/terraform-provider-heroku/heroku.resourceHerokuFormationRead: invalid memory address or nil pointer dereference

[cwallsfdc]

Seeing the following during "heroku_formation.app: Refreshing state..."...

panic: runtime error: invalid memory address or nil pointer dereference
2019-07-01T21:06:46.755-0600 [DEBUG] plugin.terraform-provider-heroku_v2.0.1_x4: [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xd8687c]
2019-07-01T21:06:46.755-0600 [DEBUG] plugin.terraform-provider-heroku_v2.0.1_x4: 
2019-07-01T21:06:46.755-0600 [DEBUG] plugin.terraform-provider-heroku_v2.0.1_x4: goroutine 113 [running]:
2019-07-01T21:06:46.755-0600 [DEBUG] plugin.terraform-provider-heroku_v2.0.1_x4: github.com/terraform-providers/terraform-provider-heroku/heroku.resourceHerokuFormationRead(0xc0002e9d50, 0xf0dd80, 0xc0001a5bc0, 0xc0002e9d50, 0x0)

Terraform Version

Terraform v0.12.3
+ provider.heroku v2.0.1

Heroku Provider Version

See above.

Affected Resource(s)

• resource "heroku_formation"
• resource "heroku_build"

Terraform Configuration Files

Available upon request.

Debug Output

https://gist.github.com/cwallsfdc/c6fdc8c726919a700a81e6fc27e0a89d

Panic Output

https://gist.github.com/cwallsfdc/59f17c57f89cf7928f7e8bec84707938

Expected Behavior

A generated plan that builds and starts app.

Actual Behavior

panic: runtime error: invalid memory address or nil pointer dereference
2019-07-01T21:06:46.755-0600 [DEBUG] plugin.terraform-provider-heroku_v2.0.1_x4: [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xd8687c]
2019-07-01T21:06:46.755-0600 [DEBUG] plugin.terraform-provider-heroku_v2.0.1_x4: 
2019-07-01T21:06:46.755-0600 [DEBUG] plugin.terraform-provider-heroku_v2.0.1_x4: goroutine 113 [running]:
2019-07-01T21:06:46.755-0600 [DEBUG] plugin.terraform-provider-heroku_v2.0.1_x4: github.com/terraform-providers/terraform-provider-heroku/heroku.resourceHerokuFormationRead(0xc0002e9d50, 0xf0dd80, 0xc0001a5bc0, 0xc0002e9d50, 0x0)

Steps to Reproduce

See "Important Factoids".

Important Factoids

Changed app.tf from heroku_slug to heroku_build then ran terraform plan.

From:

# Create a slug for the app with a local slug archive file
resource "heroku_slug" "app" {
  app                            = "${heroku_app.app.id}"
  buildpack_provided_description = "Java"
  file_path                      = "${local.slug_filepath}"
  stack                          = "${local.stack}"

  commit = "${var.commit}"

  process_types = {
    web = "${local.web}"
  }
}

# Deploy a release to the app with the slug
resource "heroku_app_release" "app" {
  app     = "${heroku_app.app.id}"
  slug_id = "${heroku_slug.app.id}"
  depends_on = ["heroku_slug.app"]
}

# Launch the app's web process by scaling-up
resource "heroku_formation" "app" {
  app        = "${heroku_app.app.id}"
  type       = "web"
  quantity   = "${local.dyno_count}"
  size       = "${local.dyno_size}"
  depends_on = ["heroku_app_release.app"]
}

To:

resource "heroku_build" "app" {
    app = "${heroku_app.app.id}"

    buildpacks = "${local.buildpacks}"

    source = {
        path = "${local.slug_filepath}"
    }
}

# Launch the app's web process by scaling-up
resource "heroku_formation" "app" {
    app        = "${heroku_app.app.id}"
    type       = "web"
    quantity   = "${local.dyno_count}"
    size       = "${local.dyno_size}"
    depends_on = ["heroku_build.app"]
}

[mars]

This is definitely a bug 🐞buuuuut if you try removing the existing formation from state and then re-apply, does it get past this?

terraform state rm heroku_formation.app
terraform plan

Formations are kind of weird ephemeral things, and using Terraform to try to migrate between build/release methods like that is undefined behavior.

[cwallsfdc]

does it get past this?

Indeed it does. Thank you.