Any ideas what this error is trying to tell me? Google doesn't help and if the field "Values" referenced in the error is some mandatory parameter then it doesn't seem to be documented in https://www.pulumi.com/docs/reference/pkg/aws/iam/getpolicydocument/

That is a very strange error message - but Pulumi invoke function like

get_policy_document

don't accept

Output[T]

values as inputs, only raw strings and such, so the

user.arn.apply(lambda arn: arn)

above looks likely to be problematic. The typical approach is to call

get_policy_document

inside the

apply

. Which is typcially done by creating a helper function that will call this function with the real

str

value, and passing that function to

apply

.