fix: work around to_json pandas deprecation

freqtrade/misc.py

@@ -214,6 +214,12 @@ def dataframe_to_json(dataframe: pd.DataFrame) -> str:
     :param dataframe: A pandas DataFrame
     :returns: A JSON string of the pandas DataFrame
     """
+    date_columns = dataframe.select_dtypes(include=["datetime", "datetime64", "datetimetz"])
+    # Explicit conversion to ms
+    # This used to be part of to_json, but was deprecated in pandas 3
+    for date_column in date_columns:
+        dataframe[date_column] = date_columns[date_column].dt.as_unit("ms").astype("int64")
+
     return dataframe.to_json(orient="split")
 
 

tests/test_misc.py

@@ -230,7 +230,7 @@ def test_deep_merge_dicts():
 def test_dataframe_json(ohlcv_history):
     from pandas.testing import assert_frame_equal
 
-    json = dataframe_to_json(ohlcv_history)
+    json = dataframe_to_json(ohlcv_history.copy())
     dataframe = json_to_dataframe(json)
 
     assert list(ohlcv_history.columns) == list(dataframe.columns)
@@ -238,6 +238,6 @@ def test_dataframe_json(ohlcv_history):
 
     assert_frame_equal(ohlcv_history, dataframe)
     ohlcv_history.at[1, "date"] = pd.NaT
-    json = dataframe_to_json(ohlcv_history)
+    json = dataframe_to_json(ohlcv_history.copy())
 
     dataframe = json_to_dataframe(json)