search

Perl / perl5

🐪 The Perl programming language
https://dev.perl.org/perl5/
Other
1.98k stars 559 forks source link

Devel::Peek: Indentation gap when dumping MG object #16380

Open p5pRT opened 6 years ago

p5pRT commented 6 years ago

Migrated from rt.perl.org#132764 (status was 'open')

Searchable as RT132764$

p5pRT commented 6 years ago

From @KES777

Created by @KES777

Depending on the PL_dumpindent the MG_OBJ details are dumped with indentation gap​:

Look at output​:

PL_dumpindent = 1; SV = PVMG(0x1d74a70) at 0x1bba790   REFCNT = 1   FLAGS = (GMG\,SMG\,RMG)   IV = 0   NV = 0   PV = 0   MAGIC = 0x1bb3bd0   MG_VIRTUAL = &PL_vtbl_packelem   MG_TYPE = PERL_MAGIC_tiedscalar(q)   MG_FLAGS = 0x02   REFCOUNTED   MG_OBJ = 0x1baffe8   SV = IV(0x1baffd8) at 0x1baffe8 ^^   REFCNT = 1   FLAGS = (ROK)   RV = 0x1c778b8   SV = PVHV(0x1ba1c60) at 0x1c778b8   ^^ ...

PL_dumpindent = 2; SV = PVMG(0x21aa9d0) at 0x1ff0790   REFCNT = 1   FLAGS = (GMG\,SMG\,RMG)   IV = 0   NV = 0   PV = 0   MAGIC = 0x1fe9b90   MG_VIRTUAL = &PL_vtbl_packelem   MG_TYPE = PERL_MAGIC_tiedscalar(q)   MG_FLAGS = 0x02   REFCOUNTED   MG_OBJ = 0x1fe5fe8   SV = IV(0x1fe5fd8) at 0x1fe5fe8   ^^   REFCNT = 1   FLAGS = (ROK)   RV = 0x21a90e8   SV = PVHV(0x1fd7c60) at 0x21a90e8   ^^ ...

PL_dumpindent = 3; SV = PVMG(0x15999c0) at 0x13df790   REFCNT = 1   FLAGS = (GMG\,SMG\,RMG)   IV = 0   NV = 0   PV = 0   MAGIC = 0x13d8b90   MG_VIRTUAL = &PL_vtbl_packelem   MG_TYPE = PERL_MAGIC_tiedscalar(q)   MG_FLAGS = 0x02   REFCOUNTED   MG_OBJ = 0x13d4fe8   SV = IV(0x13d4fd8) at 0x13d4fe8   ^^   REFCNT = 1   FLAGS = (ROK)   RV = 0x16c8098   SV = PVHV(0x13c6c60) at 0x16c8098   ^^

So this is unclear where SV belons to Is it belongs to MAGIC or MG_OBJ?

There is no any documentation about PL_dumpindent

Perl Info ``` Flags: category=core severity=low Site configuration information for perl 5.24.0: Configured by kes at Wed Oct 19 14:07:47 EEST 2016. Summary of my perl5 (revision 5 version 24 subversion 0) configuration: Platform: osname=linux, osvers=4.4.0-43-generic, archname=x86_64-linux uname='linux work 4.4.0-43-generic #63-ubuntu smp wed oct 12 13:48:03 utc 2016 x86_64 x86_64 x86_64 gnulinux ' config_args='-de -Dprefix=/home/kes/perl5/perlbrew/perls/perl-5.24.0 -Aeval:scriptdir=/home/kes/perl5/perlbrew/perls/perl-5.24.0/bin' hint=recommended, useposix=true, d_sigaction=define useithreads=undef, usemultiplicity=undef use64bitint=define, use64bitall=define, uselongdouble=undef usemymalloc=n, bincompat5005=undef Compiler: cc='cc', ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', optimize='-O2', cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include' ccversion='', gccversion='5.4.0 20160609', 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/gcc/x86_64-linux-gnu/5/include-fixed /usr/include/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /lib64 /usr/lib64 libs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc libc=libc-2.23.so, so=so, useshrplib=false, libperl=libperl.a gnulibc_version='2.23' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E' cccdlflags='-fPIC', lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector-strong' Locally applied patches: Devel::PatchPerl 1.38 @INC for perl 5.24.0: /home/kes/perl5/perlbrew/perls/perl-5.24.0/lib/site_perl/5.24.0/x86_64-linux /home/kes/perl5/perlbrew/perls/perl-5.24.0/lib/site_perl/5.24.0 /home/kes/perl5/perlbrew/perls/perl-5.24.0/lib/5.24.0/x86_64-linux /home/kes/perl5/perlbrew/perls/perl-5.24.0/lib/5.24.0 . Environment for perl 5.24.0: HOME=/home/kes LANG=en_US.UTF-8 LANGUAGE=en LC_ADDRESS=uk_UA.UTF-8 LC_IDENTIFICATION=uk_UA.UTF-8 LC_MEASUREMENT=uk_UA.UTF-8 LC_MESSAGES=en_US.UTF-8 LC_MONETARY=uk_UA.UTF-8 LC_NAME=uk_UA.UTF-8 LC_NUMERIC=uk_UA.UTF-8 LC_PAPER=uk_UA.UTF-8 LC_TELEPHONE=uk_UA.UTF-8 LD_LIBRARY_PATH (unset) LOGDIR (unset) PATH=/home/kes/perl5/perlbrew/bin:/home/kes/perl5/perlbrew/perls/perl-5.24.0/bin:/home/kes/bin:/home/kes/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games PERLBREW=command perlbrew PERLBREW_BASHRC_VERSION=0.78 PERLBREW_HOME=/home/kes/.perlbrew PERLBREW_MANPATH=/home/kes/perl5/perlbrew/perls/perl-5.24.0/man PERLBREW_PATH=/home/kes/perl5/perlbrew/bin:/home/kes/perl5/perlbrew/perls/perl-5.24.0/bin PERLBREW_PERL=perl-5.24.0 PERLBREW_ROOT=/home/kes/perl5/perlbrew PERLBREW_VERSION=0.78 PERL_BADLANG (unset) SHELL=/bin/bash ```
p5pRT commented 6 years ago

From @KES777

Another example of ambiguity​: SV = IV(0x2598d20) at 0x2598d30   REFCNT = 1   FLAGS = (TEMP\,ROK)   RV = 0x25a3840   SV = PVCV(0x2597c28) at 0x25a3840   REFCNT = 3   FLAGS = ()   COMP_STASH = 0x2583ff8 "main"   START = 0x25aae40 ===> 1   ROOT = 0x27842f0   GVGV​::GV = 0x25a3660 "main" :​: "t"   FILE = "/home/kes/tmp/t3.pl"   DEPTH = 1   FLAGS = 0x0   OUTSIDE_SEQ = 2000   PADLIST = 0x2774220   PADNAME = 0x27d2970(0x27e0410) PAD = 0x25a36c0(0x26ba700)   3. 0x2743170\<1> (2001\,2002) "$x"   OUTSIDE = 0x25843d0 (MAIN)

Here we can think that PADNAME is member of PVCV. But from the next out we can understand that PADNAME is child for PADLIST​: SV = PVCV(0x2597c28) at 0x25a3840   REFCNT = 2   FLAGS = ()   COMP_STASH = 0x2583ff8 "main"   START = 0x25aae40 ===> 1   ROOT = 0x27842f0   GVGV​::GV = 0x25a3660 "main" :​: "t"   FILE = "/home/kes/tmp/t3.pl"   DEPTH = 1   FLAGS = 0x0   OUTSIDE_SEQ = 2000   PADLIST = 0x2774220   PADNAME = 0x27d2970(0x27e0410) PAD = 0x25a36c0(0x26ba700)   3. 0x2743170\<1> (2001\,2002) "$x"   OUTSIDE = 0x25843d0 (MAIN)

p5pRT commented 6 years ago

From @KES777

Also there are different defaults for PL_dumpindent when dumping from perl script and from XS

p5pRT commented 6 years ago

From @jkeenan

On Thu\, 25 Jan 2018 11​:16​:40 GMT\, kes-kes@​yandex.ru wrote​:

Message-Id​: \5\.24\.0\_11686\_1516878441@&#8203;work To​: perlbug@​perl.org Reply-To​: kes-kes@​yandex.ru Cc​: kes-kes@​yandex.ru From​: kes-kes@​yandex.ru Subject​: Devel​::Peek​: Indentation gap when dumping MG object

This is a bug report for perl from kes-kes@​yandex.ru\, generated with the help of perlbug 1.40 running under perl 5.24.0.

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

Depending on the PL_dumpindent the MG_OBJ details are dumped with indentation gap​:

Look at output​:

PL_dumpindent = 1; SV = PVMG(0x1d74a70) at 0x1bba790 REFCNT = 1 FLAGS = (GMG\,SMG\,RMG) IV = 0 NV = 0 PV = 0 MAGIC = 0x1bb3bd0 MG_VIRTUAL = &PL_vtbl_packelem MG_TYPE = PERL_MAGIC_tiedscalar(q) MG_FLAGS = 0x02 REFCOUNTED MG_OBJ = 0x1baffe8 SV = IV(0x1baffd8) at 0x1baffe8 ^^ REFCNT = 1 FLAGS = (ROK) RV = 0x1c778b8 SV = PVHV(0x1ba1c60) at 0x1c778b8 ^^ ...

PL_dumpindent = 2; SV = PVMG(0x21aa9d0) at 0x1ff0790 REFCNT = 1 FLAGS = (GMG\,SMG\,RMG) IV = 0 NV = 0 PV = 0 MAGIC = 0x1fe9b90 MG_VIRTUAL = &PL_vtbl_packelem MG_TYPE = PERL_MAGIC_tiedscalar(q) MG_FLAGS = 0x02 REFCOUNTED MG_OBJ = 0x1fe5fe8 SV = IV(0x1fe5fd8) at 0x1fe5fe8 ^^ REFCNT = 1 FLAGS = (ROK) RV = 0x21a90e8 SV = PVHV(0x1fd7c60) at 0x21a90e8 ^^ ...

PL_dumpindent = 3; SV = PVMG(0x15999c0) at 0x13df790 REFCNT = 1 FLAGS = (GMG\,SMG\,RMG) IV = 0 NV = 0 PV = 0 MAGIC = 0x13d8b90 MG_VIRTUAL = &PL_vtbl_packelem MG_TYPE = PERL_MAGIC_tiedscalar(q) MG_FLAGS = 0x02 REFCOUNTED MG_OBJ = 0x13d4fe8 SV = IV(0x13d4fd8) at 0x13d4fe8 ^^ REFCNT = 1 FLAGS = (ROK) RV = 0x16c8098 SV = PVHV(0x13c6c60) at 0x16c8098 ^^

Would you be able to provide a short program which a programmer not fluent in XS could run in order to become familiar with this problem. (It's not clear what you did to generate the sample above.)

So this is unclear where SV belons to Is it belongs to MAGIC or MG_OBJ?

There is no any documentation about PL_dumpindent

Confirmed -- but if it's an implementation detail internal to Peek.xs we probably don't want to formally document it. The POD in Peek.pm takes a very cautious approach​: 'This document will take a passive\, and safe\, approach to data debugging and for that it will describe only the "Dump()" function.'

Thank you very much.

-- James E Keenan (jkeenan@​cpan.org)

p5pRT commented 6 years ago

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

p5pRT commented 6 years ago

From @KES777

The Devel​::Peek makes use of undocumented perlapi function​: do_sv_dump

https://metacpan.org/source/XSAWYERX/perl-5.28.0/ext/Devel-Peek/Peek.xs#L337 https://perldoc.perl.org/perlapi.html#do_sv_dump

The issue is about formatting​:

  PADLIST = 0x2774220   PADNAME = 0x27d2970(0x27e0410) PAD = 0x25a36c0(0x26ba700)

VS

  PADLIST = 0x2774220   PADNAME = 0x27d2970(0x27e0410) PAD = 0x25a36c0(0x26ba700)

From the output I can not say that PADNAME is member of PADLIST

See an example​: https://metacpan.org/pod/Devel::Peek#A-reference-to-a-subroutine

This undocumented function has configuration for the indentation. And this **configuration is applied only to curtain lines** of output. Which lead to confusion.

p5pRT commented 6 years ago

From @jkeenan

On Tue\, 04 Sep 2018 08​:09​:34 GMT\, kes-kes@​yandex.ru wrote​:

The Devel​::Peek makes use of undocumented perlapi function​: do_sv_dump

https://metacpan.org/source/XSAWYERX/perl-5.28.0/ext/Devel- Peek/Peek.xs#L337 https://perldoc.perl.org/perlapi.html#do_sv_dump

The issue is about formatting​:

PADLIST = 0x2774220 PADNAME = 0x27d2970(0x27e0410) PAD = 0x25a36c0(0x26ba700)

VS

PADLIST = 0x2774220 PADNAME = 0x27d2970(0x27e0410) PAD = 0x25a36c0(0x26ba700)

From the output I can not say that PADNAME is member of PADLIST

See an example​: https://metacpan.org/pod/Devel::Peek#A-reference-to-a- subroutine

This undocumented function has configuration for the indentation. And this **configuration is applied only to curtain lines** of output. Which lead to confusion.

Please find attached a small program\, '132764-devel-peek.pl'\, which Dump-s a reference to a subroutine using a sub name drawn from the Devel​::Peek documentation. When I run it (perl-5.28.0)\, I get the output attached as '132764.top_targets.output.txt'.

How would I re-write sub MY​::top_targets to make it complicated enough to display the ambiguous indentation you just described?

Thank you very much. -- James E Keenan (jkeenan@​cpan.org)

p5pRT commented 6 years ago

From @jkeenan

132764-devel-peek.pl

p5pRT commented 6 years ago

From @jkeenan

SV = IV(0x25e0568) at 0x25e0578   REFCNT = 1   FLAGS = (TEMP\,ROK)   RV = 0x2606fb0   SV = PVCV(0x25fd4b8) at 0x2606fb0   REFCNT = 2   FLAGS = ()   COMP_STASH = 0x25e03f8 "main"   START = 0x2615070 ===> 1   ROOT = 0x2626918   GVGV​::GV = 0x2606fe0 "MY" :​: "top_targets"   FILE = "132764-devel-peek.pl"   DEPTH = 0   FLAGS = 0x0   OUTSIDE_SEQ = 389   PADLIST = 0x26110b0   PADNAME = 0x2615b50(0x26835c0) PAD = 0x2606ed8(0x26334f0)   OUTSIDE = 0x25e0728 (MAIN)

p5pRT commented 6 years ago

From @KES777

How would I re-write sub MY​::top_targets to make it complicated enough to display the ambiguous indentation you just described?

Actually your dump is already ambigious​:

  PADNAME is a member of PADLIST\, not the `SV = PVCV(0x25fd4b8) at 0x2606fb0`

Play with this value​:

PL_dumpindent = 3;

I change your script and attach the XS

p5pRT commented 6 years ago

From @KES777

132764-devel-peek.pl

p5pRT commented 6 years ago

From @KES777

dump.xs

p5pRT commented 6 years ago

From @tonycoz

On Tue\, 04 Sep 2018 08​:01​:39 -0700\, jkeenan wrote​:

How would I re-write sub MY​::top_targets to make it complicated enough to display the ambiguous indentation you just described?

The attached patch against blead might make this easier to demonstrate.

$ ./perl -Ilib -MDevel​::Peek -e '$Devel​::Peek​::dumpindent = 2; Dump(\$!)' SV = IV(0x55ffb73264f8) at 0x55ffb7326508   REFCNT = 1   FLAGS = (TEMP\,ROK)   RV = 0x55ffb7348a88   SV = PVMG(0x55ffb73783c0) at 0x55ffb7348a88   REFCNT = 2   FLAGS = (GMG\,SMG)   IV = 0   NV = 0   PV = 0   MAGIC = 0x55ffb734c820   MG_VIRTUAL = &PL_vtbl_sv   MG_TYPE = PERL_MAGIC_sv(\0)   MG_OBJ = 0x55ffb7326610   MG_LEN = 1   MG_PTR = 0x55ffb73685c0 "!" $ ./perl -Ilib -MDevel​::Peek -e '$Devel​::Peek​::dumpindent = 1; Dump(\$!)' SV = IV(0x55d9bf3cb4f8) at 0x55d9bf3cb508   REFCNT = 1   FLAGS = (TEMP\,ROK)   RV = 0x55d9bf3eda88 SV = PVMG(0x55d9bf41d3d0) at 0x55d9bf3eda88   REFCNT = 2   FLAGS = (GMG\,SMG)   IV = 0   NV = 0   PV = 0   MAGIC = 0x55d9bf3f5220   MG_VIRTUAL = &PL_vtbl_sv   MG_TYPE = PERL_MAGIC_sv(\0)   MG_OBJ = 0x55d9bf3cb610   MG_LEN = 1   MG_PTR = 0x55d9bf423bf0 "!"

Tony

p5pRT commented 6 years ago

From @tonycoz

0001-perl-132764-provide-control-over-Dump-s-indent-level.patch ```diff From f4e7b27e04a51b46154f733b7e06c8c7f9d1bfe6 Mon Sep 17 00:00:00 2001 From: Tony Cook Date: Thu, 6 Sep 2018 10:32:52 +1000 Subject: (perl #132764) provide control over Dump()s indent level Mostly intended for easily demonstrating the issue in #132764. Needs tests/docs before it's merged to blead. --- ext/Devel-Peek/Peek.pm | 2 ++ ext/Devel-Peek/Peek.xs | 6 ++++-- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/ext/Devel-Peek/Peek.pm b/ext/Devel-Peek/Peek.pm index 3d790e763a..0c9499b44e 100644 --- a/ext/Devel-Peek/Peek.pm +++ b/ext/Devel-Peek/Peek.pm @@ -18,6 +18,8 @@ require XSLoader; XSLoader::load(); +our $dump_indent = 2; + sub import { my $c = shift; my $ops_rx = qr/^:opd(=[stP]*)?\b/; diff --git a/ext/Devel-Peek/Peek.xs b/ext/Devel-Peek/Peek.xs index 8a8c0b96d7..9550ca4a8e 100644 --- a/ext/Devel-Peek/Peek.xs +++ b/ext/Devel-Peek/Peek.xs @@ -333,7 +333,8 @@ S_do_dump(pTHX_ SV *const sv, I32 lim) const STRLEN pv_lim = pv_lim_sv ? SvIV(pv_lim_sv) : 0; SV *dumpop = perl_get_sv("Devel::Peek::dump_ops", 0); const U16 save_dumpindent = PL_dumpindent; - PL_dumpindent = 2; + SV *dumpindent_sv = perl_get_sv("Devel::Peek::dumpindent", 0); + PL_dumpindent = dumpindent_sv ? SvIV(dumpindent_sv) : 2; do_sv_dump(0, Perl_debug_log, sv, 0, lim, (bool)(dumpop && SvTRUE(dumpop)), pv_lim); PL_dumpindent = save_dumpindent; @@ -458,7 +459,8 @@ PPCODE: const STRLEN pv_lim = pv_lim_sv ? SvIV(pv_lim_sv) : 0; SV *dumpop = perl_get_sv("Devel::Peek::dump_ops", 0); const U16 save_dumpindent = PL_dumpindent; - PL_dumpindent = 2; + SV *dumpindent_sv = perl_get_sv("Devel::Peek::dumpindent", 0); + PL_dumpindent = dumpindent_sv ? SvIV(dumpindent_sv) : 2; for (i=1; i