feat: allow project root to be customized for stack

main.tf

@@ -137,7 +137,8 @@ locals {
     local._multi_instance_structure ? "${module}-${trimsuffix(file, ".yaml")}" : module =>
     merge(
       {
-        "project_root" = replace(format("%s/%s", var.root_modules_path, module), "../", "")
+        # Use specified project_root, if not, build it using the root_modules_path and module name
+        "project_root" = try(content.project_root, replace(format("%s/%s", var.root_modules_path, module), "../", ""))
         "root_module"  = module,
 
         # If default_tf_workspace_enabled is true, use "default" workspace, otherwise our file name is the workspace name

tests/fixtures/single-instance/root-module-b/stack.yaml

@@ -0,0 +1,7 @@
+stack_settings:
+  administrative: false
+  before_init:
+    - echo 'World'
+  labels:
+    - stack_label
+  project_root: "" # root directory of the project

tests/single-instance.tftest.hcl

@@ -69,6 +69,16 @@ run "test_single_instance_stack_configs_project_root_is_correct" {
   }
 }
 
+run "test_single_instance_stack_configs_custom_project_root_is_used_when_specified" {
+  command = plan
+
+  assert {
+    # root-module-b's stack.yaml specifies `project_root` as "" to indicate root directory of project as source
+    condition = local._root_module_stack_configs["root-module-b"].project_root == ""
+    error_message = "Custom project_root not used: ${jsonencode(local._root_module_stack_configs)}"
+  }
+}
+
 # Test that the administrative label is not added to the stack when the stack is not set to administrative
 run "test_single_instance_administrative_label_is_not_added_to_stack_when_not_administrative" {
   command = plan