commit 0a834c18cdafa5447d4436878e64aa7a4e4dc817
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Tue Feb 12 04:11:48 2019 -0800
committer Eric V. Smith <ericvsmith@users.noreply.github.com> Tue Feb 12 07:11:48 2019 -0500
tree 13db9a2aff9363045aa70b2f9ccdc2d655cfc675
parent 58f05ce059cc5207320fef27a9fbc0ffdc2b1d1a

bpo-35960: Fix dataclasses.field throwing away empty metadata.  (GH-11815) (GH-11826)

(cherry picked from commit b01786c8812c4cc24dd561b5941025bdd6f444c0)

Co-authored-by: Christopher Hunt <chrahunt@gmail.com>

Lib/dataclasses.py

diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
index 71d9896..325b822 100644
--- a/Lib/dataclasses.py
+++ b/Lib/dataclasses.py
@@ -241,7 +241,7 @@
         self.hash = hash
         self.compare = compare
         self.metadata = (_EMPTY_METADATA
-                         if metadata is None or len(metadata) == 0 else
+                         if metadata is None else
                          types.MappingProxyType(metadata))
         self._field_type = None