Wrong interpretation of option in GetOptions()

[p5pRT]

Migrated from rt.perl.org#8044 (status was 'resolved')

Searchable as RT8044$

[p5pRT]

From welker@pdvp01.tfh-berlin.de

Created by welker@tfh-berlin.de

This is a bug report for perl from welker@​tfh-berlin.de,
generated with the help of perlbug 1.28 running under perl v5.6.0.

-----------------------------------------------------------------

#!/usr/bin/perl
#
# Calling program with option --a will not set $opt_all, but $opt_a !!!!!
# welker@​tfh-berlin.de

use File​::Basename;
use Getopt​::Long;

$prog=basename $0;
$syntax = "Syntax​: $prog [-al] [--all]\n";

Getopt​::Long​::Configure ("require_order", "bundling", "auto_abbrev", "debug");
GetOptions("l", "all", "a") or die $syntax;

print "Option -a : $opt_a\n";
print "Option -l : $opt_l\n";
print "Option --all : $opt_all\n";

Perl Info

Flags:
    category=core
    severity=low

Site configuration information for perl v5.6.0:

Configured by root at Fri May 11 15:15:27 GMT 2001.

Summary of my perl5 (revision 5.0 version 6 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.4.3, archname=i586-linux
    uname='linux subbotin 2.4.3 #1 tue may 8 21:54:34 gmt 2001 i686 unknown '
    config_args='-ds -e -Dprefix=/usr -Di_db -Di_dbm -Di_ndbm -Di_gdbm'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
    useperlio=undef d_sfio=undef uselargefiles=define 
    use64bitint=undef use64bitall=undef uselongdouble=undef usesocks=undef
  Compiler:
    cc='cc', optimize='-O2 -pipe', gccversion=2.95.3 20010315 (SuSE)
    cppflags='-fno-strict-aliasing -I/usr/local/include'
    ccflags ='-fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    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, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -ldl -lm -lc -lcrypt
    libc=, so=so, useshrplib=false, libperl=libperl.a
  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 v5.6.0:
    /usr/lib/perl5/5.6.0/i586-linux
    /usr/lib/perl5/5.6.0
    /usr/lib/perl5/site_perl/5.6.0/i586-linux
    /usr/lib/perl5/site_perl/5.6.0
    /usr/lib/perl5/site_perl
    .


Environment for perl v5.6.0:
    HOME=/usr1/doz/welker
    LANG=de_DE
    LANGUAGE (unset)
    LC_COLLATE=POSIX
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr1/doz/welker/bin:/usr/local/bin:/usr/bin:/usr/X11R6/bin:/bin:/usr/lib/java/bin:/usr/games/bin:/usr/games:/opt/gnome/bin:/opt/kde2/bin:.:/usr1/doz/welker/bin:.
    PERL_BADLANG (unset)
    SHELL=/bin/sh

[p5pRT]

From @sciurius

[Quoting Prof. Welker, on December 12 2001, 15​:45, in "[ID 20011212.002] Wr"]

# Calling program with option --a will not set $opt_all, but $opt_a !!!!!

Let's see...

Getopt​::Long​::Configure ("require_order", "bundling", "auto_abbrev", "debug");
You enable bundling, indicating that things like -al may be unbundled
in -a and -l.

GetOptions("l", "all", "a") or die $syntax;

I see three options​: 'l', 'a', and 'all'.

Calling with "--a" means​:

  A "--" starter, so no unbundling is done.
  "a" matches option 'a' completely, and 'all' partially, so option
  'a' takes precedence.

Hence, $opt_a is set. Surprising, maybe, but it behaves as it should.

If I change the documentation of the bundling setting as follows​:

  Enabling this option will allow single-character options to be
  bundled. To distinguish bundles from long option names, long options
  I<must> be introduced with C<--> and bundles with C<->.

  Note that, if you have options C<a>, C<l> and C<all>, and
  auto_abbrev enabled, C<-a> and C<--a> will both match the
  single-character option C<a>. C<-al> will be unbundled into C<-a>
  and C<-l>, while C<--al> will autocomplete to C<--all>.

Would that prevent the surprise?

-- Johan

[p5pRT]

From [Unknown Contact. See original ticket]

Prof. Welker <welker@​pdvp01.tfh&#45;berlin.de> wrote​:

# Calling program with option --a will not set $opt_all, but $opt_a!!!!!
# welker@​tfh-berlin.de

use File​::Basename;
use Getopt​::Long;

$prog=basename $0;
$syntax = "Syntax​: $prog [-al] [--all]\n";

Getopt​::Long​::Configure ("require_order", "bundling", "auto_abbrev", "debug");
GetOptions("l", "all", "a") or die $syntax;

print "Option -a : $opt_a\n";
print "Option -l : $opt_l\n";
print "Option --all : $opt_all\n";

Johan Vromans <jvromans@​squirrel.nl> wrote​:

If I change the documentation of the bundling setting as follows​:

Enabling this option will allow single-character options to be
bundled. To distinguish bundles from long option names, long options
I<must> be introduced with C<--> and bundles with C<->.

Note that, if you have options C<a>, C<l> and C<all>, and
auto_abbrev enabled, C<-a> and C<--a> will both match the
single-character option C<a>. C<-al> will be unbundled into C<-a>
and C<-l>, while C<--al> will autocomplete to C<--all>.

Would that prevent the surprise?

I had that figured out as​:
  Note that, if you have options C<a>, C<l> and C<all>, and
  auto_abbrev enabled, possible arguments and option settings are​:

  using argument sets option(s)
  ------------------------------------------
  -a, --a a
  -l, --l l
  -al, -la, -ala, -all,... a, l
  --al, --all all

(What actually caused me to look into the code is the (as I see it)
implementation decision of permitting options that are the initial
substring of another option and the resulting rule that a full
length match overrules the potential disambiguity. So, Johan, if
you're going to update, maybe this one as well?)

As I workaround to the initial problem, I'd consider

  Getopt​::Long​::Configure ( "auto_abbrev", "debug", "prefix_pattern=--"
);
  GetOptions( "all" ) or die $syntax;

  Getopt​::Long​::Configure ("require_order", "bundling",
"prefix_pattern=-");
  GetOptions("l", "a", ) or die $syntax;

which happens to handle --a as --all, but has to sacrifice require_order
in the first pass (or else --all wouldn't be found after -a/-l/-al etc.

HTH,
-Wolfgang

[p5pRT]

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