Prevent mixing different versions of joi schema types

[kanongil]

Context

• joi version: @hapi/joi@16.0.0-rc2 & joi@14.3.1

What are you trying to achieve or the steps to reproduce ?

Validate old schema:

const Joi = require('@hapi/joi');
const Joi14 = require('joi');

const schema = Joi14.number();

console.log(Joi.validate(1, schema));

Which result you had ?

/Users/gil/test/joi/node_modules/@hapi/joi/lib/cast.js:73
        throw err;
        ^

AssertionError [ERR_ASSERTION]: Cannot add other alternatives without at least one schema(_tests)
    at new AssertionError (internal/assert.js:269:11)
    at Object.exports.assert (/Users/gil/test/joi/node_modules/@hapi/hoek/lib/index.js:592:11)
    at internals.Alternatives.try (/Users/gil/test/joi/node_modules/@hapi/joi/lib/types/alternatives.js:104:14)
    at Object.exports.schema (/Users/gil/test/joi/node_modules/@hapi/joi/lib/cast.js:31:42)
    at internals.Object.keys (/Users/gil/test/joi/node_modules/@hapi/joi/lib/types/object.js:401:35)
    at Object.exports.schema (/Users/gil/test/joi/node_modules/@hapi/joi/lib/cast.js:42:29)
    at Object.internals.appendPath (/Users/gil/test/joi/node_modules/@hapi/joi/lib/cast.js:66:24)
    at Object.exports.schema (/Users/gil/test/joi/node_modules/@hapi/joi/lib/cast.js:15:26)
    at module.exports.internals.Any.root.compile (/Users/gil/test/joi/node_modules/@hapi/joi/lib/index.js:176:21)
    at module.exports.internals.Any.root.validate (/Users/gil/test/joi/node_modules/@hapi/joi/lib/index.js:161:29)

What did you expect ?

Either a successful validation by calling into the old joi logic, or a more descriptive thrown error.

Note that this is the way that Hapi currently validates schemas in routes, causing such an error whenever an old schema is passed.

[hueniverse]

I am going to change the way hapi uses joi to compile provided schemas. This has been a PITA for a long time, requiring breaking hapi releases for joi updates.