[perl #38034] A combination eval, DESTROY method and $@ - dangerous - bug

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# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/rt3/Ticket/Display.html?id=38034 >


This is a bug report for perl from root@localhost.localdomain,
generated with the help of perlbug 1.34 running under perl v5.8.0.


-----------------------------------------------------------------
[Please enter your report here]


Brief:
If an some object is created in eval block under my operator and this object has a DESTROY method (for example, disconnect database method) then any threw exceptions in eval block are wiped and lost. I think that this is incorrect behaviour of perl. The perl should keep $@ if in eval there is some DESTROY methods...

To see example below

// Perlover (perlover@perlover.com)
Example:

eval

{
 my $alex = Alex->new();
 $alex->alex();
};

my $error = $@;

print "error = $error\n";


{
 package Alex;

 sub new
{
 return bless {}, shift;
}

 sub DESTROY
 {
  $@ = undef;
 }

sub alex
{
 die "Vasya cool";
}
}

[Please do not change anything below this line]
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---
Flags:
    category=core
    severity=medium
---
This perlbug was built using Perl v5.8.0 in the Red Hat build system.
It is being executed now by Perl v5.8.0 - Sat Dec 11 01:51:59 GMT 2004.

Site configuration information for perl v5.8.0:

Configured by root at Sat Dec 11 01:51:59 GMT 2004.

Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.4.21-20.0.1.el, archname=i386-linux-thread-multi
    uname='linux centos-build 2.4.21-20.0.1.el #1 fri dec 3 02:17:26 gmt 2004 i686 athlon i386 gnulinux '
    config_args='-des -Doptimize=-O2 -g -pipe -march=i386 -mcpu=i686 -Dmyhostname=localhost -Dperladmin=root@localhost -Dcc=gcc -Dcf_by=Red Hat, Inc. -Dinstallprefix=/usr -Dprefix=/usr -Darchname=i386-linux -Dvendorprefix=/usr -Dsiteprefix=/usr -Dotherlibdirs=/usr/lib/perl5/5.8.0 -Duseshrplib -Dusethreads -Duseithreads -Duselargefiles -Dd_dosuid -Dd_semctl_semun -Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=3pm -Duseperlio -Dinstallusrbinperl -Ubincompat5005 -Uversiononly -Dpager=/usr/bin/less -isr'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define use5005threads=undef useithreads=define usemultiplicity=define
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBUGGING -fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm',
    optimize='-O2 -g -pipe -march=i386 -mcpu=i686',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBUGGING -fno-strict-aliasing -I/usr/local/include -I/usr/include/gdbm'
    ccversion='', gccversion='3.2.3 20030502 (Red Hat Linux 3.2.3-42)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='gcc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lgdbm -ldb -ldl -lm -lpthread -lc -lcrypt -lutil
    perllibs=-lnsl -ldl -lm -lpthread -lc -lcrypt -lutil
    libc=/lib/libc-2.3.2.so, so=so, useshrplib=true, libperl=libperl.so
    gnulibc_version='2.3.2'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic -Wl,-rpath,/usr/lib/perl5/5.8.0/i386-linux-thread-multi/CORE'
    cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    MAINT18379

---
@INC for perl v5.8.0:
    /usr/lib/perl5/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/5.8.0
    /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.0
    /usr/lib/perl5/site_perl
    /usr/lib/perl5/vendor_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.0
    /usr/lib/perl5/vendor_perl
    /usr/lib/perl5/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/5.8.0
    .

---
Environment for perl v5.8.0:
    HOME=/root
    LANG=en_US.iso885915
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/X11R6/bin:/root/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash

• [perl #38034] A combination eval, DESTROY method and $@ - dangerous - bug by root @ localhost . localdomain