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Postings from November 2003
On Tue, Nov 04, 2003 at 03:26:16PM +0000, Tim Bunce wrote:
> I'm not convinced. Here's the code for can() that's embedded into the DBI
> dispatcher:
The existence of UNIVERSAL::AUTOLOAD is definately interfering. Here's an
example of running the test with a UNIVERSAL::AUTOLOAD that should be
transparent.
$ cat /tmp/lib/Foo.pm
package Foo;
use Carp;
sub UNIVERSAL::AUTOLOAD {
my $proto = shift;
my $class = ref $proto || $proto;
my($method) = $UNIVERSAL::AUTOLOAD =~ /([^:]+)$/;
croak qq{Can't locate object method "$method" via package "$class"};
}
1;
$ perl5.8.1 -I/tmp/lib -MFoo -Mblib -w t/01basic.t
1..43
ok 1 at line 32
ok 2 at line 33
ok 3 at line 37
(in cleanup) Can't locate object method "DESTROY" via package "IO::Handle" at t/01basics.t line 39
ok 4 at line 40
ok 5 at line 41
(in cleanup) Can't locate object method "DESTROY" via package "IO::Handle" at t/01basics.t line 44
ok 6 at line 45
...normal test output...
ok 39 at line 104
(in cleanup) Can't locate object method "DESTROY" via package "IO::Handle" at /usr/local/src/CPAN/DBI-1.38/blib/lib/DBI.pm line 930
ok 40 at line 108
ok 41 at line 109
(in cleanup) Can't locate object method "DESTROY" via package "IO::Handle" at /usr/local/src/CPAN/DBI-1.38/blib/lib/DBI.pm line 930
ok 42 at line 111
ok 43 at line 112
Can't locate object method "disconnect_all" via package "DBI::dr" at /usr/local/src/CPAN/DBI-1.38/blib/lib/DBI.pm line 653
END failed--call queue aborted.
(in cleanup) Can't locate object method "DESTROY" via package "DBI::dr" at t/01basics.t line 0
(in cleanup) Can't locate object method "DESTROY" via package "DBI::var" at t/01basics.t line 0
(in cleanup) Can't locate object method "DESTROY" via package "IO::Handle" at t/01basics.t line 0
The simplest bit to debug is the "disconnect_all" error. Simply fire up
the test with the debugger and "c DBI::disconnect_all". Once there
you can notice that can() says this:
DBI::disconnect_all(/usr/local/src/CPAN/DBI-1.38/blib/lib/DBI.pm:653):
653: $drh->disconnect_all() if ref $drh;
DB<2> x $drh->can('disconnect_all')
0 CODE(0x52387c)
-> &CODE(0x52387c) in ???
and that code ref isn't the UNIVERSAL::AUTOLOAD
DB<3> x $drh->can('AUTOLOAD')
0 CODE(0x2d70ec)
-> &UNIVERSAL::AUTOLOAD in /tmp/lib/Foo.pm:4-9
but when we step into $drh->disconnect_all()...
DB<4> s
UNIVERSAL::AUTOLOAD(/tmp/lib/Foo.pm:5):
5: my $proto = shift;
DB<4> T
$ = UNIVERSAL::AUTOLOAD(ref(DBI::dr)) called from file `/usr/local/src/CPAN/DBI-1.38/blib/lib/DBI.pm' line 653
$ = DBI::disconnect_all('DBI') called from file `/usr/local/src/CPAN/DBI-1.38/blib/lib/DBI.pm' line 477
$ = DBI::END() called from file `t/01basics.t' line 0
$ = eval {...} called from file `t/01basics.t' line 0
So something funky is going on. can() says there's a method defined but
when you actually call it it goes into AUTOLOAD. That ain't right.
Perhaps DBI's can() is reporting the empty disconnect_all() method but
your hacked^Waltered ;) method dispatcher is ignoring the empty subroutine
and falling back to AUTOLOAD?
--
Michael G Schwern schwern@pobox.com http://www.pobox.com/~schwern/
If it's stupid, but it works, it isn't stupid.
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