How to retrieve allowed values in JIRA 2 custom fields

[vengala rao]

 Based on the reply in this thread below I can retrieve all fields in relation to projectName and IssueType: https://community.atlassian.com/t5/Jira-questions/How-do-I-get-all-custom-fields-of-an-issue-using-rest-api/qaq-p/538525

However I'm not getting allowed values for all custom fields (For some custom fields It's returning allowed values and for other fields even though there are allowed values It's not returned in reply)? Also If a custom field's allowed values are dependent on another custom field selection how to retrieve those values?

Also from the above reply how to know that a custom field allowed values is dependent on another custom field selection?

[Alexey Matveev]

Hello,

There is only one custom field type in the out of the box Jira, which has dependent values: cascading select. But actually it is one custom field. It is only represented on the screen as two dropdowns.

What are the custom field types, for which you can not see allowed values? What are the custom field types for the dependent custom fields?

[vengala rao]

We're using enterprise edition and I believe the admin has the ability to set custom fields based on project requirements.. I can see the allowed values when I try to use the jira dashboard create JIRA option but not when consuming JIRA API(using createMeta?)..

Basically the Admin can specify custom fields and by making a call similar to this: https://jira.atlassian.com/rest/api/latest/issue/createmeta?projectKeys=JRA&issuetypeName=Bug&expand=projects.issuetypes.fields we're getting fields info.

1) How can i retrieve custom fields relation (Custom Field 2 allowed values dependent on custom Field 1 selection like that) ? 

2) Also as I was mentioning some of the custom fields allowed values are not available.