_gdbm -Dd_dbm_open
-Duseshrplib=true
-Doptimize=-fmessage-length=0 -grecord-gcc-switches -O2 -Wall
-D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables
-fasynchronous-unwind-tables -g -Wall -pipe -Accflags=-
DPERL_USE_SAFE_PUTENV
-Dotherlibdirs=/usr/lib/perl5/site_perl
-Dinc_version_list=5.18.0/x86_64-linux-thread-multi 5.18.0'
hint=recommended, useposix=true, d_sigaction=define
useithreads=define, usemultiplicity=define
useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
use64bitint=define, use64bitall=define, uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler​:
cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE
-DPERL_USE_SAFE_PUTENV
-fno-strict-aliasing -pipe -fstack-protector -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64',
optimize='-fmessage-length=0 -grecord-gcc-switches -O2 -Wall
-D_FORTIFY_SOURCE=2 -fstack-protector -funwind-tables
-fasynchronous-unwind-tables -g -Wall -pipe',
cppflags='-D_REENTRANT -D_GNU_SOURCE -DPERL_USE_SAFE_PUTENV
-fno-strict-aliasing -pipe -fstack-protector'
ccversion='', gccversion='4.8.1 20130909 [gcc-4_8-branch revision
202388]', 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 =' -L/usr/local/lib64 -fstack-protector'
libpth=/lib64 /usr/lib64 /usr/local/lib64
libs=-lm -ldl -lcrypt -lpthread
perllibs=-lm -ldl -lcrypt -lpthread
libc=/lib64/libc-2.18.so, so=so, useshrplib=true, libperl=libperl.so
gnulibc_version='2.18'
Dynamic Linking​:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E
-Wl,-rpath,/usr/lib/perl5/5.18.1/x86_64-linux-thread-multi/CORE'
cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib64
-fstack-protector'

Locally applied patches​:

---
@​INC for perl 5.18.1​:
/home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi
/home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi
/home/choroba/perl5/lib/perl5
/home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi
/home/choroba/perl5/lib/perl5/x86_64-linux-thread-multi
/home/choroba/perl5/lib/perl5
/usr/lib/perl5/site_perl/5.18.1/x86_64-linux-thread-multi
/usr/lib/perl5/site_perl/5.18.1
/usr/lib/perl5/vendor_perl/5.18.1/x86_64-linux-thread-multi
/usr/lib/perl5/vendor_perl/5.18.1
/usr/lib/perl5/5.18.1/x86_64-linux-thread-multi
/usr/lib/perl5/5.18.1
/usr/lib/perl5/site_perl
.

---
Environment for perl 5.18.1​:
HOME=/home/choroba
LANG=en_US.UTF-8
LANGUAGE=en_US.utf8
LD_LIBRARY_PATH (unset)
LOGDIR (unset)

PATH=/home/choroba/perl5/bin​:/home/choroba/bin​:/bin​:/sbin​:/usr/bin​:/usr/local/bin​:/usr/games​:/usr/X11R6/bin​:/opt/gnome/bin​:/home/choroba/perl/bin​:.

PERL5LIB=/home/choroba/perl5/lib/perl5/x86_64-linux-thread-
multi​:/home/choroba/perl5/lib/perl5​:/home/choroba/perl5/lib/perl5/x86_64-
linux-thread-multi​:/home/choroba/perl5/lib/perl5​:
PERL_BADLANG (unset)
PERL_LOCAL_LIB_ROOT=/home/choroba/perl5
PERL_MB_OPT=--install_base /home/choroba/perl5
PERL_MM_OPT=INSTALL_BASE=/home/choroba/perl5
SHELL=/bin/bash

--
James E Keenan (jkeenan@​cpan.org)

[p5pRT]

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

[p5pRT]

From @cpansprout

On Mon Jan 05 18​:51​:14 2015, jkeenan wrote​:

We should figure out what commit broke this functionality, then
consider whether we should apply your patch or try to restore the
previous behavior.

b5679dc clearly had a few typos in it. That 5.16 had no ! command is unrelated.

On Mon Jan 05 16​:26​:08 2015, choroba@​cpan.org wrote​:

Patch to fix the issue attached.

Thank you. Applied as 2384afe.

--

Father Chrysostomos

[p5pRT]

@cpansprout - Status changed from 'open' to 'pending release'

[p5pRT]

From @khwilliamson

Thanks for submitting this ticket

The issue should be resolved with the release today of Perl v5.22, available at http​://www.perl.org/get.html
If you find that the problem persists, feel free to reopen this ticket

--
Karl Williamson for the Perl 5 porters team

[p5pRT]

@khwilliamson - Status changed from 'pending release' to 'resolved'