Error messaging when you attempt to set reserved Eleventy Data names

[Dexus]

I would like to see a Documentation with alle reserved variables like page && page.xxx or content if you use it with markdown and a layout file in nunjucks or something else.

It is difficult to find all the reserved variables, and it looks like if I use them as file in _data folder, it will not merged or respected.

[zachleat]

https://www.11ty.dev/docs/data-eleventy-supplied/ does exist

Going a little further, I think we should add some error messaging if you try to set one of these. I’m going to swap this issue to include that as well.

One of these issues is using alias: page with pagination (see #2161 (comment))

[zachleat]

Swapping to bug behavior. Some of this work is finished to freeze the pkg and eleventy properties in global data in this branch: https://github.com/11ty/eleventy/tree/frozen-reserved-data

We’ll give an escape hatch here to let folks disable this behavior in configuration: eleventyConfig.setFreezeReservedData(false);

More to come!