passing empty iterator to dynamic block doesn't destroy previously created resources

[shadjac]

Terraform Version

Terraform v0.12.7

Terraform Configuration Files

**.tfvars**

    secondary_sources = [
        {
        type                         = "BITBUCKET"
        source_identifier            = "common"
        location                     = "https://user@bitbucket.org/repo-name"
        buildspec                    = "config/default/buildspec.yml"
        }

    ]

**main.tf**


  dynamic "secondary_sources" {
    for_each = var.secondary_sources
        content {
            type               = secondary_sources.value.type
            source_identifier  = secondary_sources.value.source_identifier
            buildspec          = secondary_sources.value.buildspec
            location           = secondary_sources.value.location
            }
    }

**variables.tf**

variable "secondary_sources" {
  type = list(object({
    type                 = string
    source_identifier    = string
    location             = string
    buildspec            = string
    
  }))
}

Debug Output

Crash Output

Expected Behavior

Actual Behavior

When

secondary_sources = [
        {
        type                         = "BITBUCKET"
        source_identifier            = "common"
        location                     = "https://user@bitbucket.org/repo-name"
        buildspec                    = "config/default/buildspec.yml"
        }
    ]

terraform plan output

      + secondary_sources {
          + buildspec         = "config/default/buildspec.yml"
          + location          = "https://user@bitbucket.org/repo-name"
          + source_identifier = "common"
          + type              = "BITBUCKET"
        }

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

When secondary_sources array is not empty, it adds the secondary source to code build.
If I want to remove the secondary source, I pass empty array to variable secondary_sources

terraform plan output when secondary_sources=[]

- secondary_sources {
          - buildspec           = "config/default/buildspec.yml" -> null
          - git_clone_depth     = 0 -> null
          - insecure_ssl        = false -> null
          - location            = "https://user@bitbucket.org/repo-name" -> null
          - report_build_status = false -> null
          - source_identifier   = "common" -> null
          - type                = "BITBUCKET" -> null
        }
aws_codebuild_project.code_build_project: Modifying... [id=arn:aws:codebuild:<resource-name>]
aws_codebuild_project.code_build_project: Modifications complete after 1s [id=arn:aws:codebuild:<resource-name>]

Apply complete! Resources: 0 added, 1 changed, 0 destroyed.

But, This is misleading output. I can still see the secondary source on code build.

The state file looks like this -

"secondary_sources": [],

Steps to Reproduce

Please list the full steps required to reproduce the issue, for example:

1. Provide secondary_sources with one element in the list.
2. terraform apply
3. Now, change the value of secondary_sources to [] empty array.
4. terraform apply
5. check whether code build secondary source is removed.

Additional Context

References

• 0.12 "dynamic" blocs fail with empty iterator #21373
• allow empty dynamic blocks with ConfigModeAttr #21549

[mildwonkey]

Hi @shadjac!
Without more information, it's hard to tell if this is a provider resource specific issue or not. Can you please share the full configuration of this resource, and also fill in the rest of the information requested by the template (including your debug log)? Thank you.

[hashibot]

Hello again!

We didn't hear back from you, so I'm going to close this in the hope that a previous response gave you the information you needed. If not, please do feel free to re-open this and leave another comment with the information my human friends requested above. Thanks!

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.