switch from concat to better setunion

infra/terraform/modules/codeowners_file/main.tf

@@ -17,7 +17,7 @@
 locals {
   commit_author = "CFT Bot"
   commit_email  = "[email protected]"
-  owners        = { for value in var.repos_map : value.name => "${join(" ", formatlist("@%s", concat(value.admins, value.maintainers)))} " if concat(value.admins, value.maintainers) > 0 }
+  owners        = { for value in var.repos_map : value.name => "${join(" ", formatlist("@%s", setunion(lookup(value, "admins", []), lookup(value, "maintainers", []))))} " if setunion(lookup(value, "admins", []), lookup(value, "maintainers", [])) > 0 }
   groups        = { for value in var.repos_map : value.name => "${join(" ", formatlist("@${value.org}/%s", value.groups))} " if length(value.groups) > 0 }
   header        = "# NOTE: This file is automatically generated from values at:\n# https://github.com/GoogleCloudPlatform/cloud-foundation-toolkit/blob/master/infra/terraform/test-org/org/locals.tf\n"
   footer_prefix = "# NOTE: GitHub CODEOWNERS locations:\n# https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners#codeowners-and-branch-protection\n"

infra/terraform/test-org/org/github.tf

@@ -16,16 +16,11 @@
 provider "github" {}
 
 locals {
-  owners = distinct(
-    flatten(
-      [for repo, val in local.repos : [for owner in concat(val.admins, val.maintainers) : lower(owner)] if try(val.admins != null || val.maintainers != null, false)]
-    )
+  owners = flatten(
+    [for repo, val in local.repos : [for owner in setunion(lookup(val, "admins", []), lookup(val, "maintainers", [])) : lower(owner)]]
   )
 
-  org_members = setunion(
-    [for login in data.github_organization.tgm.users[*].login : lower(login)],
-    [for login in data.github_organization.gcp.users[*].login : lower(login)]
-  )
+  org_members = [for login in setunion(data.github_organization.tgm.users[*].login, data.github_organization.gcp.users[*].login) : lower(login)]
 
   invalid_owners = setsubtract(local.owners, local.org_members)
 }