Fix error in orjson engine when a dict has a non-string value as a key (#3351)

* Convert dict keys to strings during cleaning for orjson encoder
* CHANGELOG.md entry

Author: jonmmease

CHANGELOG.md

@@ -2,6 +2,11 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [5.2.2] - ???
+
+### Fixed
+  - Fixed error when using the orjson engine with non-string keys  
+
 ## [5.2.1] - 2021-08-13
 
 ### Updated

packages/python/plotly/plotly/io/_json.py

@@ -462,7 +462,7 @@ def clean_to_json_compatible(obj, **kwargs):
         return obj
 
     if isinstance(obj, dict):
-        return {k: clean_to_json_compatible(v, **kwargs) for k, v in obj.items()}
+        return {str(k): clean_to_json_compatible(v, **kwargs) for k, v in obj.items()}
     elif isinstance(obj, (list, tuple)):
         if obj:
             # Must process list recursively even though it may be slow

packages/python/plotly/plotly/tests/test_io/test_to_from_plotly_json.py

@@ -209,3 +209,9 @@ def test_object_array(engine, pretty):
     fig = px.scatter(px.data.tips(), x="total_bill", y="tip", custom_data=["sex"])
     result = fig.to_plotly_json()
     check_roundtrip(result, engine=engine, pretty=pretty)
+
+
+def test_nonstring_key(engine, pretty):
+    value = build_test_dict({0: 1})
+    result = pio.to_json_plotly(value, engine=engine)
+    check_roundtrip(result, engine=engine, pretty=pretty)