Resource map-typed arguments various crashes

[moio]

Terraform Version

0.8.0 dev, current master (7293630)

Affected Resource(s)

Terraform core, any resource which has an argument of type map (eg. heroku_app's config_vars).

Terraform Configuration Files

provider "heroku" {
    email = "dummy"
    api_key = "dummy"
}

variable "app_config" {
  type = "list"

  default = [
    {
      foo = "bar"
      baz = "bam"
    },
    {
      foo = "bar"
      baz = "bam"
    },
  ]
}
  
resource "heroku_app" "test" {
  name   = "test-app"
  region = "us"

  // Scenario 1
  // this works partially (number of resources is 1, should be 2, see #8867):
  #config_vars = ["${var.app_config}"]

  // this leads to terraform crash (expected type error):
  #config_vars = "${var.app_config}"

  // Scenario 2
  // this works:
  #config_vars = ["${map("foo", "bar")}"]

  // this leads to terraform crash (expected type error):
  #config_vars = "${list(map("foo", "bar"))}"
    
  // Scenario 3
  // this works (type error: should be a map):
  #config_vars = ["${map("foo", "bar")}"]
  #config_vars = ["lalala"]

  // this leads to misleading error (unknown type for string *ast.ListType):
  #config_vars = ["${map("foo", "bar")}"]
  #config_vars = "lalala"
}

Expected Behavior

See comments in scenarios above.

Actual Behavior

See comments in scenarios above.

Steps to Reproduce

1. uncomment one or more lines according to comments above
2. terraform plan

Important Factoids

• I am not sure if this should be reported as 3 separate issues, or if cause is common. Please advise.
• I have another similar bug I cannot presently reproduce with builtin providers, only with terraform-provider-libvirt. I am fairly sure it is a bug in core - should I open an issue for that too?

References

• Outputted map does not contain all expected keys #9549: these issues emerged while testing resolution of this issue

[jbardin]

Hi @moio,

Thanks for the bug report! The crashes should be fixed in master now. As for the type errors, or lack there of, we may have to hold off until after 0.8 where we are planning on reworking the underlying type system which should fix nested map/list encoding ambiguities.

I removed the crash tag, and I'll leave this open pending the interpolation type issues.

[moio]

@jbardin great, thanks so far! I tested in my setup and crashes are indeed gone! 👍

What about scenario 1, where plan is inconsistent on the number of vars? Even in latest terraform I get (emphasis mine):

• heroku_app.test
  all_config_vars.%: ""
  config_vars.#: "2"
  config_vars.0.%: "2"
  config_vars.0.baz: "bam"
  config_vars.0.foo: "bar"
  git_url: ""

Only 1 var is populated despite config_vars.# being 2. This obviously leads to failures during apply, too.

Is there a chance this could be fixed before 0.8, through #8867 or otherwise?

[jbardin]

@moio,

Let me see if I can get the first case working for 0.8. The underlying issue is rather deep, and is going to take a lot of work to solve in it's entirety, but we may be able to add another workaround here.

[jbardin]

These cases are now all working as expected.

The string type error in scenario 3 is now:

config_vars: should be a list

Thanks for the thorough bug report!

[moio]

Thanks for taking care of all of these corner cases @jbardin! I look forward to test them all in my rather complicated setup soon! 😉

[ghost]

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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.