allow non-string values (and arrays) in claim_mappings

I was asked to raise an issue here following a conversation in google groups.

I'm using 1.4, and have Azure OIDC authentication working. However, I cannot have any claim that is a non-string

so, for example , part of the returned jwt from azure has this

iat": 1587560836,
"nbf": 1587560836,
"exp": 1587564736,
"acct": 0,
"auth_time": 1587541385,

"email": "julian@nodeable.io",

and I wanted to store "exp" as part of the entity alias metadata . if I include {"exp":"exp"} as part of the claims_mapping, the authentication fails with

"error converting claim 'exp' to string"

IOW, any non-string claim can't be assigned in the claims_mapping option

The other problem as I mentioned was that I wanted to get the azure user groups of the user into the entity alias. Azure returns the groups as

groups: ["group1","group2"]

and again, if I try to put a {groups:groups} claim in the claims_mapping vault borks with a

"error converting claim 'groups' to string"

is there any template magic than can be applied to the claims_mapping or is it a limitation of vault ?

Start by tracing how claim_mappings handles the numeric exp claim and the groups array, using the reported "error converting claim ... to string" failures as the entry point. Determine the expected representation for non-string values and arrays, then verify that both types can be mapped into entity alias metadata without breaking existing string mappings.

Written by the indexing model from the issue text.