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[perl #120388] File::Find::fullname sometimes undef for plain files

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From:
Jim Avera
Date:
October 27, 2013 23:21
Subject:
[perl #120388] File::Find::fullname sometimes undef for plain files
Message ID:
rt-4.0.18-15399-1382916081-868.120388-75-0@perl.org
# New Ticket Created by  Jim Avera 
# Please include the string:  [perl #120388]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=120388 >



This is a bug report for perl from james_avera@yahoo.com,
generated with the help of perlbug 1.39 running under perl 5.14.2.

-----------------------------------------------------------------
File::Find with follow=>1 sometimes sets File::Find::fullname to
undef when calling wanted() for a plain file not involving symlinks.

This occurs if a symlink elsewhere in the tree refers to the plain
file being processed by wanted().  See demo script below.

If bug will not be fixed, or if it is not really a bug, then it would
be helpful if the pod for File::Find documented all the conditions
under which File::Find::fullname could be undef.


#!/usr/bin/perl
use strict; use warnings;
use File::Find qw(find);
sub u($) { defined $_[0] ? "'$_[0]'" : "undef" }

my $d = "/tmp/testdir";
system "rm", "-rf", $d;
die unless mkdir $d;
die unless mkdir "$d/subdir";
die unless mkdir "$d/subdir/subsubdir";
die unless 0==system "touch", "$d/file1";
die unless 0==system "touch", "$d/subdir/file";
die unless symlink "/etc/passwd",   "$d/subdir/symlink_to_exterior";
die unless symlink "/no such file", "$d/dangling";

# this one triggers the bug
die unless symlink "$d/subdir/file", "$d/subdir/symlink_to_interior";

find({ #dangling_symlinks => 1,
       #follow_skip => 2,  #ignore duplicates but proceed normally otherwise
       follow => 1, 
       wanted=>sub {
         lstat $_;
         my $type = (-f _ ? "  file " : -d _ ? "   dir " : -l _ ? "symlink" : "other");
         if (defined($File::Find::fullname) 
               && $File::Find::fullname eq $File::Find::name) {
           warn "$type : $File::Find::name\n";
         } else {
           warn "$type : name=",u($File::Find::name), 
                " fullname=",u($File::Find::fullname),"\n";
         }
         if (-f $File::Find::name && ! defined $File::Find::fullname) {
           system "set -x; ls -ld '$File::Find::name'";
           system "set -x; ls -Lld '$File::Find::name'";
           die "BUG";
         }
       },
     },
     $d
);
print "Test passed.\n";

-----------------------------------------------------------------
---
Flags:
    category=library
    severity=low
    module=File::Find
---
Site configuration information for perl 5.14.2:

Configured by Debian Project at Thu Jul 18 22:04:35 UTC 2013.

Summary of my perl5 (revision 5 version 14 subversion 2) configuration:
   
  Platform:
    osname=linux, osvers=3.2.0-37-generic, archname=x86_64-linux-gnu-thread-multi
    uname='linux roseapple 3.2.0-37-generic #58-ubuntu smp thu jan 24 15:28:10 utc 2013 x86_64 x86_64 x86_64 gnulinux '
    config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Dldflags= -Wl,-Bsymbolic-functions -Wl,-z,relro -Dlddlflags=-shared -Wl,-Bsymbolic-functions -Wl,-z,relro -Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.14 -Darchlib=/usr/lib/perl/5.14 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.14.2 -Dsitearch=/usr/local/lib/perl/5.14.2 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/man3 -Duse64bitint -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm -Uusesfio -Uusenm -Ui_libutil -DDEBUGGING=-g -Doptimize=-O2 -Duseshrplib -Dlibperl=libperl.so.5.14.2 -des'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fstack-protector -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2 -g',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fstack-protector -fno-strict-aliasing -pipe -I/usr/local/include'
    ccversion='', gccversion='4.8.1', gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /usr/lib
    libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
    perllibs=-ldl -lm -lpthread -lc -lcrypt
    libc=, so=so, useshrplib=true, libperl=libperl.so.5.14.2
    gnulibc_version='2.17'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib -fstack-protector'

Locally applied patches:
    

---
@INC for perl 5.14.2:
    /home/jima/lib/perl
    /home/jima/perl5/lib/perl5/x86_64-linux-gnu-thread-multi
    /home/jima/perl5/lib/perl5/x86_64-linux-gnu-thread-multi
    /home/jima/perl5/lib/perl5
    /etc/perl
    /usr/local/lib/perl/5.14.2
    /usr/local/share/perl/5.14.2
    /usr/lib/perl5
    /usr/share/perl5
    /usr/lib/perl/5.14
    /usr/share/perl/5.14
    /usr/local/lib/site_perl
    .

---
Environment for perl 5.14.2:
    HOME=/home/jima
    LANG=en_US.UTF-8
    LANGUAGE=en_US
    LD_LIBRARY_PATH=/home/jima/local/lib
    LOGDIR (unset)
    PATH=/home/jima/perl5/bin:/home/jima/bin:/home/jima/local/bin:/home/jima/jima_tools/x86_64/bin:/home/jima/jima_tools/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/bin/X11:/usr/local/bin:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/games:/usr/local/games:/usr/lib/jvm/java-7-oracle/bin:/usr/lib/jvm/java-7-oracle/db/bin:/usr/lib/jvm/java-7-oracle/jre/bin:.
    PERL5LIB=/home/jima/lib/perl:/home/jima/perl5/lib/perl5/x86_64-linux-gnu-thread-multi:/home/jima/perl5/lib/perl5
    PERL_BADLANG (unset)
    PERL_LOCAL_LIB_ROOT=/home/jima/perl5
    PERL_MB_OPT=--install_base /home/jima/perl5
    PERL_MM_OPT=INSTALL_BASE=/home/jima/perl5
    SHELL=/bin/bash


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