Fail on bad metadata

[bmschmidt]

Wax has constraints on metadata that users might not immediately notice--e.g., that ids cannot include a period or uppercase letters, and that certain fields have special meanings.

If these rules are violated, a site will build but break in unpredictable ways. Would you consider instead throwing an error that explains what needs to happen differently? I suspect this will save users time by helping them identify where things have gone wrong.

[bmschmidt]

A rider on this: the documentation is a little vague on what the special id fields are:

It includes:

• ['Some fields are needed for Jekyll and Wax, and should not be used in your metadata file. For example, Jekyll has rules for its date field. You should avoid this key and use _date, like in the example spreadsheet above.

• The fields thumbnail, full, and manifest (seen below) are generated by Wax when you process your collection images. You should not manually create these fields (unless you know what you’re doing!), and should avoid these keys in your metadata.

Best I can tell, there a few other special fields that should be added to this list:

• Like 'label', have a special meaning which you should understand:
  • order
• Like thumbnail and full, should not be included in your input unless you completely understand what you're doing:
  • collection, layout.
• Whatever the special jekyll fields like "date" are.