Setting `"production"` in META6.json may be deprecated

[schultzdavid]

fez at least throws this warning when uploading a distribution whose META6.json contains "production": true or false:

=<< WARN: "production" in META is deprecated. Please create a .fez file with the json object
            {"production":false}
          to continue using this functionality after v53

I'm not sure if this deprecation is just a decision by fez, or if it does reflect a decision about META6.json in general. It could also be that the production setting was entirely fez-specific from the start: The Raku docs and roasts never mention it; in particular, it's absent in this example META6.json. (The diff in fez that introduced this deprecation warning 3 years ago doesn't give an explanation.)

Anyway, if the goal is for the META module to work completely smoothly with fez, it appears one would need to:

• Deprecate setting production => False in META6 objects, and remove such lines from code examples

One might also

• create an option for META6 objects to include fez-specific settings, so that the .fez file suggested in the warning could be generated from them as well. Perhaps using prefixed names for these attributes (e.g. __fez_production) and/or an adverb in the constructor. (Not sure if something like this is a good idea, though.)

[jonathanstowe]

This was based on the original spec at https://github.com/Raku/old-design-docs/blob/master/S22-package-format.pod . The difficulty with this is that there isn't really a canonical live specification despite there being many conversations about it, so we have a situation whereby people create de facto versions of the specification by usage.

The attribute itself is marked as optional with no default and won't be output when serialized to JSON if it hasn't been explicitly set.

I'm a bit surprised at fez even caring about it to be honest as it's more an install time thing, I think I need to find more out about the rationale. Having looked at the code it seems that it just won't upload the package if production is set to False,

I don't know if I would be inclined to make the attribute deprecated in META6, as it is entirely possible that it is being used without fez being involved. I would tend toward extending the annotation such that Test::META can warn or fail (or ignore,) things that other software doesn't like, with appropriate switches. Though removing them from the examples is fine (I'm not convinced it's actually used anywhere.)

I wouldn't want to put fez specific stuff in the module (with the exception perhaps of the annotations;) I would see that being responsibility of some notional module that might manage the META6.json for various purposes.