fix: treat set/frozenset as JSON-storable types in types_for_column_types

sqlite_utils/utils.py

@@ -150,9 +150,9 @@ def types_for_column_types(
             t = str
         elif len(types) == 1:
             t = next(iter(types))
-            # But if it's a subclass of list / tuple / dict, use str
+            # But if it's a subclass of list / tuple / dict / set, use str
             # instead as we will be storing it as JSON in the table
-            for superclass in (list, tuple, dict):
+            for superclass in (list, tuple, dict, set, frozenset):
                 if issubclass(t, superclass):
                     t = str
         elif {int, bool}.issuperset(types):

tests/test_utils.py

@@ -102,3 +102,12 @@ def test_flatten(input, expected):
 )
 def test_dedupe_keys(input, expected):
     assert utils.dedupe_keys(input) == expected
+
+
+def test_types_for_column_types_set_maps_to_str():
+    """set and frozenset should be mapped to str for JSON storage, like list/tuple/dict"""
+    result = utils.types_for_column_types({"tags": {set}})
+    assert result["tags"] is str
+
+    result = utils.types_for_column_types({"tags": {frozenset}})
+    assert result["tags"] is str