Ensure that ujson.Value behaves properly as a direct target of reading/writing

[lihaoyi]

The basic issue is that the StringVisitor/StringReader used for processing map keys when building JSON ASTs (

upickle/ujson/src/ujson/AstTransformer.scala

Line 30 in d0b618e

def visitKey(index: Int) = upickle.core.StringVisitor

) was not sufficiently forgiving in accepting non-string types, which can be given to it when serializing a map with non-string keys.

This "loosening" of the input handling is in line with the general trend throughout uPickle, similar to how in 2.0.0 we allowed #385 we allowed numeric Scala types to accept JSON strings as input

This PR adds it to the test suite conversion matrix, so this code path is additionally exercised for every value in our test suite, and fixed another bug uncovered that crashed when directly writing Infinity and -Infinity to ujson.Value

Fixes #433

[lefou]

Looks reasonable to me. The binary breakage is ok here, but it's interesting, that it only breaks for Scala.js.

[lefou]

Looks reasonable to me. The binary breakage is ok here, but it's interesting, that it only breaks for Scala.js.

Oh, it runs without --keep-going, so it probably also fails for all other platforms.

[lihaoyi]

We're going to release 3.0.0 next anyway right? which would mean binary compat breakage doesn't matter?

[lefou]

We're going to release 3.0.0 next anyway right? which would mean binary compat breakage doesn't matter?

Exactly. The whole point about the 3.0.0-M1 pre-release was to get some binary breaking things in.