RFC: Add Mustang to the gem?

[halfbyte]

So, after having to solve a couple of hairy validation issues lately, I came to the conclusion that the official Factur-X schemas are more or less useless in that they do not test a lot of the business rules defined in the documentation.

Mustangproject.org's Mustang-CLI does a much better job, at the expense of being somewhat massive. It is, though, somewhat of a Factur-X swiss army knive and can attach XML to PDF's (Which would address #12).

It would increase the size of the Gem about x10, with the JAR clocking in at around roughly one Chromium (70MB). This feels a bit excessive.

Alternatively, I could add a script that would download the latest known working Mustang version and install it, but this would break in systems like Nix where the gem ends up in a read only file system. We could introduce an environment variable pointing to the JAR path.

Anyone any better ideas?

[sebastianludwig]

The idea would be to use Mustang as validation tool for the unit tests or in production?

[halfbyte]

@sebastianludwig I'm leaning towards not including it but requiring it for testing. I think it would be useful to have a Mustang adapter for validations, as it is by far the most useful tool for validation, but I don't really know how many of you are actually validating stuff in production.

I'l have another round of thinking about this :)