fix(schema): Deprecated setting schema paths to primitive values

[lpizzinidev]

fix #7558

Summary
Prevent setting a Schema path to a boolean value by throwing an error.
The issue refers to primitive types in general, let me know if the check needs to be extended to other types or refactored in some way.

[hasezoey]

i am not too familiar with the code in question, but couldnt we just check !(typeof type === "function" || typeof type === "object") (or just remove the function check if evaluated before the error) or just simply try to check against Schema.Types.* first, then all primitive constructors (like String, Buffer, etc) in a if-else or via a tracking variable and if none of them matches give a warning (/ throw a error in a new major)?

also you may want to change it to deprecation warning instead of error for the 6.x branch and a error for 7.x (next major) or directly target the 7.x branch

[AbdelrahmanHafez]

LGTM, thanks. 👍

[vkarpov15]

Change this to key !== '_id' && ((typeof val !== 'object' && typeof val !== 'function') || val == null). Not sufficient to check for boolean, we want to disallow all primitives.

[lpizzinidev]

👍 I've added an extra case to handle primitives specified as strings, otherwise, tests like this were failing.

[vkarpov15]

Thanks 👍