Mapping None -> Null causes issues in some expressions

[pavanagrawal123]

This mapping is causing issues on the following expression:

$split(undefined, "-"), with a {} input, the reference implementation returns

While this library returns:
jsonata.jexception.JException: Argument None of Object None does not match Object signature which isn't the expected return value

edit: sorry, didn't spend too much time debugging, could also be stemming from this difference:

[rayokota]

I'm seeing

% echo '{}' | python3 -m jsonata.cli '$split(undefined, "-")'
None

[pavanagrawal123]

Ah sorry! I mixed up the offending expression. Here's the correct expression that is erroring:

echo '{}' | python3 -m jsonata.cli 'a ~> $split("-")'

JSONata error: Argument None of Object None does not match Object signature

versus the reference implementation:

[rayokota]

That's the same result as

echo '{}' | python3 -m jsonata.cli '$split(null, "-")'
JSONata error: Argument None of Object None does not match Object signature

I think this may be a bug in the official implementation. The specification for split says It is an error if str is not a string.

This is similar to the specification for trim which says An error is thrown if str is not a string. When you call trim(null) in the official implementation, you get Argument 1 of function "trim" does not match function signature

[pavanagrawal123]

The playground also appropriately throws an error here on $split

It doesn't here.

In the example of a ~> $split("-") the lhs is not a null value, but rather undefined. Seems like the reference implementation is treating null values differently than undefined values. That very well could be a bug in jsonata itself, since it's not clear that undefined values should be treated differently than null values.

Perhaps the - typing on the first arg input implies that an undefined is fine, but removing it in the js library, continues to not throw an error. Going to close this issue, since seems likely this is probably an implementation gap in jsonata.

Thanks for helping debug and writing such an amazing port, huge kudos 🎉 !

[pavanagrawal123]

Well -- digging a little further:

I believe that there is a pretty clear bug here:
The reference implementation chooses to return undefined for undefined $split inputs:

The python implementation also makes the same choice:

However, after evaling the ~>, the undefined value gets turned into a null here:

Because the undefined becomes a null the Python implementation throws an error, while the jsonata.js version does not.

[rayokota]

@pavanagrawal123 , please try v0.3.0

[pavanagrawal123]

Amazing, thanks so much @rayokota!