from-json(string, fallback?) function not working as expected

[SavinayaShetty]

JSLT functions Document (ref link) states following about from-json(string, fallback?) function-

Parses the string as JSON and returns the result. If the string is null then the function will return null

EX: 1 - Working Fine
input:

{
   "displayText" : "Subscribe",
   "postback" : "{\"name\":\"John\",\"in_out\":\"in\"}"
}

template:
from-json(.postback, null)
output:

{
  "name" : "John",
  "in_out" : "in"
}

As per the template if the postback is not a valid json, it should return null. But in the following case, it is giving unusual output.
EX: 2 - Unusual output
input:

{
   "displayText" : "Subscribe",
   "postback" : "\"name\":\"John\",\"in_out\":\"in\""
}

template:
from-json(.postback, null)
output:
"name"

Is this a bug in 'from-json' function?

[larsga]

Yes, that's a bug. Thank you for reporting it so clearly.

Looks like when from-json is parsing the string it stops after "name" instead of reporting the parse error like it should.

[SavinayaShetty]

Yes. I checked the code, seems like the issue is from Jackson ObjectMapper itself,

JsonNode parsed = NodeUtils.mapper.readTree(json);

I'll read up on this and see what I can find out. Thanks.