blogs.perl.org

Over the past year, I’ve been self-studying XS and have now decided to share my learning journey through a series of blog posts. This second post introduces the fundamentals of type checking variables in XS.

Map::Tube now supports Unicode character in station names.
Please check out the link below for more information.
https://theweeklychallenge.org/blog/map-tube-unicode

We were all present.

• CVE-2024-56406 is published and has been addressed by new point releases. Please upgrade or patch your perl promptly if affected. We thank Steve Hay, Andreas König and Stig Palmquist for doing the heavy lifting, as well as Nathan Mills for discovering the problem, and Karl Williams for providing the fix. We re-/learned a number of old and new lessons about the handling of security issues, which we will write up as new process for the PSC, the Perl Security Team, and the CPANSec group, to be jointly reviewed and agreed at the looming PTS.

• We started winnowing this release cycle’s pull requests for potential release blockers. We briefly reviewed all 72 pull requests and identified 11 of interest for a closer look.

• We reviewed the 2 new issues filed since last week for release blocker potential and put one of them on our list for closer review. We then started a closer examination of the 20 issues we identified as candidate blockers. We got through 5 issues, none of which we considered blockers.

[P5P posting of this summary]

Years ago I wrote about a concise fork idiom. It turns out that it’s possible to do better than everything I discussed in that entry as well as the proposals in the comments.

I didn’t at the time appreciate a clever aspect of variable scoping in Perl:

use strict;
sub get_answer { 0 }
if ( my $answer = get_answer ) {
    ...;
} else {
    print $answer;
}

So, what exactly is a Readonly variable in Perl? A readonly variable is one that, once assigned a value, cannot be changed. Any attempt to modify it will trigger a runtime error. This mechanism enforces immutability, ensuring that critical values remain untouched and are protected from accidental or unauthorised alterations.

Couple of experimental features added to Map::Tube.
Please check out the link below for more information.
https://theweeklychallenge.org/blog/map-tube-experimental

App::ModuleBuildTiny is a relatively new authoring tool. It aims to be a relatively lightweight (at least to some other tools like Dist::Zilla) and newbie friendly tool. It supports two install tools: Module::Build::Tiny (obviously what it was originally designed for) and Dist::Build; it does not support ExtUtils::MakeMaker or Module::Build.

All three of us attended, but none of us had the time for significant discussion, so we decided to reclaim the time and make some progress on our various to-do list items.

[P5P posting of this summary]

(apologies for "promoting"(?) Perl obfuscation...)

Today I won a gift card at an in-office meeting with the following code. Challenge: print the numbers 1-100 in the most incomprehensible, inefficient way. My entry, edited for brevity:

#!/usr/bin/env perl
use v5.16;
splice @_, @_, -1, ++$_;
splice @_, @_, -1, ++$_;
splice @_, @_, -1, ++$_;
splice @_, @_, -1, ++$_;
splice @_, @_, -1, ++$_;
# plus 95 more of this
say join $/, @_;

Thinking about it more this evening, I came up with

$SIG {__DIE__} = sub { $_ = (pop)+0; chomp; $_%6?say:exit};
{ select undef,undef,undef,1; eval { die time-$^T }; redo; }

(where 6 instead of 101 so I don't have to wait 100 seconds (and to be honest I'm not sure if there'll be rounding errors)).

Wonder if any obfuscators could come up with better (the less inefficient, incomprehensible the better).

Find out all about CVE and how we deal with it in Perl.
Please checkout the post for more information:
https://theweeklychallenge.org/blog/cve-in-perl

I wrote very elliptically about this warning and received some helpful comments with the standard advice about how to proceed when encountering it. Except unfortunately that advice will be of no use when you encounter this warning.

Namely I should have been less cute about it and made it clear that I was specifically talking about a warning about a wide character “in substitution”. How can a s/// even possibly trigger a wide character warning, you ask? Beats me, to be entirely honest, even now, but: if you have a use locale somewhere, it turns out that it can. Because defeating that is what fixed the warning I was getting:

The three of us attended.

• Preparations for the point release are now in full swing.
• In relation to that, we ran into infrastructure permissions discrepancies that have cropped up due to an absence of onboarding/offboarding procedures. We need to address both the immediate and long-term issues here.
• We started winnowing this release cycle’s issues for potential release blockers. Out of about 95 issues, we have so far reviewed half, of which we identified 8 of interest. Additionally there are 72 pull requests to review.

[P5P posting of this summary]

Control. That’s what we all desire and very rarely acquire. The natural restlessness that occurs when you watch one of your offspring flicking from one movie title to the next, barely glancing at the summary before rejecting it, is one of the reasons I don’t like family movie night. My daughter’s grip on the remote is as strong as her decision making skills are weak; I struggle silently to hold back any outburst that would expose my failing parenting abilities once again. I have to distract myself with thoughts of the good old days when the TV had only 4 channels and Teletext was the closest thing to internet. Desiring such regression is now getting much of a habit for me. But we change what we can, accept what we can’t and trust, often foolishly, that those blessed with control do the best for all of us. Ah, look. Another teen fantasy horror romance movie. Thanks a heap, Netflix.

An introduction to newbie in Perl.
Please checkout the post for more information:
https://theweeklychallenge.org/blog/welcome-to-perl

Herewith V 1.24

Cheers

We didn’t have a meeting last week. This week, everyone was here.

• We briefly talked about builtin. We think a numify function is quite necessary.
• We started reviewing release blockers for v5.42.

[P5P posting of this summary]

In the last months of the previous century, I had to learn Perl to be able to teach it to professionals. It was my 28th language to use, but still took two years to understand deeply. As experienced assembler and C programmer, I was astound how much more of my ideas I could achieve with this new Swiss army knife in my hands. I fell in love with Perl.

Of course, the only way to learn a programming language well, is to use it for a larger project. So, I started to re-code the business shell scripts and websites to Perl. Part of it was sending automated emails to colleagues.

Your phase in life is probably different, but for my personal feeling it was not too long ago; for Internet's lifespan, the year 2000 is ancient history. The first spec for MIME headers in email were just 8 years old at the time, and many email features were still evolving.

Handling of undef / false default values in Perl v5.38
Please checkout the post for more information:
https://theweeklychallenge.org/blog/subroutine-signatures

sub some_field : lvalue { state $value = 'some_default' }

(We know, of course, that “class data” is OOPese for “global variable”.)

All three of us attended. Other than administrivia we talked about formally documenting our supported platforms, and we intend to start a discussion on the mailing list about this soon. This is also a topic for the upcoming Perl Toolchain Summit.

[P5P posting of this summary]