aws_cloudformation_stack update doesn't send parameters if paremeters are not modified

[rmazlumyan]

When performing an update to a cloudformation stack, parameters are only sent if they are modified. This results in the following error:

* aws_cloudformation_stack.vpc: ValidationError: Parameters: [ZoneName] must have values
    status code: 400, request id: 2794fb5d-c6ea-11e5-bb25-f7d7bfdc24bc

The following stack is created on initial run:

resource "aws_cloudformation_stack" "vpc" {
    name = "dev-vpc"
    template_url = "https://s3.amazonaws.com/${var.template_bucket}/CreateVPC.json"
    on_failure = "ROLLBACK"
    parameters {
        CreateNewZone = "false"
        VPCName = "dev-us-west-2"
        ZoneName = "mydomain.com"
    }
}

After updating the template_url

resource "aws_cloudformation_stack" "vpc" {
    name = "dev-vpc"
    template_url = "https://s3.amazonaws.com/${var.template_bucket}/CreateVPC.json?versionId=hwUzxuE55wT2qLtwDyK3a7GBcHYzEvaQ"
    on_failure = "ROLLBACK"
    parameters {
        CreateNewZone = "false"
        VPCName = "dev-us-west-2"
        ZoneName = "mydomain.com"
    }
}

and running apply the following is seen in the error log:

2016/01/29 17:01:12 [DEBUG] apply: aws_cloudformation_stack.vpc: executing Apply
2016/01/29 17:01:12 [DEBUG] terraform-provider-aws: 2016/01/29 17:01:12 [DEBUG] Updating CloudFormation stack: {
2016/01/29 17:01:12 [DEBUG] terraform-provider-aws:   StackName: "dev-vpc",
2016/01/29 17:01:12 [DEBUG] terraform-provider-aws:   TemplateURL: "https://s3.amazonaws.com/mycloudformation/CreateVPC.json?versionId=hwUzxuE55wT2qLtwDyK3a7GBcHYzEvaQ"
2016/01/29 17:01:12 [DEBUG] terraform-provider-aws: }
2016/01/29 17:01:13 [DEBUG] root: eval: *terraform.EvalWriteState
2016/01/29 17:01:13 [DEBUG] root: eval: *terraform.EvalApplyProvisioners
2016/01/29 17:01:13 [DEBUG] root: eval: *terraform.EvalIf
2016/01/29 17:01:13 [DEBUG] root: eval: *terraform.EvalWriteDiff
2016/01/29 17:01:13 [DEBUG] root: eval: *terraform.EvalIf
2016/01/29 17:01:13 [DEBUG] root: eval: *terraform.EvalWriteState
2016/01/29 17:01:13 [DEBUG] root: eval: *terraform.EvalApplyPost
2016/01/29 17:01:13 [ERROR] root: eval: *terraform.EvalApplyPost, err: 1 error(s) occurred:

* aws_cloudformation_stack.vpc: ValidationError: Parameters: [ZoneName] must have values
        status code: 400, request id: f52d821f-c6ec-11e5-94bf-29cecbcddbfb
2016/01/29 17:01:13 [ERROR] root: eval: *terraform.EvalSequence, err: 1 error(s) occurred:

[radeksimko]

Hi @rmazlumyan ,
thanks for the report.

This was just fixed with @olegch's help and merged in #5603 which will be part of the next release.

[ghost]

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