From rmiller@rmiller1.idx.com

The following two-line file illustrates the problem​:

  my @​res = ("A\n");
  print @​res;

Running this with "perl -w" or "perl -w -d" produces the expected output
(a line containing the single letter 'A'). But in the perl debugger,
the command
  x @​res
given after the first line executes, but before the second start,
erroneously reports
  empty array

Site configuration information for perl 5.00503:

Configured by root at Mon Aug 30 23:08:56 EDT 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=linux, osvers=2.2.5-22smp, archname=i386-linux
    uname='linux porky.devel.redhat.com 2.2.5-22smp #1 smp wed jun 2 09:11:51 edt 1999 i686 unknown '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  Compiler:
    cc='cc', optimize='-O2', gccversion=egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
    cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    stdchar='char', d_stdstdio=undef, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    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 -ldl -lm -lc -lposix -lcrypt
    libc=, 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'

Locally applied patches:
    


@INC for perl 5.00503:
    /usr/local/bin/perl
    /home/rmiller/rel/pmake
    /usr/lib/perl5/5.00503/i386-linux
    /usr/lib/perl5/5.00503
    /usr/lib/perl5/site_perl/5.005/i386-linux
    /usr/lib/perl5/site_perl/5.005
    .


Environment for perl 5.00503:
    HOME=/home/rmiller
    LANG=en_US
    LANGUAGE (unset)
    LC_ALL=en_US
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/home/rmiller/bin:.
    PERL5LIB=/usr/local/bin/perl:/home/rmiller/rel/pmake
    PERL_BADLANG (unset)
    SHELL=/bin/bash

From [Unknown Contact. See original ticket]

Rich Miller writes​:

my @​res = \("A\\n"\);
print @​res;

Running this with "perl -w" or "perl -w -d" produces the expected output
(a line containing the single letter 'A'). But in the perl debugger,
the command
x @​res
given after the first line executes, but before the second start,
erroneously reports
empty array

More datapoints​:

  DB<1> print @​res

  DB<2> eval 'print @​res'
A

Something fishy... eval '...' does not see it, but eval q(eval '...') can
see it...

Ilya

From @tamias

On Thu, Jan 27, 2000 at 06​:31​:01PM -0500, Ilya Zakharevich wrote​:

Rich Miller writes​:

my @​res = \("A\\n"\);
print @​res;

Running this with "perl -w" or "perl -w -d" produces the expected output
(a line containing the single letter 'A'). But in the perl debugger,
the command
x @​res
given after the first line executes, but before the second start,
erroneously reports
empty array

More datapoints​:

DB<1> print @​res

DB<2> eval 'print @​res'
A

Something fishy... eval '...' does not see it, but eval q(eval '...') can
see it...

This is probably the problem​:

[...]/lib/perl5/5.00503> grep \@​res perl5db.pl
  my @​res;
  @​res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive
  debug
  dumpit($OUT, \@​res);
  @​res;

Ronald

From [Unknown Contact. See original ticket]

On Thu, Jan 27, 2000 at 06​:37​:49PM -0500, Ronald J Kimball wrote​:

DB<1> print @​res

DB<2> eval 'print @​res'
A

Something fishy... eval '...' does not see it, but eval q(eval '...') can
see it...

This is probably the problem​:

[...]/lib/perl5/5.00503> grep \@​res perl5db.pl
my @​res;
@​res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive
debug
dumpit($OUT, \@​res);
@​res;

Thanks!!! I was going to go mad...

--- ./lib/perl5db.pl~	Tue Nov 30 22:47:10 1999
+++ ./lib/perl5db.pl	Thu Jan 27 18:55:55 2000
@@ -1254,11 +1254,11 @@ sub save {
 # The following takes its argument via $evalarg to preserve current @_
 
 sub eval {
-    my @res;
+    local @res;			# 'my' would make it visible from user code
     {
-	my $otrace = $trace;
-	my $osingle = $single;
-	my $od = $^D;
+	local $otrace = $trace;
+	local $osingle = $single;
+	local $od = $^D;
 	@res = eval "$usercontext $evalarg;\n"; # '\n' for nice recursive debug
 	$trace = $otrace;
 	$single = $osingle;

Enjoy,
Ilya