[perl #121048] illegal sub declaration crashes

[Zefram (via RT)]

# New Ticket Created by Zefram
# Please include the string: [perl #121048]
# in the subject line of all future correspondence about this issue.
# <URL: https://rt.perl.org/Ticket/Display.html?id=121048 >



This is a bug report for perl from ***@fysh.org,
generated with the help of perlbug 1.39 running under perl 5.19.7.


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

$ perl -lwe 'BEGIN <> { }'
Use of uninitialized value at -e line 1.
zsh: segmentation fault perl -lwe 'BEGIN <> { }'

This takes a funny path through the tokeniser. "BEGIN" and a few other
keywords get treated as if "sub" had been said first. The "sub" handler
has an explicit check for unexpected stuff preceding the body:

$ perl -lwe 'sub BEGIN <> { }'
Illegal declaration of subroutine main::BEGIN at -e line 1.

But the "sub" handler doesn't apply this check if the "sub" keyword
wasn't really there.

I haven't looked into what actually makes this crash. In theory the
check should be entirely redundant: if the next token isn't one of the
permitted ones then a simple syntax error should result.

[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
category=core
severity=low
---
Site configuration information for perl 5.19.7:

Configured by zefram at Mon Dec 23 19:18:49 GMT 2013.

Summary of my perl5 (revision 5 version 19 subversion 7) configuration:

Platform:
osname=linux, osvers=3.2.0-4-amd64, archname=x86_64-linux-thread-multi
uname='linux barba.rous.org 3.2.0-4-amd64 #1 smp debian 3.2.46-1 x86_64 gnulinux '
config_args='-des -Dprefix=/home/zefram/usr/perl/perl_install/perl-5.19.7-i64-f52 -Duselargefiles -Dusethreads -Uafs -Ud_csh -Uusesfio -Uusenm -Duseshrplib -Dusedevel -Uversiononly -Ui_db'
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 -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
optimize='-O2',
cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
ccversion='', gccversion='4.7.2', 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 =' -fstack-protector -L/usr/local/lib'
libpth=/usr/local/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /usr/lib
libs=-lnsl -ldb -ldl -lm -lcrypt -lutil -lpthread -lc
perllibs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
libc=, so=so, useshrplib=true, libperl=libperl.so
gnulibc_version='2.15'
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E -Wl,-rpath,/home/zefram/usr/perl/perl_install/perl-5.19.7-i64-f52/lib/5.19.7/x86_64-linux-thread-multi/CORE'
cccdlflags='-fPIC', lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector'


---
@INC for perl 5.19.7:
/home/zefram/usr/perl/perl_install/perl-5.19.7-i64-f52/lib/site_perl/5.19.7/x86_64-linux-thread-multi
/home/zefram/usr/perl/perl_install/perl-5.19.7-i64-f52/lib/site_perl/5.19.7
/home/zefram/usr/perl/perl_install/perl-5.19.7-i64-f52/lib/5.19.7/x86_64-linux-thread-multi
/home/zefram/usr/perl/perl_install/perl-5.19.7-i64-f52/lib/5.19.7
.

---
Environment for perl 5.19.7:
HOME=/home/zefram
LANG (unset)
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/home/zefram/usr/perl/perl_install/perl-5.19.7-i64-f52/bin:/home/zefram/usr/perl/util:/home/zefram/pub/x86_64-unknown-linux-gnu/bin:/home/zefram/pub/common/bin:/usr/bin:/bin:/usr/local/bin:/usr/games
PERL_BADLANG (unset)
SHELL=/usr/bin/zsh

[Reini Urban via RT]

Please see my patch at RT #125341