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Deparsed object constants lose blessedness #16061

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p5pRT opened this issue Jul 2, 2017 · 5 comments
Open

Deparsed object constants lose blessedness #16061

p5pRT opened this issue Jul 2, 2017 · 5 comments

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@p5pRT
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p5pRT commented Jul 2, 2017

Migrated from rt.perl.org#131687 (status was 'open')

Searchable as RT131687$

@p5pRT
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p5pRT commented Jul 2, 2017

From @mauke

Created by @mauke

$ perl -e 'use constant OBJ => bless {}; print OBJ->isa("main"), "\n"'
1

$ perl -MO=Deparse -e 'use constant OBJ => bless {}; print OBJ->isa("main"), "\n"'
use constant ('OBJ', bless({}));
print {}->isa('main'), "\n";
-e syntax OK

$ perl -MO=Deparse -e 'use constant OBJ => bless {}; print OBJ->isa("main"), "\n"' | perl
-e syntax OK
Can't call method "isa" on unblessed reference at - line 2.

OBJ is deparsed as {} instead of bless({}, 'main'), which breaks the code.

Perl Info

Flags:
    category=library
    severity=low
    module=B::Deparse

Site configuration information for perl 5.26.0:

Configured by mauke at Tue May 30 23:06:36 CEST 2017.

Summary of my perl5 (revision 5 version 26 subversion 0) configuration:
   
  Platform:
    osname=linux
    osvers=4.10.11-1-arch
    archname=i686-linux
    uname='linux simplicio 4.10.11-1-arch #1 smp preempt tue apr 18 09:00:04 cest 2017 i686 gnulinux '
    config_args=''
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=undef
    usemultiplicity=undef
    use64bitint=undef
    use64bitall=undef
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
    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 -march=native'
    cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
    ccversion=''
    gccversion='7.1.1 20170516'
    gccosandvers=''
    intsize=4
    longsize=4
    ptrsize=4
    doublesize=8
    byteorder=1234
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=12
    longdblkind=3
    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-strong -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib/gcc/i686-pc-linux-gnu/7.1.1/include-fixed /usr/lib /lib
    libs=-lpthread -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc -lgdbm_compat
    perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    libc=libc-2.25.so
    so=so
    useshrplib=false
    libperl=libperl.a
    gnulibc_version='2.25'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=so
    d_dlsymun=undef
    ccdlflags='-Wl,-E'
    cccdlflags='-fPIC'
    lddlflags='-shared -O2 -march=native -L/usr/local/lib -fstack-protector-strong'



@INC for perl 5.26.0:
    /home/mauke/usr/lib/perl5/site_perl/5.26.0/i686-linux
    /home/mauke/usr/lib/perl5/site_perl/5.26.0
    /home/mauke/usr/lib/perl5/5.26.0/i686-linux
    /home/mauke/usr/lib/perl5/5.26.0


Environment for perl 5.26.0:
    HOME=/home/mauke
    LANG=en_US.UTF-8
    LANGUAGE=en_US
    LC_COLLATE=C
    LC_MONETARY=de_DE.UTF-8
    LC_TIME=de_DE.UTF-8
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/mauke/perl5/perlbrew/bin:/home/mauke/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl
    PERLBREW_BASHRC_VERSION=0.73
    PERLBREW_HOME=/home/mauke/.perlbrew
    PERLBREW_ROOT=/home/mauke/perl5/perlbrew
    PERL_BADLANG (unset)
    PERL_UNICODE=SAL
    SHELL=/bin/bash

@p5pRT
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p5pRT commented Jul 2, 2017

From zefram@fysh.org

l.mai@​web.de wrote​:

OBJ is deparsed as {} instead of bless({}, 'main'), which breaks the code.

Deparsing as bless({}, 'main') would still leave broken code such as

  use constant OBJ => bless({});
  $a = OBJ;
  print $a == OBJ;

-zefram

@p5pRT
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p5pRT commented Jul 2, 2017

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

@p5pRT
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p5pRT commented Jul 2, 2017

From @demerphq

On 2 July 2017 at 12​:14, Zefram <zefram@​fysh.org> wrote​:

l.mai@​web.de wrote​:

OBJ is deparsed as {} instead of bless({}, 'main'), which breaks the code.

Deparsing as bless({}, 'main') would still leave broken code such as

    use constant OBJ => bless\(\{\}\);
    $a = OBJ;
    print $a == OBJ;

Shouldn't it deparse it as OBJ? In a perfect world...

Yves

--
perl -Mre=debug -e "/just|another|perl|hacker/"

@p5pRT
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p5pRT commented Jul 2, 2017

From @cpansprout

On Sun, 02 Jul 2017 03​:22​:40 -0700, demerphq wrote​:

On 2 July 2017 at 12​:14, Zefram <zefram@​fysh.org> wrote​:

l.mai@​web.de wrote​:

OBJ is deparsed as {} instead of bless({}, 'main'), which breaks the code.

Deparsing as bless({}, 'main') would still leave broken code such as

    use constant OBJ => bless\(\{\}\);
    $a = OBJ;
    print $a == OBJ;

Shouldn't it deparse it as OBJ? In a perfect world...

Yes, and that feature made deparse unworkably slow for many practical uses, so it got reverted before 5.10 or 5.12, whichever it was.

--

Father Chrysostomos

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