Raise TypeError only if key DataFrame is not empty

Author: rekcahpassyla

pandas/core/frame.py

@@ -2151,7 +2151,7 @@ def _setitem_array(self, key, value):
     def _setitem_frame(self, key, value):
         # support boolean setting with DataFrame input, e.g.
         # df[df > df2] = 0
-        if key.values.dtype != np.bool_:
+        if key.values.size and key.values.dtype != np.bool_:
             raise TypeError('Must pass DataFrame with boolean values only')
 
         self._check_inplace_setting(value)