Review (jreback)

doc/source/whatsnew/v0.24.0.txt

@@ -210,6 +210,7 @@ Backwards incompatible API changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 - A newly constructed empty :class:`DataFrame` with integer as the ``dtype`` will now only be cast to ``float64`` if ``index`` is specified (:issue:`22858`)
+- :meth:`Series.str.cat` will now raise if `others` is a `set` (:issue:`23009`)
 
 .. _whatsnew_0240.api_breaking.deps:
 
@@ -976,7 +977,7 @@ Numeric
 Strings
 ^^^^^^^
 
-- Bug in :meth:`Series.str.cat` which falsely did not raise if `others` was a `set` (:issue:`23009`)
+-
 -
 -
 

pandas/tests/test_strings.py

@@ -302,10 +302,12 @@ def test_str_cat_mixed_inputs(self, box):
             s.str.cat([u, [u, d]])
 
         # forbidden input type: set
+        # GH 23009
         with tm.assert_raises_regex(TypeError, rgx):
             s.str.cat(set(u))
 
         # forbidden input type: set in list
+        # GH 23009
         with tm.assert_raises_regex(TypeError, rgx):
             s.str.cat([u, set(u)])