[Bug]: data.aws_vpc_ipam_pools only returns one result

[fsmedw]

Terraform Core Version

1.7.5, 1.9.8

AWS Provider Version

5.77, 5.4, 5.0, 4.67

Affected Resource(s)

data.aws_vpc_ipam_pools

Expected Behavior

Documentation suggest that this resource returns a list of IPAM pools:

ipam_pools - List of IPAM pools and their attributes. See below for details

Actual Behavior

The list of pools only contains a single entry, the first in the list it gets from AWS API, and seems to be a set rather than a list.

Terraform debug output shows that the API returns multiple pools, as does aws cli.

Relevant Error/Panic Output Snippet

❯ terraform plan

data.aws_vpc_ipam_pools.pools: Reading...
data.aws_vpc_ipam_pools.pools: Read complete after 0s [id=eu-west-1]

Changes to Outputs:
  + pools = {
      + filter     = null
      + id         = "eu-west-1"
      + ipam_pools = [
          + {
              + address_family                    = "ipv4"
              + allocation_default_netmask_length = 16
              + allocation_max_netmask_length     = 0
              + allocation_min_netmask_length     = 0
              + allocation_resource_tags          = {}
              + arn                               = "xxx"
              + auto_import                       = true
              + aws_service                       = ""
              + description                       = "xxx"
              + id                                = "xxx"
              + ipam_scope_id                     = "xxx"
              + ipam_scope_type                   = "private"
              + locale                            = "eu-west-1"
              + pool_depth                        = 2
              + publicly_advertisable             = false
              + source_ipam_pool_id               = "xxx"
              + state                             = "create-complete"
              + tags                              = {}
            },
        ]
    }

Terraform Configuration Files

data "aws_vpc_ipam_pools" "pools" {}

output "pools" {
  value = data.aws_vpc_ipam_pools.pools
}

Steps to Reproduce

Have multiple IPAM pools in your account and run terraform plan with the above.

Debug Output

  | <DescribeIpamPoolsResponse xmlns="http://ec2.amazonaws.com/doc/2016-11-15/">
  |     <requestId>e025365f-5520-419a-859d-6d0e8c5fbc89</requestId>
  |     <ipamPoolSet>
  |         <item>
... hiding pool output
  |         </item>
  |         <item>
... hiding pool output
  |         </item>
    | [truncated...]

Panic Output

No response

Important Factoids

In this issue the pools output shows multiple pools: #32106

Docs also say that a filter is required but it works without one. Issue persists even if using a filter.

References

No response

Would you like to implement a fix?

No

[github-actions]

Community Note

Voting for Prioritization

• Please vote on this issue by adding a 👍 reaction to the original post to help the community and maintainers prioritize this request.
• Please see our prioritization guide for information on how we prioritize.
• Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for issue followers and do not help prioritize the request.

Volunteering to Work on This Issue

• If you are interested in working on this issue, please leave a comment.
• If this would be your first contribution, please review the contribution guide.

[plundra]

@fsmedw I've ran with this local patch for a long time; never got around to make PR... Sorry for that, figured it'd be a hassle to fix tests :-)
Hope it helps. I was surprised that it wasn't affecting others since I hit it first time using the IPAM-stuff even.

diff --git a/internal/service/ec2/ipam_pools_data_source.go b/internal/service/ec2/ipam_pools_data_source.go
index 649fb7121f..58d0f1fffb 100644
--- a/internal/service/ec2/ipam_pools_data_source.go
+++ b/internal/service/ec2/ipam_pools_data_source.go
@@ -26,7 +26,7 @@ func dataSourceIPAMPools() *schema.Resource {
 		Schema: map[string]*schema.Schema{
 			names.AttrFilter: customFiltersSchema(),
 			"ipam_pools": {
-				Type:     schema.TypeSet,
+				Type:     schema.TypeList,
 				Computed: true,
 				Elem: &schema.Resource{
 					Schema: map[string]*schema.Schema{