Index variable value not shown when reporting "Invalid index" error

[jmouka]

Terraform Version

Terraform v1.4.6

Use Cases

When using a for_each and there is a missing or invalid index, Terraform should print out the actual value that's causing the issue. Instead the error is

Error: Invalid index
│   on ../modules/users/usersModule.tf line 117, in resource "okta_group_memberships" "mygroup":
│  117:   users = [for username in each.value.users: okta_user.users[username].id ]
│     │ okta_user.user is object with 727 attributes
│ The given key does not identify an element in this collection value.

Attempted Solutions

Basically I need to manually find the missing key. My terraform project has 727 values for this resource...

Proposal

It would be nice to see the actual resource ID, eg The given key "john123" does not identify an element in this collection value.

References

No response

[apparentlymart]

Hi @jmouka! Thanks for reporting this.

In what you showed here, I would've expected Terraform to mention the value as part of the summary of the relevant values in scope, like this:

│     │ okta_user.user is object with 727 attributes
│     │ user is "john123"

Of course, I can see that it didn't, and so I think my first priority here would be to try to understand why that didn't work and see if we can fix it.

Letting the general variable value listing handle this if possible is the most ideal approach because that component already knows how to deal with all of the edge cases of values, such as them being unknown or sensitive, so we don't need to have various different implementations of rendering a value in all of the possible different sentences it might need to appear in.

Of course we might find in investigating this that there's a good reason why user didn't show up here and then we'll need to find a different approach, but I'd like to try to make it work as intended first. This seems like a bug, so I'm going to relabel it as one.

Thanks again for reporting this!

[jmouka]

I should include my Terraform code. The issue could be that the for_each is used with a [for ... in ..].

resource "okta_user" "users" {
  for_each = var.users
  login = each.key
 ...
}
data "okta_group" "dealership" {
  for_each = var.dealers
  name = each.key
}

resource "okta_group_memberships" "mygroup" {
  for_each = var.dealers
  group_id = data.okta_group.dealership[each.key].id
  users = [for username in each.value.users: okta_user.users[username].id ]
}

The input is a JSON of users (var.users), eg:

{
	"jack456" : { "firstName": "firstname"  }
}

and JSON of dealers (var.dealers), each dealer object has an array of usernames:

{
	"dealer123" : { "users": ["john123", "jack456"] }
}

The issue was that one of the var.dealers had a user that was NOT in var.users.