JSONFormat.defaultFormat doesn't handle null values

[scabug]

import scala.util.parsing.json.JSONObject
println(new JSONObject(Map("test" -> null)))

will throw an exception:

java.lang.NullPointerException
        at scala.util.parsing.json.JSONFormat$$anonfun$1.apply(Parser.scala:59)
        at scala.util.parsing.json.JSONFormat$$anonfun$1.apply(Parser.scala:55)
        at scala.util.parsing.json.JSONObject$$anonfun$toString$1.apply(Parser.scala:96)
        at scala.util.parsing.json.JSONObject$$anonfun$toString$1.apply(Parser.scala:96)
        at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:194)
        at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:194)
        at scala.collection.immutable.Map$Map1.foreach(Map.scala:118)
        at scala.collection.TraversableLike$class.map(TraversableLike.scala:194)
        at scala.collection.immutable.Map$Map1.map(Map.scala:106)
        at scala.util.parsing.json.JSONObject.toString(Parser.scala:96)
        at scala.util.parsing.json.JSONType.toString(Parser.scala:33)
        at java.lang.String.valueOf(String.java:2826)
        at java.io.PrintStream.println(PrintStream.java:771)
        at scala.Console$.println(Console.scala:244)

This is works in 2.8, so it's clearly a regression.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-5092?orig=1
Reporter: Zsombor Gegesy (gzsombor)
Affected Versions: 2.9.0, 2.9.1, 2.9.2
See #6571

[scabug]

David Leppik (dleppik) said:
It appears that the problem is that scala.util.parsing.json.JSONFormat (line 55 in Parser.scala) is missing one case, which should be:

case null => "null"

This is important to fix, since nulls are commonly used in JSON, including in third-party JavaScript libraries, so proper handling of nulls is necessary. (A more Scala-ish solution would be to format None as null, and then parse JSON nulls into None.)

[scabug]

@adriaanm said:
see #6571 (planning to deprecate in 2.11)

[scabug]

@adriaanm said:
json parsing has been deprecated in the parser combinators library -- please use spray-json, play-json,...

[scabug]

ChangZhuo Chen (陳昌倬) (czchen) said:
What is the status of this issue?

The deprecated annotation is removed in [0], and #6571 said "closing as meta-bug – the individual tickets will still be fixed if they haven't already". However, this issue still happens in Scala 2.10.5. So I am not sure it is deprecated or revived right now? Please provide the information so that we can decide continuously use it or change to third-party library, thanks.

[0] scala/scala-parser-combinators@ff68f4b

[scabug]

@adriaanm said:
I would not recommend using the json parser in scala-parser-combinators. Which alternative is suitable for you depends on your requirements -- there are almost too many to name. Here's a good overview: https://github.com/propensive/rapture-json

[scabug]

@soc said:
I have no idea why it was undeprecated, I even explicitly wrote that instead of undeprecating the JSON part, the rest which hasn't been deprecated yet should also be deprecated, and people agreed. (scala/scala-parser-combinators#32)

Maybe the merge was an oversight?

[scabug]

@adriaanm said:
Sounds likely to be a mistake, yes.