TST: read_csv with custom date parser and na_filter=True results in ValueError

pandas/tests/io/parser/test_parse_dates.py

@@ -34,6 +34,43 @@
     date_strategy = st.datetimes()
 
 
+def test_read_csv_with_custom_date_parser(all_parsers):
+    # GH36111
+    def __custom_date_parser(time):
+        time = time.astype(np.float)
+        time = time.astype(np.int)  # convert float seconds to int type
+        return pd.to_timedelta(time, unit="s")
+
+    testdata = StringIO(
+        """time e n h
+        41047.00 -98573.7297 871458.0640 389.0089
+        41048.00 -98573.7299 871458.0640 389.0089
+        41049.00 -98573.7300 871458.0642 389.0088
+        41050.00 -98573.7299 871458.0643 389.0088
+        41051.00 -98573.7302 871458.0640 389.0086
+        """
+    )
+    result = all_parsers.read_csv(
+        testdata,
+        delim_whitespace=True,
+        parse_dates=True,
+        date_parser=__custom_date_parser,
+        index_col="time",
+    )
+    time = [41047, 41048, 41049, 41050, 41051]
+    time = pd.TimedeltaIndex([pd.to_timedelta(i, unit="s") for i in time], name="time")
+    expected = DataFrame(
+        {
+            "e": [-98573.7297, -98573.7299, -98573.7300, -98573.7299, -98573.7302],
+            "n": [871458.0640, 871458.0640, 871458.0642, 871458.0643, 871458.0640],
+            "h": [389.0089, 389.0089, 389.0088, 389.0088, 389.0086],
+        },
+        index=time,
+    )
+
+    tm.assert_frame_equal(result, expected)
+
+
 def test_separator_date_conflict(all_parsers):
     # Regression test for gh-4678
     #