base: Allow nested imports

xbstrap/base.py

@@ -276,6 +276,8 @@ def __init__(
 
         self.source_root = os.path.abspath(self._bootstrap_path)
 
+        self.included_files = list()
+
         root_path = os.path.join(self._bootstrap_path, "bootstrap.yml")
         self._root_yml = self._read_yml(root_path, is_root=True)
 
@@ -423,9 +425,11 @@ def _parse_yml(
         filter_pkgs=None,
         filter_tasks=None,
     ):
+        current_realpath = os.path.realpath(current_path)
+        if current_realpath in self.included_files:
+            raise GenericError(f"Can't import {current_realpath} because it's already imported")
+        self.included_files.append(current_realpath)
         if "imports" in current_yml and isinstance(current_yml["imports"], list):
-            if current_yml is not self._root_yml:
-                raise GenericError("Nested imports are not supported")
             for import_def in current_yml["imports"]:
                 if "from" not in import_def and "file" not in import_def:
                     raise GenericError("Unexpected data in import")