[perl #119949] local *_; goto ⊂ segfaults on 5.18

# New Ticket Created by  Brian Fraser 
# Please include the string:  [perl #119949]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=119949 >


This is a bug report for perl from fraserb@gmail.com,
generated with the help of perlbug 1.39 running under perl 5.18.1.


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

sub foo { say "in foo: <@_>" }
sub bar { local *_ = "hello foo"; goto &foo }
bar("hello bar")

This incorrectly prints "in foo: <hello bar>" in 5.16, and segfaults in
5.18 and 5.19.4. It should probably just give an uninit warning and print
"in foo: <>".
This is likely a leftover from making 'local @_ = ...; goto &sub;' work.
Something in pp_leavesub is likely making unwarranted assumptions about
GvAV(PL_defav) or cx->blk_sub.argarray.

[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
    category=core
    severity=medium
---
Site configuration information for perl 5.18.1:

Configured by hugmeir at Thu Sep 12 14:58:14 ART 2013.

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

  Platform:
    osname=darwin, osvers=12.4.0, archname=darwin-thread-multi-2level
    uname='darwin airtiger 12.4.0 darwin kernel version 12.4.0: wed may 1
17:57:12 pdt 2013; root:xnu-2050.24.15~1release_x86_64 x86_64 '
    config_args='-de
-Dprefix=/Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1 -Dusethreads
-DDEBUGGING
-Aeval:scriptdir=/Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1/bin'
    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 ='-fno-common -DPERL_DARWIN -DDEBUGGING
-fno-strict-aliasing -pipe -fstack-protector',
    optimize='-O3 -g',
    cppflags='-fno-common -DPERL_DARWIN -DDEBUGGING -fno-strict-aliasing
-pipe -fstack-protector'
    ccversion='', gccversion='4.2.1 Compatible Apple LLVM 4.2
(clang-425.0.28)', 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='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -fstack-protector'
    libpth=/usr/lib
    libs=-ldbm -ldl -lm -lutil -lc
    perllibs=-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=' -bundle -undefined dynamic_lookup
-fstack-protector'

Locally applied patches:


---
@INC for perl 5.18.1:
    /Users/hugmeir/.perlbrew/libs/perl-5.16.2@all
/lib/perl5/darwin-thread-multi-2level
    /Users/hugmeir/.perlbrew/libs/perl-5.16.2@all/lib/perl5

/Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1/lib/site_perl/5.18.1/darwin-thread-multi-2level
    /Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1/lib/site_perl/5.18.1

/Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1/lib/5.18.1/darwin-thread-multi-2level
    /Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1/lib/5.18.1
    .

---
Environment for perl 5.18.1:
    DYLD_LIBRARY_PATH=/usr/local/mysql/lib:
    HOME=/Users/hugmeir
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)

PATH=/Users/hugmeir/perl5/perlbrew/bin:/Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin:/usr/local/mysql/bin
    PERL5LIB=/Users/hugmeir/.perlbrew/libs/perl-5.16.2@all/lib/perl5
    PERLBREW_BASHRC_VERSION=0.58
    PERLBREW_HOME=/Users/hugmeir/.perlbrew
    PERLBREW_LIB=all
    PERLBREW_MANPATH=/Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1/man

PERLBREW_PATH=/Users/hugmeir/perl5/perlbrew/bin:/Users/hugmeir/perl5/perlbrew/perls/perl-5.18.1/bin
    PERLBREW_PERL=perl-5.18.1
    PERLBREW_ROOT=/Users/hugmeir/perl5/perlbrew
    PERLBREW_VERSION=0.58
    PERL_BADLANG (unset)
    PERL_LOCAL_LIB_ROOT=/Users/hugmeir/.perlbrew/libs/perl-5.16.2@all
    PERL_MB_OPT=--install_base /Users/hugmeir/.perlbrew/libs/perl-5.16.2@all
    PERL_MM_OPT=INSTALL_BASE=/Users/hugmeir/.perlbrew/libs/perl-5.16.2@all
    SHELL=/bin/bash

• [perl #119949] local *_; goto ⊂ segfaults on 5.18 by Brian Fraser
• Re: [perl #119949] local *_; goto ⊂ segfaults on 5.18 by Nicholas Clark