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Re: List of modules I need


Richard Holland <holland@eaglegenomics.com> writes:

>>>>> * LWP::Parallel::UserAgent
>>>>>   (depends on the special case above)
>> Is this the only reason why you need the old version of libwww-perl or
>> are there other incompatibilities?
> I believe this is the main reason. LWP:: Parallel:::UserAgent is used
> extensively throughout Ensembl code. (Did some double-checking and
> apparently libwww-perl 5.812 will also work, but its still very old
> and also not in Debian).
> Would it work if I simply packaged LWP::Parallel::UserAgent and the
> dependent version of libwww-perl into the Ensembl .deb, in a
> subdirectory of the Ensembl install location (clearly distinguishing
> the licences and sources of course, and naturally checking the
> licences of both first to see if this is permissible). This is the
> same way that BioPerl gets integrated. That way the old code could
> stay inside the Ensembl install location and only be used by Ensembl
> itself, as it would be configured to use its own Perl modules, where
> present, in preference to system ones.
> Or are there drop-in alternatives to LWP::Parallel::UserAgent in
> Debian that I could use instead? (without having to modify any Ensembl
> code.)

Packages embedding other libraries are a problem for Debian in various
ways.  It makes support much harder as all copies have to be located,
checked, patched (different versions may require different patches) and
tested.  This easily makes much work for the security team and
complicates transitions (like the one to perl 5.12 mentioned below).
For this reason this practice is advised against (see Policy 4.13 [1])
and regarded as a bug (see [2] for a list of known embedded code copies;
many have an associated bug report).

Furthermore packages using embedded copies do not profit from further
development, including bug fixes and new features.  BioPerl-1.2.3 was
released almost seven years ago [3], BioPerl-1.4 in December 2003.

In the case of LWP::Parallel::UserAgent, the module needs to be fixed
anyway as reports on CPAN's Request Tracker [4] indicate that it breaks
with perl 5.12.1.  I don't know of any drop-in replacements, but there
is at least libpoe-component-client-http-perl which should be able to
download several files via HTTP in parallel (I have not used it myself
though, no idea how different this is).


[1] <http://www.debian.org/doc/debian-policy/ch-source.html#s-embeddedfiles>
[2] <http://svn.debian.org/wsvn/secure-testing/data/embedded-code-copies>
[3] <http://github.com/bioperl/bioperl-live/tree/bioperl-release-1-2-3>
[4] <https://rt.cpan.org/Public/Bug/Display.html?id=40261>

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