Preserve fold in Time.replace

docs/docs/fluent_helpers.md

@@ -65,3 +65,17 @@ converts the time in the appropriate timezone.
 >>> print(dt)
 '2013-03-31T02:30:00+00:00'
 ```
+
+## Replacing time attributes
+
+`Time.replace()` preserves `fold` unless you specify a new value, matching
+`datetime.time.replace()`. This keeps the selected occurrence of an ambiguous
+time when changing other attributes.
+
+```python
+>>> clock = pendulum.Time(1, 30, tzinfo=pendulum.timezone('America/New_York'), fold=1)
+>>> clock.replace(minute=45).fold
+1
+>>> clock.replace(fold=0).fold
+0
+```

src/pendulum/time.py

@@ -269,10 +269,12 @@ def replace(
         second: SupportsIndex | None = None,
         microsecond: SupportsIndex | None = None,
         tzinfo: bool | datetime.tzinfo | Literal[True] | None = True,
-        fold: int = 0,
+        fold: int | None = None,
     ) -> Self:
         if tzinfo is True:
             tzinfo = self.tzinfo
+        if fold is None:
+            fold = self.fold
 
         hour = hour if hour is not None else self.hour
         minute = minute if minute is not None else self.minute
@@ -288,7 +290,7 @@ def replace(
             fold=fold,
         )
         return self.__class__(
-            t.hour, t.minute, t.second, t.microsecond, tzinfo=t.tzinfo
+            t.hour, t.minute, t.second, t.microsecond, tzinfo=t.tzinfo, fold=t.fold
         )
 
     def __getnewargs__(self) -> tuple[Time]:

tests/time/test_fluent_setters.py

@@ -1,5 +1,11 @@
 from __future__ import annotations
 
+import datetime
+
+from zoneinfo import ZoneInfo
+
+import pytest
+
 from pendulum import Time
 from tests.conftest import assert_time
 
@@ -10,3 +16,28 @@ def test_replace():
 
     assert isinstance(t, Time)
     assert_time(t, 1, 2, 3, 654321)
+
+
+@pytest.mark.parametrize("original_fold", [0, 1])
+@pytest.mark.parametrize("replacement_fold", [None, 0, 1])
+def test_replace_fold_matches_native_time(
+    original_fold: int, replacement_fold: int | None
+) -> None:
+    native = datetime.time(
+        1, 30, tzinfo=ZoneInfo("America/New_York"), fold=original_fold
+    )
+    t = Time.instance(native)
+    if replacement_fold is None:
+        expected = native.replace(minute=45)
+        actual = t.replace(minute=45)
+    else:
+        expected = native.replace(minute=45, fold=replacement_fold)
+        actual = t.replace(minute=45, fold=replacement_fold)
+
+    assert isinstance(actual, Time)
+    assert actual.fold == expected.fold
+    assert actual.tzinfo is t.tzinfo
+    day = datetime.date(2026, 11, 1)
+    assert datetime.datetime.combine(day, actual).astimezone(datetime.timezone.utc) == (
+        datetime.datetime.combine(day, expected).astimezone(datetime.timezone.utc)
+    )