gh-152849: Fix OverflowError message for out-of-range timestamps in the time module (#152850)

Co-authored-by: Stan Ulbrych <stan@python.org>

Author: tonghuaroot

Lib/test/test_time.py

@@ -1013,6 +1013,17 @@ def test_FromSecondsObject(self):
             with self.assertRaises(ValueError):
                 _PyTime_FromSecondsObject(float('nan'), time_rnd)
 
+    def test_FromSecondsObject_float_overflow_message(self):
+        # Float path must report a PyTime_t overflow, like the integer path.
+        from _testinternalcapi import _PyTime_FromSecondsObject
+        for value in (PyTime_MAX, PyTime_MIN):
+            for time_rnd, _ in ROUNDING_MODES:
+                with self.subTest(value=value, time_rnd=time_rnd):
+                    with self.assertRaisesRegex(
+                            OverflowError,
+                            "timestamp out of range for C PyTime_t"):
+                        _PyTime_FromSecondsObject(value, time_rnd)
+
     def test_AsSecondsDouble(self):
         from _testcapi import PyTime_AsSecondsDouble
 

Misc/NEWS.d/next/Library/2026-07-02-13-30-00.gh-issue-152849.K9dRvP.rst

@@ -0,0 +1,2 @@
+Out-of-range float and integer timestamps now raise :exc:`OverflowError`
+with the same message. Patch by tonghuaroot.

Python/pytime.c

@@ -107,7 +107,7 @@ static void
 pytime_overflow(void)
 {
     PyErr_SetString(PyExc_OverflowError,
-                    "timestamp too large to convert to C PyTime_t");
+                    "timestamp out of range for C PyTime_t");
 }
 
 
@@ -636,7 +636,7 @@ pytime_from_double(PyTime_t *tp, double value, _PyTime_round_t round,
 
     /* See comments in pytime_double_to_denominator */
     if (!((double)PyTime_MIN <= d && d < -(double)PyTime_MIN)) {
-        pytime_time_t_overflow();
+        pytime_overflow();
         *tp = 0;
         return -1;
     }