[gitlab_release] "released_at" data format inconsistency

Bug Report

Creating a release with "gitlab_release" that contains set date of the release ("released_at") inconsistently parses the date

Relevant Terraform Configuration

resource "gitlab_release" "test" {
  project     = "<PROJECT_ID>"
  tag_name    = "0.1.0"
  name        = "Legacy Release"
  released_at = "2025-06-15"
  ref         = "<COMMIT_REF>"
}

resource "gitlab_release" "test2" {
  project     = "<PROJECT_ID>"
  tag_name    = "0.1.0"
  name        = "Legacy Release"
  released_at = "2025-06-15T00:00:00Z"
  ref         = "<COMMIT_REF>"
}

Relevant Terraform Command

terraform apply

Relevant Log Output

These are the debug logs of the `terraform` command output:

$ tofu apply -target gitlab_release.test                                                                                                                                                                                                      

OpenTofu will perform the following actions:

  # gitlab_release.test will be created
  + resource "gitlab_release" "test" {
      + assets           = (known after apply)
      + author           = (known after apply)
      + commit           = (known after apply)
      + commit_path      = (known after apply)
      + created_at       = (known after apply)
      + description      = (known after apply)
      + description_html = (known after apply)
      + id               = (known after apply)
      + links            = (known after apply)
      + name             = "Legacy Release"
      + project          = "xxx"
      + ref              = "xxx"
      + released_at      = "2025-06-15"
      + tag_name         = "0.1.0"
      + tag_path         = (known after apply)
      + upcoming_release = (known after apply)
    }

Plan: 1 to add, 0 to change, 0 to destroy.

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gitlab_release.test: Creating...
╷
│ Error: Provider produced inconsistent result after apply
│ 
│ When applying changes to gitlab_release.test, provider "provider[\"registry.opentofu.org/gitlabhq/gitlab\"]" produced an unexpected new value: .released_at: was cty.StringVal("2025-06-15"), but now cty.StringVal("2025-06-15T00:00:00Z").
│ 
│ This is a bug in the provider, which should be reported in the provider's own issue tracker.


##

tofu apply -target gitlab_release.test2

OpenTofu will perform the following actions:

  # gitlab_release.test will be created
  + resource "gitlab_release" "test2" {
      + assets           = (known after apply)
      + author           = (known after apply)
      + commit           = (known after apply)
      + commit_path      = (known after apply)
      + created_at       = (known after apply)
      + description      = (known after apply)
      + description_html = (known after apply)
      + id               = (known after apply)
      + links            = (known after apply)
      + name             = "Legacy Release"
      + project          = "xxx"
      + ref              = "xxx"
      + released_at      = "2025-06-15T00:00:00Z"
      + tag_name         = "0.1.0"
      + tag_path         = (known after apply)
      + upcoming_release = (known after apply)
    }

Plan: 1 to add, 0 to change, 0 to destroy.
╷
│ Error: Error parsing released at date
│ 
│   with gitlab_release.test,
│   on release.tf line 110, in resource "gitlab_release" "test2":
│  110: resource "gitlab_release" "test2" {
│ 
│ Could not parse released at date "2025-06-15T00:00:00Z": parsing time "2025-06-15T00:00:00Z": extra text: "T00:00:00Z"

Additional Details

• tofu -version OpenTofu v1.11.5 on linux_amd64 provider registry.opentofu.org/gitlabhq/gitlab v18.9.0
• GitLab Instance Version: Current at Gitlab.com at the time of issue submission
• License Tier: Free