Firstly this is not the same as the rest endpoint, so please don't link to that documentation, the provided format does *not* work with the JIM JSON importer.
I have actually been able to successfully import the first value, but not the child. And it also forces garbage values to be created.
Successfully Setting Parent Value
Using Values Fails
Using the FieldName test value works, but when using the value name by text, you get an error (if that value was already defined in the select).
"customFieldValues":[
{
"fieldName":"Competency Area",
"fieldType":"com.atlassian.jira.plugin.system.customfieldtypes:cascadingselect",
"value":"ITOPS"
}
]
,
An error occurred while attempting to import value 'ITOPS' into the Custom Field 'Competency Area'.
And the ticket does not contain the value.
Using IDs works, with a twist
But if you use the ID of the value, it first creats that (bogus) value in the list, but then seems to look up the right value for the ticket.
"customFieldValues":[
{
"fieldName":"Competency Area",
"fieldType":"com.atlassian.jira.plugin.system.customfieldtypes:cascadingselect",
"value":["11058"]
}
]
,
The ticket gets assigned proper value

But a new bogus value is created in parent list

Setting the Child Value (failed attempts)
So I can deal with the cleanup to go through and remove the bougs list values. But I have tried many attempts to get the child value without much luck.
Total failures
"customFieldValues":[
{
"fieldName":"Competency Area",
"fieldType":"com.atlassian.jira.plugin.system.customfieldtypes:cascadingselect",
"value":[{"value":"11058","child":"11065"}]
}
]
,
"customFieldValues":[
{
"fieldName":"Competency Area",
"fieldType":"com.atlassian.jira.plugin.system.customfieldtypes:cascadingselect",
"value": {"value":"11058","child":{"value":"11065"}}
}
]
,
"customFieldValues":[
{
"fieldName":"Competency Area",
"fieldType":"com.atlassian.jira.plugin.system.customfieldtypes:cascadingselect",
"value": [{"value":"11058"},{"value":"11065"}]
}
]
,
Soft Failures (first value added, second ignored)
"customFieldValues":[
{
"fieldName":"Competency Area",
"fieldType":"com.atlassian.jira.plugin.system.customfieldtypes:cascadingselect",
"value":["11058","11065"]
}
]
,
"customFieldValues":[
{
"fieldName":"Competency Area",
"fieldType":"com.atlassian.jira.plugin.system.customfieldtypes:cascadingselect",
"value": ["11058",{"child":"11065"}]
}
]
,
Anyone successfully done this from the JSON importer?