[perl #22236] File::Basename behavior is misleading

# New Ticket Created by  frederik@ugcs.caltech.edu 
# Please include the string:  [perl #22236]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt2/Ticket/Display.html?id=22236 >



This is a bug report for perl from frederik@ugcs.caltech.edu,
generated with the help of perlbug 1.34 running under perl v5.8.0.


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[Please enter your report here]

The File::Basename man page suggests that the basename and dirname
functions are compatible with the Unix shell commands. It is not
important for most purposes that these functions match the commands
exactly, however, for them to be useful for certain things, it is
important to preserve the invariant that $f and
dirname($f)."/".basename($f) refer to the same file, i.e. that when
the two functions are used together, no information about the file
location is lost. This invariant seems to hold for the Unix shell
commands, but not for the File::Basename versions:

$ dirname a/
.
$ basename a/
a
$ perl -e 'use File::Basename; print basename("a/"),"\n"; print dirname("a/"),"\n";'

.
$

Here $f="a/", and dirname($f)."/".basename($f)="./".

[Please do not change anything below this line]
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---
Flags:
    category=library
    severity=medium
---
Site configuration information for perl v5.8.0:

Configured by Debian Project at Mon Feb 17 13:43:44 UTC 2003.

Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.4.19-powerpc-smp, archname=powerpc-linux-thread-multi
    uname='linux voltaire 2.4.19-powerpc-smp #1 smp mon sep 9 09:11:02 edt 2002 ppc unknown unknown gnulinux '
    config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=powerpc-linux -Dprefix=/usr -Dprivlib=/usr/share/perl/5.8.0 -Darchlib=/usr/lib/perl/5.8.0 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.8.0 -Dsitearch=/usr/local/lib/perl/5.8.0 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Uusesfio -Uusenm -Duseshrplib -Dlibperl=libperl.so.5.8.0 -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 -DDEBIAN -fno-strict-aliasing -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O3',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing'
    ccversion='', gccversion='3.2.3 20030210 (Debian prerelease)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=4321
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=8
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lgdbm -ldb -ldl -lm -lpthread -lc -lcrypt
    perllibs=-ldl -lm -lpthread -lc -lcrypt
    libc=/lib/libc-2.3.1.so, so=so, useshrplib=true, libperl=libperl.so.5.8.0
    gnulibc_version='2.3.1'
  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 v5.8.0:
    /etc/perl
    /usr/local/lib/perl/5.8.0
    /usr/local/share/perl/5.8.0
    /usr/lib/perl5
    /usr/share/perl5
    /usr/lib/perl/5.8.0
    /usr/share/perl/5.8.0
    /usr/local/lib/site_perl
    .

---
Environment for perl v5.8.0:
    HOME=/home/frederik
    LANG=C
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/frederik/bin:/usr/X11R6/bin:/usr/local/bin:/usr/bin:/bin:/home/frederik/sbin:/usr/X11R6/sbin:/usr/local/sbin:/usr/sbin:/sbin
    PERL_BADLANG (unset)
    SHELL=/bin/bash

• [perl #22236] File::Basename behavior is misleading by perlbug-followup