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Empty slice arg with ($;$) prototype #7422

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p5pRT opened this issue Jul 13, 2004 · 5 comments
Closed

Empty slice arg with ($;$) prototype #7422

p5pRT opened this issue Jul 13, 2004 · 5 comments
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distro-Linux type-core

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@p5pRT
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p5pRT commented Jul 13, 2004

Migrated from rt.perl.org#30688 (status was 'resolved')

Searchable as RT30688$
@p5pRT
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p5pRT commented Jul 13, 2004

From mike@mikero.com

Created by mike@mikero.com

# Passing @​array[()] as the second arg to a ($;$) prototyped sub
# actually passes the first arg twice! This is different behavior
# from passing () or (list,of,things)[()] as the second arg. It's
# also the same for hash slices

sub foo($;$) { print map("<$_>", @​_), $/; }
my @​a;
my @​b = (1,2,3);
my %h;

foo 1, 2; # <1><2>
foo 1; # <1>

foo {}, {}; # <HASH(0x814cbb8)><HASH(0x814cd44)>
foo {}; # <HASH(0x814cbb8)>

foo {}, @​a; # <HASH(0x814cbb8)><0>
foo {}, (); # <HASH(0x814cbb8)><>

foo {}, @​a[0..$#a]; # <HASH(0x814cbb8)><HASH(0x814cbb8)>
foo {}, @​a[()]; # <HASH(0x814cbb8)><HASH(0x814cbb8)>
  # these two cases pass the same argument twice!

foo {}, (1,2,3)[()]; # <HASH(0x814cbb8)><>
foo {}, @​b[()]; # <HASH(0x814cbb8)><HASH(0x814cbb8)>
  # array doesn't have to be empty
 
foo {}, @​h[()]; # <HASH(0x814cbb8)><HASH(0x814cbb8)>
  # hash slices too

__END__

Perl Info 

Flags:
    category=core
    severity=low

Site configuration information for perl v5.8.4:

Configured by Debian Project at Wed May 12 00:32:16 EST 2004.

Summary of my perl5 (revision 5 version 8 subversion 4) configuration:
  Platform:
    osname=linux, osvers=2.4.26-ti1211, archname=i386-linux-thread-multi
    uname='linux kosh 2.4.26-ti1211 #1 sat apr 24 14:46:58 est 2004 i686
    gnulinux '
    config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN
    -Dcccdlflags=-fPIC -Darchname=i386-linux -Dprefix=/usr
    -Dprivlib=/usr/share/perl/5.8 -Darchlib=/usr/lib/perl/5.8
    -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5
    -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local
    -Dsitelib=/usr/local/share/perl/5.8.4
    -Dsitearch=/usr/local/lib/perl/5.8.4 -Dman1dir=/usr/share/man/man1
    -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1
    -Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl
    -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Uusesfio -Uusenm
    -Duseshrplib -Dlibperl=libperl.so.5.8.4 -Dd_dosuid -des'
    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='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS
    -DDEBIAN -fno-strict-aliasing -I/usr/local/include
    -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN
    -fno-strict-aliasing -I/usr/local/include'
    ccversion='', gccversion='3.3.3 (Debian 20040429)', 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='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
    perllibs=-ldl -lm -lpthread -lc -lcrypt
    libc=/lib/libc-2.3.2.so, so=so, useshrplib=true,
    libperl=libperl.so.5.8.4
    gnulibc_version='2.3.2'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    


@INC for perl v5.8.4:
    /etc/perl
    /usr/local/lib/perl/5.8.4
    /usr/local/share/perl/5.8.4
    /usr/lib/perl5
    /usr/share/perl5
    /usr/lib/perl/5.8
    /usr/share/perl/5.8
    /usr/local/lib/site_perl
    /usr/local/lib/perl/5.8.3
    /usr/local/share/perl/5.8.3
    /usr/local/lib/perl/5.8.2
    /usr/local/share/perl/5.8.2
    /usr/local/lib/perl/5.8.1
    /usr/local/share/perl/5.8.1
    /usr/local/lib/perl/5.8.0
    /usr/local/share/perl/5.8.0
    .


Environment for perl v5.8.4:
    HOME=/home/mjr
    LANG=C
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games
    PERL5_CPANPLUS_CONFIG=/home/mjr/.cpanplus/config
    PERL_BADLANG (unset)
    SHELL=/bin/bash

@p5pRT
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p5pRT commented Jul 20, 2004

From rick@bort.ca

On Tue, Jul 13, 2004 at 04​:59​:31AM -0000, Mike Rosulek wrote​:

sub foo($;$) { print map("<$_>", @​_), $/; }
...
foo {}, @​a[()]; # <HASH(0x814cbb8)><HASH(0x814cbb8)>
# these two cases pass the same argument twice!

Messed up stack pointer for empty slices in scalar context.

--
Rick Delaney
rick@​bort.ca

Inline Patch 
--- perl-current/pp.c	Wed Jul 14 12:00:46 2004
+++ perl-dev/pp.c	Tue Jul 20 15:33:45 2004
@@ -3749,7 +3749,7 @@
     }
     if (GIMME != G_ARRAY) {
 	MARK = ORIGMARK;
-	*++MARK = *SP;
+	*++MARK = SP > ORIGMARK ? *SP : &PL_sv_undef;
 	SP = MARK;
     }
     RETURN;
@@ -3949,7 +3949,7 @@
     }
     if (GIMME != G_ARRAY) {
 	MARK = ORIGMARK;
-	*++MARK = *SP;
+	*++MARK = SP > ORIGMARK ? *SP : &PL_sv_undef;
 	SP = MARK;
     }
     RETURN;
--- perl-current/t/op/list.t	Mon Jul 31 22:32:13 2000
+++ perl-dev/t/op/list.t	Tue Jul 20 15:09:13 2004
@@ -1,6 +1,6 @@
 #!./perl
 
-print "1..28\n";
+print "1..30\n";
 
 @foo = (1, 2, 3, 4);
 if ($foo[0] == 1 && $foo[3] == 4) {print "ok 1\n";} else {print "not ok 1\n";}
@@ -86,4 +86,13 @@
     my @c = (0, undef, undef, 3)[1, 2];
     print "not " unless @b == @c and @c == 2;
     print "ok 28\n";
+
+    @b = (29, scalar @c[()]);
+    print "not " if join(':',@b) ne '29:';
+    print "ok 29\n";
+
+    my %h = (a => 1);
+    @b = (30, scalar @h{()});
+    print "not " if join(':',@b) ne '30:';
+    print "ok 30\n";
 }

@p5pRT
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p5pRT commented Jul 20, 2004

The RT System itself - Status changed from 'new' to 'open'

@p5pRT
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p5pRT commented Jul 21, 2004

From @rgs

Rick Delaney wrote​:

On Tue, Jul 13, 2004 at 04​:59​:31AM -0000, Mike Rosulek wrote​:

sub foo($;$) { print map("<$_>", @​_), $/; }
...
foo {}, @​a[()]; # <HASH(0x814cbb8)><HASH(0x814cbb8)>
# these two cases pass the same argument twice!

Messed up stack pointer for empty slices in scalar context.

Thanks, applied to blead as change #23145.

--- perl-current/pp.c Wed Jul 14 12​:00​:46 2004
+++ perl-dev/pp.c Tue Jul 20 15​:33​:45 2004

@p5pRT p5pRT closed this as completed Jul 22, 2004
@p5pRT
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p5pRT commented Jul 22, 2004

@rspier - Status changed from 'open' to 'resolved'

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