1 files changed, 13 insertions, 1 deletions
diff --git a/Lib/importlib/_bootstrap.py b/Lib/importlib/_bootstrap.py
index 6f62bb3..f0a4e1c 100644
--- a/Lib/importlib/_bootstrap.py
+++ b/Lib/importlib/_bootstrap.py
@@ -1033,7 +1033,19 @@ def _calc___package__(globals):
 
     """
     package = globals.get('__package__')
-    if package is None:
+    spec = globals.get('__spec__')
+    if package is not None:
+        if spec is not None and package != spec.parent:
+            _warnings.warn("__package__ != __spec__.parent "
+                           f"({package!r} != {spec.parent!r})",
+                           ImportWarning, stacklevel=3)
+        return package
+    elif spec is not None:
+        return spec.parent
+    else:
+        _warnings.warn("can't resolve package from __spec__ or __package__, "
+                       "falling back on __name__ and __path__",
+                       ImportWarning, stacklevel=3)
         package = globals['__name__']
         if '__path__' not in globals:
             package = package.rpartition('.')[0]