ok, seems that import_dir is a bit saner

my/core/common.py

@@ -9,6 +9,7 @@ import warnings
 # some helper functions
 PathIsh = Union[Path, str]
 
+# TODO only used in tests? not sure if useful at all.
 # TODO port annotations to kython?..
 def import_file(p: PathIsh, name: Optional[str]=None) -> types.ModuleType:
     p = Path(p)
@@ -33,6 +34,11 @@ def import_from(path: PathIsh, name: str) -> types.ModuleType:
         sys.path.remove(path)
 
 
+def import_dir(path: PathIsh) -> types.ModuleType:
+    p = Path(path)
+    return import_from(p.parent, p.name)
+
+
 T = TypeVar('T')
 K = TypeVar('K')
 V = TypeVar('V')

my/demo.py

@@ -24,8 +24,8 @@ class demo(user_config):
     def external_module(self):
         rpath = self.external
         if rpath is not None:
-            from .cfg import set_repo
-            set_repo('external', rpath)
+            from .core.common import import_dir
+            return import_dir(rpath)
 
         import my.config.repos.external as m # type: ignore
         return m

tests/demo.py

@@ -104,7 +104,14 @@ def prepare(tmp_path: Path):
 ''')
     ext = tmp_path / 'external'
     ext.mkdir()
-    (ext / '__init__.py').write_text('identity = lambda x: x')
+    (ext / '__init__.py').write_text('''
+def identity(x):
+    from .submodule import hello
+    hello(x)
+    return x
+
+''')
+    (ext / 'submodule.py').write_text('hello = lambda x: print("hello " + str(x))')
     yield
     ex = 'my.config.repos.external'
     if ex in sys.modules: