fix: add the stdlib fold argument to Time and DateTime

tests/test_items.py

@@ -26,6 +26,7 @@
 from tomlkit.items import Array
 from tomlkit.items import Bool
 from tomlkit.items import Comment
+from tomlkit.items import DateTime
 from tomlkit.items import InlineTable
 from tomlkit.items import Integer
 from tomlkit.items import Item
@@ -35,6 +36,7 @@
 from tomlkit.items import String
 from tomlkit.items import StringType
 from tomlkit.items import Table
+from tomlkit.items import Time
 from tomlkit.items import Trivia
 from tomlkit.items import item
 from tomlkit.parser import Parser
@@ -802,6 +804,46 @@ def test_times_behave_like_times() -> None:
     assert i.as_string() == "13:34:56"
 
 
+def test_times_behave_like_times_fold() -> None:
+    # issue #619: the stdlib `fold` argument is missing from these types.
+    i = item(time(12, 34, 56, fold=1))
+
+    assert i.fold == 1
+    assert i.as_string() == "12:34:56"
+
+    i = i.replace(hour=13)
+    assert i == time(13, 34, 56)
+    assert i.fold == 1
+    assert i.as_string() == "13:34:56"
+
+    j = item(time(12, 34, 56)).replace(fold=1)
+    assert j.fold == 1
+
+    # exact call shape used by pure-python (PyPy) datetime implementations
+    # in `replace()`: type(self)(..., fold=fold)
+    k = Time(12, 34, 56, 0, None, fold=1)
+    assert k.fold == 1
+
+
+def test_datetimes_behave_like_datetimes_fold() -> None:
+    # issue #619: the stdlib `fold` argument is missing from these types.
+    i = item(datetime(2018, 7, 22, 12, 34, 56, fold=1))
+
+    assert i.fold == 1
+
+    i = i.replace(year=2019, fold=1)
+    assert i.fold == 1
+
+    i = i.replace(year=2020)
+    assert i.fold == 1
+
+    j = item(datetime(2018, 7, 22, 12, 34, 56)).replace(fold=1)
+    assert j.fold == 1
+
+    k = DateTime(2018, 7, 22, 12, 34, 56, 0, None, fold=1)
+    assert k.fold == 1
+
+
 def test_strings_behave_like_strs() -> None:
     i = item("foo")
 

tomlkit/items.py

@@ -194,6 +194,7 @@ def item(value: Any, _parent: Item | None = None, _sort_keys: bool = False) -> I
             value.tzinfo,
             Trivia(),
             value.isoformat().replace("+00:00", "Z"),
+            fold=value.fold,
         )
     elif isinstance(value, date):
         return Date(value.year, value.month, value.day, Trivia(), value.isoformat())
@@ -206,6 +207,7 @@ def item(value: Any, _parent: Item | None = None, _sort_keys: bool = False) -> I
             value.tzinfo,
             Trivia(),
             value.isoformat(),
+            fold=value.fold,
         )
     else:
         for encoder in CUSTOM_ENCODERS:
@@ -1040,6 +1042,7 @@ def __new__(
         tzinfo: tzinfo | None,
         trivia: Trivia | None = None,
         raw: str | None = None,
+        fold: int = 0,
         **kwargs: object,
     ) -> DateTime:
         return datetime.__new__(
@@ -1052,6 +1055,7 @@ def __new__(
             second,
             microsecond,
             tzinfo=tzinfo,
+            fold=fold,
         )
 
     def __init__(
@@ -1066,6 +1070,7 @@ def __init__(
         tzinfo: tzinfo | None,
         trivia: Trivia | None = None,
         raw: str | None = None,
+        fold: int = 0,
         **kwargs: object,
     ) -> None:
         super().__init__(trivia or Trivia())
@@ -1164,6 +1169,7 @@ def _new(self, result: datetime) -> DateTime:
             result.tzinfo,
             self._trivia,
             raw,
+            fold=result.fold,
         )
 
     def _getstate(
@@ -1276,8 +1282,9 @@ def __new__(
         tzinfo: tzinfo | None,
         trivia: Trivia | None = None,
         raw: str = "",
+        fold: int = 0,
     ) -> Time:
-        return time.__new__(cls, hour, minute, second, microsecond, tzinfo)
+        return time.__new__(cls, hour, minute, second, microsecond, tzinfo, fold=fold)
 
     def __init__(
         self,
@@ -1288,6 +1295,7 @@ def __init__(
         tzinfo: tzinfo | None,
         trivia: Trivia | None = None,
         raw: str = "",
+        fold: int = 0,
     ) -> None:
         super().__init__(trivia or Trivia())
 
@@ -1322,6 +1330,7 @@ def _new(self, result: time) -> Time:
             result.tzinfo,
             self._trivia,
             raw,
+            fold=result.fold,
         )
 
     def _getstate(