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Report information
Id: 77496
Status: resolved
Priority: 0/
Queue: perl5

Owner: Nobody
Requestors: sprout <sprout [at] cpan.org>
Cc:
AdminCc:

Operating System: darwin
PatchStatus: (no value)
Severity: low
Type:
Perl Version: 5.13.4
Fixed In: (no value)



Subject: tied gets scalars and globs confused
Date: Sun, 29 Aug 2010 13:38:11 -0700
To: perlbug [...] perl.org
From: Father Chrysostomos <sprout [...] cpan.org>
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(I must be tired today. This is the second bug report I’ve muddled up. I sent it first without the perlbug output. It disappeared, but—who knows?—it may pop up again someday.) In trying to write a test for an assignment bug, I came across this anomaly with tied(): sub TIESCALAR {bless[]} sub FETCH { 1 } sub STORE{} tie $rin, ""; $rin = *rin; print qw[good bad][!tied $rin]; tied returns undef, so this prints ‘bad’. tied checks first to see whether its argument is a glob. If it is, it returns undef if the IO slot is empty. So the the tiedness, according to tied(), varies depending on what the last value happened to be that was returned or assigned. --- Flags: category=core severity=low --- Site configuration information for perl 5.13.4: Configured by sprout at Fri Aug 20 23:24:53 PDT 2010. Summary of my perl5 (revision 5 version 13 subversion 4 patch v5.13.4-16-g16c9153) configuration: Snapshot of: 9b47cddefd9b4a322e6382c8979ceeb2c3ac25c9 Platform: osname=darwin, osvers=10.4.0, archname=darwin-2level uname='darwin pint.local 10.4.0 darwin kernel version 10.4.0: fri apr 23 18:28:53 pdt 2010; root:xnu-1504.7.4~1release_i386 i386 ' config_args='-de -Dusedevel' hint=recommended, useposix=true, d_sigaction=define useithreads=undef, usemultiplicity=undef useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef use64bitint=undef, use64bitall=undef, uselongdouble=undef usemymalloc=n, bincompat5005=undef Compiler: cc='cc', ccflags ='-fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include', optimize='-O3', cppflags='-no-cpp-precomp -fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include' ccversion='', gccversion='4.2.1 (Apple Inc. build 5664)', gccosandvers='' intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234 d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16 ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8 alignbytes=8, prototype=define Linker and Libraries: ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -fstack-protector -L/usr/local/lib' libpth=/usr/local/lib /usr/lib libs=-ldbm -ldl -lm -lutil -lc perllibs=-ldl -lm -lutil -lc libc=/usr/lib/libc.dylib, so=dylib, useshrplib=false, libperl=libperl.a gnulibc_version='' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' ' cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector' Locally applied patches: --- @INC for perl 5.13.4: /usr/local/lib/perl5/site_perl/5.13.4/darwin-2level /usr/local/lib/perl5/site_perl/5.13.4 /usr/local/lib/perl5/5.13.4/darwin-2level /usr/local/lib/perl5/5.13.4 /usr/local/lib/perl5/site_perl . --- Environment for perl 5.13.4: DYLD_LIBRARY_PATH (unset) HOME=/Users/sprout LANG=en_US.UTF-8 LANGUAGE (unset) LD_LIBRARY_PATH (unset) LOGDIR (unset) PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/local/bin PERL_BADLANG (unset) SHELL=/bin/bash
Subject: [PATCH] Re: [perl #77496] tied gets scalars and globs confused
Date: Sun, 29 Aug 2010 13:43:02 -0700
To: perlbug-followup [...] perl.org
From: Father Chrysostomos <sprout [...] cpan.org>
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On Aug 29, 2010, at 1:38 PM, Father Chrysostomos wrote:

Show quoted text
In trying to write a test for an assignment bug, I came across this anomaly with tied():

sub TIESCALAR {bless[]}
sub FETCH { 1 }
sub STORE{}
tie $rin, "";
$rin = *rin;
print qw[good bad][!tied $rin];

tied returns undef, so this prints ‘bad’. tied checks first to see whether its argument is a glob. If it is, it returns undef if the IO slot is empty.

So the the tiedness, according to tied(), varies depending on what the last value happened to be that was returned or assigned.

There should be a patch attached hereto. I put the explanation of OPf_SPECIAL above OP_HELEM to avoid a conflict with the patch for bug #20444.

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On Sun Aug 29 13:43:32 2010, sprout wrote: Show quoted text
> > On Aug 29, 2010, at 1:38 PM, Father Chrysostomos wrote: >
> > In trying to write a test for an assignment bug, I came across this
> anomaly with tied():
> > > > sub TIESCALAR {bless[]} > > sub FETCH { 1 } > > sub STORE{} > > tie $rin, ""; > > $rin = *rin; > > print qw[good bad][!tied $rin]; > > > > tied returns undef, so this prints ‘bad’. tied checks first to see
> whether its argument is a glob. If it is, it returns undef if the IO > slot is empty.
> > > > So the the tiedness, according to tied(), varies depending on what
> the last value happened to be that was returned or assigned. > > There should be a patch attached hereto.
I have applied a simplified version as 8752206. (2acc3314 allows pp_tied to check just the FAKE flag on a glob, to determine whether it should be considered one.)
I’ve re-opened this, since the fix was reverted for 5.14. See #79528.
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On Wed Apr 20 14:32:56 2011, sprout wrote: Show quoted text
> I’ve re-opened this, since the fix was reverted for 5.14. See #79528.
And now I’m closing it, as the revert was reverted as 4be76e1f2b.


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