inconsistency between PerlIO::get_layers and open/binmode

[p5pRT]

Migrated from rt.perl.org#35180 (status was 'open')

Searchable as RT35180$

[p5pRT]

From laurent.dami@justice.ge.ch

use PerlIO;

open F, "foo.pl";


# now try to open a temp file with same layers as F
my $tmp = undef;
my $F_layers = join "", map {":$_"} PerlIO::get_layers(F);
open $tmp, "+>$F_layers", undef;

my $tmp_layers = join "", map {":$_"} PerlIO::get_layers($tmp);

print "MISMATCH !! $F_layers / $tmp_layers\n" unless $F_layers eq
$tmp_layers;

# on Win32 : MISMATCH !! :unix:crlf / :unix:crlf:unix

__END__

Perl Info

Site configuration information for perl v5.8.6:

Configured by damil at Wed Dec 22 15:20:14 2004.

Summary of my perl5 (revision 5 version 8 subversion 6) configuration:
Platform:
osname=MSWin32, osvers=4.0, archname=MSWin32-x86-multi-thread
uname=''
config_args='undef'
hint=recommended, useposix=true, d_sigaction=undef
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='cl', ccflags ='-nologo -Gf -W3 -MD -DNDEBUG -O1 -DWIN32 -D_CONSOLE
-DNO_STRICT -DHAVE_DES_FCRYPT -DNO_HASH_SEED -DPERL_IMPLICIT_CONTEXT
-DPERL_IMPLICIT_SYS -DUSE_PERLIO -DPERL_MSVCRT_READFIX',
optimize='-MD -DNDEBUG -O1',
cppflags='-DWIN32'
ccversion='', gccversion='', gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=10
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='__int64',
lseeksize=8
alignbytes=8, prototype=define
Linker and Libraries:
ld='link', ldflags ='-nologo -nodefaultlib -release
-libpath:"c:\Perl\lib\CORE" -machine:x86'
libpth=\lib
libs= oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib netapi32.lib
uuid.lib ws2_32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib
msvcrt.lib
perllibs= oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib netapi32.lib
uuid.lib ws2_32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib
msvcrt.lib
libc=msvcrt.lib, so=dll, useshrplib=yes, libperl=perl58.lib
gnulibc_version='undef'
Dynamic Linking:
dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib -release
-libpath:"c:\Perl\lib\CORE" -machine:x86'

Locally applied patches:
ACTIVEPERL_LOCAL_PATCHES_ENTRY
21540 Fix backward-compatibility issues in if.pm
23565 Wrong MANIFEST.SKIP

---
@INC for perl v5.8.6:
C:/Perl/lib
C:/Perl/site/lib
.

---
Environment for perl v5.8.6:
HOME=c:/dami
LANG (unset)
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=C:\Program Files\XEmacs\XEmacs-21.4.13\i586-pc-win32;c:\program
files\imagemagick-5.4.9-q16;C:\Perl\bin\;C:\orant\bin;C:\Program
Files\Microsoft.NET\FrameworkSDK\Bin\;C:\Program Files\Microsoft Visual
Studio
.NET\Common7\IDE\;C:\WINDOWS\Microsoft.NET\Framework\v1.0.3705\;C:\Program
Files\Microsoft Visual Studio
.NET\Vc7\bin\;C:\texmf\miktex\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\
System32\Wbem;C:\Program Files\Fichiers communs\Adaptec
Shared\System;C:\BASISclient\cs\bin;C:\BASISclient\www\bin;c:\Unix;c:\progra
m files\minGW\bin;C:\Program Files\j2sdk1.4.1_01\bin;C:\Program
Files\Support Tools\
PERL_BADLANG (unset)
SHELL (unset)




Laurent Dami
Conseiller en syst�mes d'information
Palais de Justice - Etat de Gen�ve
Case postale 3966
Place du Bourg-de-Four 3, 1211 Gen�ve 3
+41 (22) 327 20 64 (direct), +41 (22) 327 20 37 (service)
http://cui.unige.ch/~dami

[p5pRT]

From @rgs

I'm not sure that's really a bug, since open pushes some layers by
defaults depending on the platform. That's more a minor annoyance.

[p5pRT]

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

[p5pRT]

From Peter.Dintelmann@dresdner-bank.com

":unix:crlf" seem to be the default layers on this platform. When $tmp is opened

open $tmp, "+>$F_layers", undef;

":unix:crlf" ($F_layers) are pushed on top of the default layers resulting in ":unix:crlf:unix:crlf" for $tmp. However ":crlf" is documented to be pushed only once

:crlf
A layer that implements DOS/Windows like CRLF line endings.
... ...
Note that this layer likes to be one of its kind: it silently
ignores attempts to be pushed into the layer stack more than once.
... ...

and the result is ":unix:crlf:unix" (the rightmost ":crlf" is silently ignored).

IMHO your code behaves exactly as documented.

[p5pRT]

From nick@ing-simmons.net

But the odd thing is if undef is replaced by a file name it works
as original poster expected.
So it seems the magic undef for temp file code is getting extra
set of layers.

[toddr]

On UNIX my output is currently this on 5.30

MISMATCH !!  / :unix:perlio

@Leont can you comment on this?

[Leont]

This is a known issue, though I'm not sure if it has a ticket.

Our tempfile implementation is buggy with regards to layers, it applies them twice.