From @craigberry

Something fairly recent as of v5.27.7-130-g4d7e83bba2 broke the "x" command in the debugger. From within t/ after a successful build​:

$ ./perl -d -I../lib io/fs.t

Loading DB routines from perl5db.pl version 1.53
Editor support available.

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

main​::(io/fs.t​:11)​: my $Is_VMSish = ($^O eq 'VMS');
DB<1> b 195
DB<2> c
1..61
ok 1 - umask
ok 2 - link a b
ok 3 - link b c
ok 4 - link count of triply-linked file
ok 5 - mode of triply-linked file
ok 6 - chmod succeeding
ok 7 - chmod going through
ok 8 - chmod two files
ok 9 - chmod going through to c
ok 10 - chmod going through to x
ok 11 - unlink two files
ok 12 - ino of removed file b should be undef
ok 13 - ino of removed file x should be undef
ok 14 - open a
ok 15 - fchmod
main​::(io/fs.t​:195)​: is($mode & 0777, 0, "perm reset");
DB<2> x $mode
Died at ../lib/perl5db.pl line 6390.
at ../lib/perl5db.pl line 6390.
  DB​::dumpit(GLOB(0x7fca31182bf0), ARRAY(0x7fca312ba2a0)) called at ../lib/perl5db.pl line 767
  DB​::eval called at ../lib/perl5db.pl line 3138
  DB​::DB called at io/fs.t line 195
# Looks like you planned 61 tests but ran 15.
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<3>

$ ./perl -I../lib -V
Summary of my perl5 (revision 5 version 27 subversion 8) configuration​:
Commit id​: 4d7e83b
Platform​:
  osname=darwin
  osvers=17.3.0
  archname=darwin-2level
  uname='darwin triamond.local 17.3.0 darwin kernel version 17.3.0​: thu nov 9 18​:09​:22 pst 2017; root​:xnu-4570.31.3~1release_x86_64 x86_64 '
  config_args='-Dusedevel -des'
  hint=recommended
  useposix=true
  d_sigaction=define
  useithreads=undef
  usemultiplicity=undef
  use64bitint=define
  use64bitall=define
  uselongdouble=undef
  usemymalloc=n
  default_inc_excludes_dot=define
  bincompat5005=undef
Compiler​:
  cc='cc'
  ccflags ='-fno-common -DPERL_DARWIN -mmacosx-version-min=10.13 -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -I/opt/local/include -DPERL_USE_SAFE_PUTENV'
  optimize='-O3'
  cppflags='-fno-common -DPERL_DARWIN -mmacosx-version-min=10.13 -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -I/opt/local/include'
  ccversion=''
  gccversion='4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)'
  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 =' -mmacosx-version-min=10.13 -fstack-protector-strong -L/usr/local/lib'
  libpth=/usr/local/lib /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/9.0.0/lib /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk/usr/lib /usr/lib
  libs=-lpthread -ldbm -ldl -lm -lutil -lc
  perllibs=-lpthread -ldl -lm -lutil -lc
  libc=
  so=dylib
  useshrplib=false
  libperl=libperl.a
  gnulibc_version=''
Dynamic Linking​:
  dlsrc=dl_dlopen.xs
  dlext=bundle
  d_dlsymun=undef
  ccdlflags=' '
  cccdlflags=' '
  lddlflags=' -mmacosx-version-min=10.13 -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector-strong'

Characteristics of this binary (from libperl)​:
Compile-time options​:
  HAS_TIMES
  PERLIO_LAYERS
  PERL_COPY_ON_WRITE
  PERL_DONT_CREATE_GVSV
  PERL_MALLOC_WRAP
  PERL_OP_PARENT
  PERL_PRESERVE_IVUV
  PERL_USE_DEVEL
  PERL_USE_SAFE_PUTENV
  USE_64_BIT_ALL
  USE_64_BIT_INT
  USE_LARGE_FILES
  USE_LOCALE
  USE_LOCALE_COLLATE
  USE_LOCALE_CTYPE
  USE_LOCALE_NUMERIC
  USE_LOCALE_TIME
  USE_PERLIO
  USE_PERL_ATOF
Built under darwin
Compiled at Jan 12 2018 17​:47​:17
@​INC​:
  ../lib
  /usr/local/lib/perl5/site_perl/5.27.8/darwin-2level
  /usr/local/lib/perl5/site_perl/5.27.8
  /usr/local/lib/perl5/5.27.8/darwin-2level
  /usr/local/lib/perl5/5.27.8
  /usr/local/lib/perl5/site_perl

From @craigberry

On Fri, Jan 12, 2018 at 10​:08 PM, Craig A.Berry
<perlbug-followup@​perl.org> wrote​:

# New Ticket Created by Craig A. Berry
# Please include the string​: [perl #132715]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=132715 >

Something fairly recent as of v5.27.7-130-g4d7e83bba2 broke the "x" command in the debugger. From within t/ after a successful build​:

It's not actually that recent. I've reproduced it in v5.27.5.

$ ./perl -d -I../lib io/fs.t

Loading DB routines from perl5db.pl version 1.53
Editor support available.

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

main​::(io/fs.t​:11)​: my $Is_VMSish = ($^O eq 'VMS');
DB<1> b 195
DB<2> c
1..61
<snip>
main​::(io/fs.t​:195)​: is($mode & 0777, 0, "perm reset");
DB<2> x $mode
Died at ../lib/perl5db.pl line 6390.
at ../lib/perl5db.pl line 6390.
DB​::dumpit(GLOB(0x7fca31182bf0), ARRAY(0x7fca312ba2a0)) called at ../lib/perl5db.pl line 767
DB​::eval called at ../lib/perl5db.pl line 3138
DB​::DB called at io/fs.t line 195
# Looks like you planned 61 tests but ran 15.

The code in perl5db.pl that looks like this is failing​:

  # Load dumpvar.pl unless we've already got the sub we need from it.
  unless ( defined &main​::dumpValue ) {
  do 'dumpvar.pl' or die $@​;
  }

The current working directory is t/<some temp directory> and @​INC
consists only of C<../lib>, so it can't find dumpvar.pl. An installed
perl would likely not have this problem as the @​INC entries would be
absolute paths, but debugging test failures in a core build is a
pretty key feature.

I don't know why the debugger defers the loading of dumpvar.pl rather
than just requiring it up top. Surely there would be few debug
sessions that never dump a variable?

One approach to fix this might be a self locator as was done for
loc_tools.pl in​:

<https://perl5.git.perl.org/perl.git/commitdiff/9969000e1134387c0ed173e5d1b3f3b760a1d00c>

However, that uses File​::Spec, which perl5db.pl does not currently
use, and there may be a reason for that. The debugger does use Cwd
and saves the variable C<$_initial_cwd>, but knowing what directory we
started in doesn't really help us unless we combine it with each entry
in @​INC (and only when those entries are relative).

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

From @jkeenan

On Sat, 13 Jan 2018 18​:18​:37 GMT, craig.a.berry@​gmail.com wrote​:

On Fri, Jan 12, 2018 at 10​:08 PM, Craig A.Berry
<perlbug-followup@​perl.org> wrote​:

# New Ticket Created by Craig A. Berry
# Please include the string​: [perl #132715]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=132715 >

Something fairly recent as of v5.27.7-130-g4d7e83bba2 broke the "x"
command in the debugger. From within t/ after a successful build​:

It's not actually that recent. I've reproduced it in v5.27.5.

$ ./perl -d -I../lib io/fs.t

Loading DB routines from perl5db.pl version 1.53
Editor support available.

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

main​::(io/fs.t​:11)​: my $Is_VMSish = ($^O eq 'VMS');
DB<1> b 195
DB<2> c
1..61
<snip>
main​::(io/fs.t​:195)​: is($mode & 0777, 0, "perm reset");
DB<2> x $mode
Died at ../lib/perl5db.pl line 6390.
at ../lib/perl5db.pl line 6390.
DB​::dumpit(GLOB(0x7fca31182bf0), ARRAY(0x7fca312ba2a0))
called at ../lib/perl5db.pl line 767
DB​::eval called at ../lib/perl5db.pl line 3138
DB​::DB called at io/fs.t line 195
# Looks like you planned 61 tests but ran 15.

I encountered this myself several weeks ago, but wrote it off as my own clumsiness in using the debugger.

It's very old. I started to do git checkouts of tags and got as far back as this​:

#####
tag v5.15.0
$ git show --format=fuller | head -5
commit 00b4043
Author​: David Golden <dagolden@​cpan.org>
AuthorDate​: Mon Jun 20 19​:07​:28 2011 -0400
Commit​: David Golden <dagolden@​cpan.org>
CommitDate​: Mon Jun 20 19​:07​:28 2011 -0400
#####
[t] 522 $ ./perl -I../lib -d io/fs.t

Loading DB routines from perl5db.pl version 1.34
Editor support available.

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

main​::(io/fs.t​:11)​: my $Is_VMSish = ($^O eq 'VMS');
  DB<1> b 178
  DB<2> c
1..51
ok 1 - umask
ok 2 - link a b
ok 3 - link b c
ok 4 - link count of triply-linked file
ok 5 - mode of triply-linked file
ok 6 - chmod succeeding
ok 7 - chmod going through
ok 8 - chmod two files
ok 9 - chmod going through to c
ok 10 - chmod going through to x
ok 11 - unlink two files
ok 12 - ino of removed file b should be undef
ok 13 - ino of removed file x should be undef
ok 14 - open a
ok 15 - fchmod
main​::(io/fs.t​:178)​: skip "no mode checks", 1 if $skip_mode_checks;
  DB<2> x $mode
Died at ../lib/perl5db.pl line 5619.
at ../lib/perl5db.pl line 5619
  DB​::dumpit('GLOB(0x11d5ce0)', 'ARRAY(0x169f028)') called at ../lib/perl5db.pl line 675
  DB​::eval called at ../lib/perl5db.pl line 3442
  DB​::DB called at io/fs.t line 178
# Looks like you planned 51 tests but ran 15.
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.
#####

The code in perl5db.pl that looks like this is failing​:

# Load dumpvar.pl unless we've already got the sub we need from it.
unless ( defined &main​::dumpValue ) {
do 'dumpvar.pl' or die $@​;
}

The current working directory is t/<some temp directory> and @​INC
consists only of C<../lib>, so it can't find dumpvar.pl. An installed
perl would likely not have this problem as the @​INC entries would be
absolute paths, but debugging test failures in a core build is a
pretty key feature.

I don't know why the debugger defers the loading of dumpvar.pl rather
than just requiring it up top. Surely there would be few debug
sessions that never dump a variable?

One approach to fix this might be a self locator as was done for
loc_tools.pl in​:

<https://perl5.git.perl.org/perl.git/commitdiff/9969000e1134387c0ed173e5d1b3f3b760a1d00c>

However, that uses File​::Spec, which perl5db.pl does not currently
use, and there may be a reason for that. The debugger does use Cwd
and saves the variable C<$_initial_cwd>, but knowing what directory we
started in doesn't really help us unless we combine it with each entry
in @​INC (and only when those entries are relative).

--
James E Keenan (jkeenan@​cpan.org)