feat: ✨ handle grouped errors under the enum constraint

[martonvago]

Description

This PR handles grouped errors at $.resources[x].schema.fields[x].constraints.enum. It's the worst one yet!

This schema node is deeply nested, so handling errors here is a little more complex.

The situation is the following: for each field, you can list the allowed values for that field under "constraints": {"enum": [...]}. Depending on the type of the field, the type of the values in enum can be different. Sometimes it's straightforward (e.g. for string fields, enum values have to be strings), but sometimes the schema for enum is more permissive (e.g. for number fields, enum values can be either numbers or strings). However, you cannot mix types.

If enum has mixed types or if some of the values are the wrong type, all sub-schemas under enum flag errors. These are usually contradictory, e.g., for a number field [1, "inf"] will alert both because 1 is not a string and because "inf" is not a number...

The logic in the function:

• if the error is not even for the current field type -> remove all errors
• if there are any errors on the enum property itself (not an array, duplicate items, etc.) -> keep only these
• the remaining errors are all about the individual values in the enum array being the wrong type
  • if the values are not all the same type -> flag only this
  • if they are all the same type -> flag that this is the wrong type

Part of #15

Needs an in-depth review.

Checklist

• Formatted Markdown
• Ran just run-all

[martonvago]

E.g., for type checks, this would be the name of the type. I'm using this below to list the possible types for enum values in the error message.

[lwjohnst86]

Neat! Just some fairly small comments ☺️

[lwjohnst86]

What is the set() doing here? Why is it necessary?

[martonvago]

Because there can be more errors than allowed types.
E.g., if the allowed types are array and object and the enum array is [1, 2], then both enum items will cause errors for both allowed types. So 4 errors but only 2 allowed types.