[ID 20000405.013] Bug in Carp::Heavy?

=== forwarded message ===

I'm not sure if this is a bug or what.

BTW, I tried sending a bug report twice and it didn't go through so
instead I'll send a patch.

Anyway, under 5.6.0 it seems that the results of caller have changed ever
so slightly.  Previously, when eval'ing a block {} (caller(0))[6]
(evaltext) was not returned at all (it returned a 5 elements list).  Under
perl5.6.0 it now returns 0.  This caused a problem in
Carp::Heavy::longmess which made it print stuff like a require had
happened.

Here's a quick test script that illustrates the issue (compare under
5.00503 to 5.6.0):

use Carp;

eval {
    print join ' ', map {defined $_ ? $_ : 'undef'} caller(0);
    print "\n";
    confess 'foo';
};
print $@;


Here's a patch:

--- /usr/local/lib/perl5/5.6.0/Carp/H   Tue Apr  4 23:10:47 2000
+++ /usr/local/lib/perl5/5.6.0/Carp/Heavy.pm    Tue Apr  4 23:17:56 2000
@@ -58,7 +58,7 @@
        } else {
            # Build a string, $sub, which names the sub-routine called.
            # This may also be "require ...", "eval '...' or "eval {...}"
-           if (defined $eval) {
+           if ($eval) {
                if ($require) {
                    $sub = "require $eval";
                } else {

The only problem (and it's not much of one) is that if you were to do:

$SIG{__DIE__} = sub { confess(@_) };

and then do:

eval '0';

and that eval caused a fatal error (dunno how though) it might cause Carp
to report incorrectly.  OTOH, I think that's a heck of a rare special
case.  OTOH (yes, I have 3) maybe the Perl core needs to be changed to
revert to the previous behavior of returning a 5 element list.


and here's my perl -V:

Summary of my perl5 (revision 5.0 version 6 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.2.5-15, archname=i586-linux
    uname='linux urth.org 2.2.5-15 #15 mon jul 5 01:48:48 cdt 1999 i586
unknown '
    config_args=''
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef
usemultiplicity=undef
    useperlio=undef d_sfio=undef uselargefiles=define 
    use64bitint=undef use64bitall=undef uselongdouble=undef usesocks=undef
  Compiler:
    cc='cc', optimize='-O2', gccversion=2.95.1 19990816 (release)
    cppflags='-fno-strict-aliasing -I/usr/local/include'
    ccflags ='-fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    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, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lndbm -lgdbm -ldb -ldl -lm -lc -lposix -lcrypt
    libc=/lib/libc-2.1.1.so, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl): 
  Compile-time options: USE_LARGE_FILES
  Built under linux
  Compiled at Mar 23 2000 12:04:27
  @INC:
    /usr/local/lib/perl5/5.6.0/i586-linux
    /usr/local/lib/perl5/5.6.0
    /usr/local/lib/perl5/site_perl/5.6.0/i586-linux
    /usr/local/lib/perl5/site_perl/5.6.0
    /usr/local/lib/perl5/site_perl
    .

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• [ID 20000405.013] Bug in Carp::Heavy? by Richard Foley