| Subject: | Pointless use of `use lib qw(..)' |
Polluting the user's @INC is never a good thing. Here's the situation I
just ran into:
*) We have a Foo::Bar module, which lives in our project at lib/Foo/Bar.pm.
*) We also have a Test::Foo::Bar module, which is a thin wrapper around
Foo::Bar for unit test purposes. It lives, of course, at
lib/Test/Foo/Bar.pm.
*) Test::Foo::Bar, naturally enough, contains a `use Foo::Bar' line.
*) In lib/Test, there is a t/ subdir where there are unit tests.
*) I happened to be in lib/Test/t, running a unit test, which happened
to do a `use Test::Foo::Bar' (actually, it included something else which
did that, but same principle).
*) Because I was also doing a `use Data::Random', and because it just so
happened that my `use Data::Random' was before my `use Test::Foo::Bar',
when perl got to the `use Foo::Bar' inside lib/Test/Foo/Bar.pm, it
actually included itself.
*) With the result that lib/Foo/Bar.pm was never loaded and code started
failing in very odd ways.
*) As you can imagine, this took two engineers and a couple of hours to
track down.
So, besides the general rule that mucking with @INC for no particular
reason is a Bad Thing(tm), this is very specifically causing me some
heartburn at the moment. It seems like just removing the single line
`use lib qw(..)' from the top of Data/Random.pm would take care of the
problem.
Thanks for your attention.