resource/aws_ecs_service: allow in-place removal of managed EBS volume_configuration

[mealingr]

Rollback Plan

If a change needs to be reverted, we will publish an updated version of the library.

Changes to Security Controls

None.

Description

Removing a managed EBS volume from an existing aws_ecs_service (deleting the volume_configuration block) currently fails on apply:

InvalidParameterException: Volume configuration provided but no matching configuredAtLaunch volume found in task definition

On update, the emptied volume_configuration was passed straight to expandServiceVolumeConfigurations, which returns nil for an empty list. UpdateService treats a nil volumeConfigurations as "no change" and keeps the existing volume configuration, which then conflicts with the new task-definition revision whose volume is no longer configuredAtLaunch.

AWS documents removal as passing an empty volumeConfigurations array together with a task definition whose volume has configuredAtLaunch = false (Configure a service to no longer utilize Amazon EBS volumes). This seeds an empty slice before conditionally expanding, mirroring how placement_constraints already handles removal in the same function. Enable/resize are unchanged.

References

https://docs.aws.amazon.com/AmazonECS/latest/developerguide/configure-ebs-volume.html

Output from Acceptance Testing

% make testacc TESTS=TestAccECSService_VolumeConfiguration_remove PKG=ecs
TF_ACC=1 go test ./internal/service/ecs/... -run='TestAccECSService_VolumeConfiguration_remove' -timeout 360m
=== RUN   TestAccECSService_VolumeConfiguration_remove
--- PASS: TestAccECSService_VolumeConfiguration_remove (90.81s)
PASS
ok  	github.com/hashicorp/terraform-provider-aws/internal/service/ecs	90.958s

[github-actions]

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[github-actions]

✅ Thank you for correcting the previously detected issues! The maintainers appreciate your efforts to make the review process as smooth as possible.