Avoid naming conflicts when importing multiple types with the same name from an ancestor package

betterproto/compile/importing.py

@@ -121,18 +121,20 @@ def reference_ancestor(
     """
     Returns a reference to a python type in a package which is an ancestor to the current package,
     and adds the required import that is aliased (if possible) to avoid name conflicts.
+
+    Adds trailing __ to avoid name mangling (python.org/dev/peps/pep-0008/#id34).
     """
     distance_up = len(current_package) - len(py_package)
     if py_package:
         string_import = py_package[-1]
-        # Add trailing __ to avoid name mangling (python.org/dev/peps/pep-0008/#id34)
         string_alias = f"_{'_' * distance_up}{string_import}__"
         string_from = f"..{'.' * distance_up}"
         imports.add(f"from {string_from} import {string_import} as {string_alias}")
         return f"{string_alias}.{py_type}"
     else:
-        imports.add(f"from .{'.' * distance_up} import {py_type}")
-        return py_type
+        string_alias = f"{'_' * distance_up}{py_type}__"
+        imports.add(f"from .{'.' * distance_up} import {py_type} as {string_alias}")
+        return string_alias
 
 
 def reference_cousin(

betterproto/tests/test_get_ref_type.py

@@ -214,8 +214,8 @@ def test_reference_root_package_from_child():
         package="package.child", imports=imports, source_type="Message"
     )
 
-    assert imports == {"from ... import Message"}
-    assert name == "Message"
+    assert imports == {"from ... import Message as __Message__"}
+    assert name == "__Message__"
 
 
 def test_reference_root_package_from_deeply_nested_child():
@@ -224,8 +224,8 @@ def test_reference_root_package_from_deeply_nested_child():
         package="package.deeply.nested.child", imports=imports, source_type="Message"
     )
 
-    assert imports == {"from ..... import Message"}
-    assert name == "Message"
+    assert imports == {"from ..... import Message as ____Message__"}
+    assert name == "____Message__"
 
 
 def test_reference_unrelated_package():