F# DataContractJsonSerializer StackOverflowException

Question

dataElementsList : TypesAndData.DataElement list

is a list of 50,000 records (actually many more but let's start small). I am trying to serialize to a JSON file:

let ser = Json.DataContractJsonSerializer(typeof<TypesAndData.DataElement list>) 
use ofs = File.OpenWrite(fileName)
let result = ser.WriteObject(ofs, dataElementsList)

and am getting the infamous StackOverflowException. to be precise:

An unhandled exception of type 'System.StackOverflowException' occurred in FSharp.Core.dll

any advice?

Answer 1

You should not try to serialize an F# list this way. Convert it to an array with List.toArray.

(I expect that the DataContract serializers see lists as nested 'first'/'rest' data structures, which means 50000 tree depth of Json/Xml, which is not what you want.)