Fix naturaltime overflow for large durations

src/humanize/time.py

@@ -295,12 +295,29 @@ def naturaltime(
 
     now = when or _now()
 
-    date, delta = _date_and_delta(value, now=now)
-    if date is None:
-        return str(value)
-    # determine tense by value only if datetime/timedelta were passed
-    if isinstance(value, (dt.datetime, dt.timedelta)):
+    if isinstance(value, dt.datetime):
+        date, delta = _date_and_delta(value, now=now)
+        if date is None:
+            return str(value)
         future = date > now
+    elif isinstance(value, dt.timedelta):
+        # A timedelta has no calendar date of its own. Avoid constructing one:
+        # valid large durations can extend beyond datetime's supported range.
+        delta = abs(value)
+        future = value < dt.timedelta(0)
+    elif isinstance(value, (int, float)):
+        # Numeric inputs are interpreted as seconds and use `future` as given.
+        # Converting to a timedelta retains the existing rounding and overflow
+        # behavior without requiring an otherwise unused calendar date.
+        try:
+            delta = dt.timedelta(seconds=round(value))
+        except (ValueError, TypeError):
+            return str(value)
+        delta = abs(delta)
+    else:
+        date, delta = _date_and_delta(value, now=now)
+        if date is None:
+            return str(value)
 
     ago = _("%s from now") if future else _("%s ago")
     delta = naturaldelta(delta, months, minimum_unit)

tests/test_time.py

@@ -196,6 +196,11 @@ def test_naturaldelta_too_large_value_raises() -> None:
         (NOW - dt.timedelta(days=365 + 35), "1 year, 1 month ago"),
         (dt.timedelta(days=-10000), "27 years from now"),
         (dt.timedelta(days=365 + 35), "1 year, 1 month ago"),
+        (dt.timedelta(days=4_000_000), "10,959 years ago"),
+        (dt.timedelta(days=-4_000_000), "10,959 years from now"),
+        (dt.timedelta.max, "2,739,726 years ago"),
+        (dt.timedelta.min, "2,739,726 years from now"),
+        (345_600_000_000, "10,959 years ago"),
         (22.5, "22 seconds ago"),
         (23.5, "24 seconds ago"),
         (23.9, "24 seconds ago"),
@@ -211,6 +216,17 @@ def test_naturaltime(
     assert humanize.naturaltime(test_input) == expected
 
 
+@freeze_time(FROZEN_DATE)
+@pytest.mark.parametrize(
+    "future, expected",
+    [(False, "10,959 years ago"), (True, "10,959 years from now")],
+)
+def test_naturaltime_large_numeric_seconds_respects_future(
+    future: bool, expected: str
+) -> None:
+    assert humanize.naturaltime(-345_600_000_000, future=future) == expected
+
+
 @freeze_time(FROZEN_DATE)
 @pytest.mark.parametrize(
     "test_input, expected",