New class assigned to $*ARGFILES breaks "IO::CatHandle::Autolines"

[JJ]

The Problem

IO::CatHandle::Autolines rely on $*ARGFILES being a IO::ArgFiles; it's now become a IO::Handle, at least in the default case.

That causes a number of issues in that module (from 2020.01) as well as derived modules (such as LN, making them fail tests.

Expected Behavior

I guess that was not spec, but there was no warning in the changes either, except for this one:

$*ARGFILES special variable now defaults to $*IN if no arguments [bde1069]

I guess that the problem is that it bounds to $*IN, instead of containing $*IN (but I could be wrong, of course).

The behavior is not a problem per se, but this new behavior should maybe be tested either locally here or in roast, so that we don't break stuff that relies on it later on.

Environment

Tested with 2020.01 and 2020.02

[lizmat]

Technically, this is not a Rakudo issue. The module uses Rakudo internals information, and that can change without notice. As has happened. This thing is, that change was made to get better performance in the simple case. I don't think it is wise to revert that change, and make every user suffer from performance degradation, just to make this special case work again.

I am now looking at upgrading the module in such a way that it can be used before and after the breaking change in Raku.

[JJ]

El vie., 13 mar. 2020 a las 18:33, Elizabeth Mattijsen (< notifications@github.com>) escribió:

Technically, this is not a Rakudo issue. The module uses Rakudo internals information, and that can change without notice. As has happened. This thing is, that change was made to get better performance in the simple case. I don't think it is wise to revert that change, and make every user suffer from performance degradation, just to make this special case work again.

Of course. It doesn't make a lot of sense.

I am now looking at upgrading the module in such a way that it can be used before and after the breaking change in Raku.

That would be great. But another option is simply refactoring the using module; that particular thing is used for a feature which I don't really find that useful. I really just found out because the downstream module was mentioned in StackOverflow, and was curious as to its state... But it would be great, of course, if it continued working the way it did.

[lizmat]

The updated versions of IO::CatHandle::AutoLines and LN now work transparently with older as well as newer versions of Rakudo. So I think we can close this ticket.