From 825642859862b8e836e716c7006d038e661dcb92 Mon Sep 17 00:00:00 2001 From: Ayomide906 Date: Fri, 19 Sep 2025 13:54:45 +0100 Subject: [PATCH] Add failing test for pyarrow datetime merge issue --- pandas/tests/reshape/merge/test_merge.py | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/pandas/tests/reshape/merge/test_merge.py b/pandas/tests/reshape/merge/test_merge.py index d3bef4c863b28..445fabb9a2f1b 100644 --- a/pandas/tests/reshape/merge/test_merge.py +++ b/pandas/tests/reshape/merge/test_merge.py @@ -3097,3 +3097,15 @@ def test_merge_categorical_key_recursion(): right.astype("float64"), on="key", how="outer" ) tm.assert_frame_equal(result, expected) +def test_merge_pyarrow_datetime(): + import pandas as pd + + t = pd.date_range("2025-07-06", periods=3, freq="h") + df1 = pd.DataFrame({"time": t, "val1": [1, 2, 3]}) + df2 = pd.DataFrame({"time": t.repeat(2), "val2": [10, 20, 30, 40, 50, 60]}) + + df1 = df1.convert_dtypes(dtype_backend="pyarrow") + df2 = df2.convert_dtypes(dtype_backend="pyarrow") + + pd.merge(df1, df2, on="time", how="left") # This currently raises ValueError +