Thursday, July 6, 2017

Moving away from Dist::Zilla @Basic

Today a got an issue registered at my distribution Linux::Info and decided to take a quickly look at it since it was quite a while since the last release.

The issue itself was not that interesting (looks like the distribution Pod could receive some more attention, which indeed I added), but also gave me a chance to try and add a cpanfile to it.

Some months ago I was notified that my distributions were not providing a cpanfile. I wasn't even aware what was it about and what I was missing.

The thing is that a cpanfile is just another way to declare the distribution dependencies. Not really interesting from this point of view.

The good part of it is to allow the developer to install the distribution without having to install Dist::Zilla (and it's quite large number of dependencies) before even being able to build the distribution (well, assuming that the distribution uses Dist::Zilla).

That means you can skip some minutes and download bandwitdh, ignoring whatever Dist::Zilla depends on. Which also means you can just git clone a Perl project and install the requisites automatically with cpanm with two steps:

  1. git clone
  2. cpanm --installdeps .
That's it! Well, almost, you might need to install cpanm first. And be sure to include the dot in the step 2, it matters.

If your distribution uses Dist::Zilla already, you can add the cpanfile automatically by just adding [CpanFile] to the dist.ini file. The plug-in does the rest for you. Almost.

In order to have this cool stuff available from your code repository, you will need to have the cpanfile available over there... that means you need to build the distribution and copy the file to the repository, where it is going to be source controlled as everything else.

To cover that, you can use Dist::Zilla::Plugin::CopyFilesFromBuild, another plug-in to make your life easier.

But if you have the [@Basic] declared at the dist.ini (as I did) to load the most basic Dist::Zilla plug-ins you need, you will have a nasty surprise:

[DZ] attempt to add cpanfile multiple times; added by: GatherDir (Dist::Zilla::Plugin::GatherDir line 100); CPANFile (Dist::Zilla::Plugin::CPANFile line 65)

And the distribution generation is aborted. I was able to even find a bug registered about that, but it is not really a bug after all: it happens because the GatherDir, automatically registered by [@Basic], is not configured to ignore the cpanfile over there.

I tried to to that, but instead of getting rid of the error, I got a lot more of them, all of them related to GatherDir. Don't know why, but I was able to fix by removing [@Basic] and putting only the plug-ins I was indeed using and the over automatically included by the bundle and adding the following two lines to configured GatherDir:

exclude_filename = cpanfile

So, fixing the errors were a nice side effect of review what I indeed need in my distribution in terms of plug-ins.

Bottom line: Dist::Zilla::PluginBundle::Basic is great to start from scratch, but keep in mind that once your dist.ini is not that "basic" anymore, you will need to start cutting-off plug-ins!

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