Is my JSON incorrectly formatted?

[R. Simpson]

I am POST'ing the following data to our server's v2 API using Python's request library.

{
"fields": {
   "customfield_10300": "8lbs 3oz",
   "customfield_10315": {
      "value": "Mississippi",
      "child": "Harrison"
   },
   "project": {
      "key": "BOD"
   },
   "issuetype": {
      "name": "Task"
   }
}
}

I get an error:

{
"customfield_10315": "Can not instantiate value of type [simple type, class com.atlassian.jira.issue.fields.rest.json.bean.CustomFieldOptionJsonBean] from JSON String; no single-String constructor/factory method (through reference chain: com.atalassianl.jira.issue.fields.rest.json.beans.CustomFieldOptionJsonBean[\"child\"])"
}

Is my JSON incorrectly formatted?
Where could I have gone to figure this out on my own? I unsuccessfully tried searching the documentation. I also tried googling a solution, but the results all seemed to indicate those people were double-encoding their JSON strings by accident, which I don't think I am doing.

[Thomas Deiler]

Dear @R. Simpson ,

updating custom fields can be tricky. what type of custom is customfield_10315? What's your REST endpoint?

So long

Thomas

[Bill Sheboy]

Hi @R. Simpson  -- Welcome to the Atlassian Community!

I noted that your project field name is not enclosed in quotation marks.  Have you tried to add those?

Best regards,

Bill

[R. Simpson]

Apologies:  that was a typo.

[Bill Sheboy]

Gotcha, and thanks. A few more ideas:

You may want to check out the REST API call to create issue, which uses the ID values rather than the names for such JSON access.  I cannot tell what transaction you are calling to know if that is relevant:

https://docs.atlassian.com/software/jira/docs/api/REST/1000.824.0/#api/2/issue-createIssue

Next, to confirm you are accessing the correct smart values/field names, you could make a call to the REST API with an example issue to check.  Here's an explanation of that:

https://support.atlassian.com/jira-software-cloud/docs/find-the-smart-value-for-a-field/