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Postings from January 2005
kane@coke.xs4all.nl (via RT) wrote:
> package core;
> use strict;
> sub import {
> require lib;
> lib->import( sub { eval q[*UNIVERSAL::VERSION = $old_version] })
> }
> 1;
Examining the code in Module::Build::Base, I can see why this would coredump,
since you stripped out all of the important bits. Effectively you are nuking
the &UNIVERSAL::VERSION subroutine. To quote the original code:
# version.pm will change the ->VERSION method, so we mitigate the
# potential effects here. Unfortunately local(*UNIVERSAL::VERSION)
# will crash perl < 5.8.1.
my $old_version = \&UNIVERSAL::VERSION;
eval {require version};
my $result = eval $eval;
*UNIVERSAL::VERSION = $old_version;
Here, $old_version is a reference to the original &UNIVERSAL::VERSION sub and it
is being captured before attempting to load the compatibility version.pm module,
then restored afterwords.
However, in your code, you are assigning a null scalar to the glob, thuse wiping
out the &UNIVERSAL::VERSION sub. The next module to be use'd will henceforth
call an null sub and blow bits all over the place.
If you tell me what you are actually attempting to do, I might be able to
suggest something different. I disagreed with the way that M::B was changed as
described in the comment above, so it may be that this issue will have to be
reopened with the M::B folks. If this is related to the laudable attempt to
move M::B into the core, the above code will have no effect whatsoever, since
the version.pm module is a stub in 5.9+; all of the UNIVERSAL::VERSION changes
are in the core already.
John
--
John Peacock
Director of Information Research and Technology
Rowman & Littlefield Publishing Group
4720 Boston Way
Lanham, MD 20706
301-459-3366 x.5010
fax 301-429-5747
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