Add fold kwarg for arrow.get

arrow/api.py

@@ -25,6 +25,7 @@ def get(
     *,
     locale: str = DEFAULT_LOCALE,
     tzinfo: Optional[TZ_EXPR] = None,
+    fold: Optional[int] = 0,
     normalize_whitespace: bool = False,
 ) -> Arrow:
     ...  # pragma: no cover
@@ -35,6 +36,7 @@ def get(
     *args: int,
     locale: str = DEFAULT_LOCALE,
     tzinfo: Optional[TZ_EXPR] = None,
+    fold: Optional[int] = 0,
     normalize_whitespace: bool = False,
 ) -> Arrow:
     ...  # pragma: no cover
@@ -56,6 +58,7 @@ def get(
     *,
     locale: str = DEFAULT_LOCALE,
     tzinfo: Optional[TZ_EXPR] = None,
+    fold: Optional[int] = 0,
     normalize_whitespace: bool = False,
 ) -> Arrow:
     ...  # pragma: no cover
@@ -68,6 +71,7 @@ def get(
     *,
     locale: str = DEFAULT_LOCALE,
     tzinfo: Optional[TZ_EXPR] = None,
+    fold: Optional[int] = 0,
     normalize_whitespace: bool = False,
 ) -> Arrow:
     ...  # pragma: no cover
@@ -80,6 +84,7 @@ def get(
     *,
     locale: str = DEFAULT_LOCALE,
     tzinfo: Optional[TZ_EXPR] = None,
+    fold: Optional[int] = 0,
     normalize_whitespace: bool = False,
 ) -> Arrow:
     ...  # pragma: no cover

arrow/arrow.py

@@ -159,7 +159,8 @@ def __init__(
         second: int = 0,
         microsecond: int = 0,
         tzinfo: Optional[TZ_EXPR] = None,
-        **kwargs: Any,
+        *,
+        fold: int = 0,
     ) -> None:
         if tzinfo is None:
             tzinfo = dateutil_tz.tzutc()
@@ -174,8 +175,6 @@ def __init__(
         elif isinstance(tzinfo, str):
             tzinfo = parser.TzinfoParser.parse(tzinfo)
 
-        fold = kwargs.get("fold", 0)
-
         self._datetime = dt_datetime(
             year, month, day, hour, minute, second, microsecond, tzinfo, fold=fold
         )
@@ -210,7 +209,7 @@ def now(cls, tzinfo: Optional[dt_tzinfo] = None) -> "Arrow":
             dt.second,
             dt.microsecond,
             dt.tzinfo,
-            fold=getattr(dt, "fold", 0),
+            fold=dt.fold,
         )
 
     @classmethod
@@ -236,7 +235,7 @@ def utcnow(cls) -> "Arrow":
             dt.second,
             dt.microsecond,
             dt.tzinfo,
-            fold=getattr(dt, "fold", 0),
+            fold=dt.fold,
         )
 
     @classmethod
@@ -273,7 +272,7 @@ def fromtimestamp(
             dt.second,
             dt.microsecond,
             dt.tzinfo,
-            fold=getattr(dt, "fold", 0),
+            fold=dt.fold,
         )
 
     @classmethod
@@ -299,11 +298,16 @@ def utcfromtimestamp(cls, timestamp: Union[int, float, str]) -> "Arrow":
             dt.second,
             dt.microsecond,
             dateutil_tz.tzutc(),
-            fold=getattr(dt, "fold", 0),
+            fold=dt.fold,
         )
 
     @classmethod
-    def fromdatetime(cls, dt: dt_datetime, tzinfo: Optional[TZ_EXPR] = None) -> "Arrow":
+    def fromdatetime(
+        cls,
+        dt: dt_datetime,
+        tzinfo: Optional[TZ_EXPR] = None,
+        fold: Optional[int] = None,
+    ) -> "Arrow":
         """Constructs an :class:`Arrow <arrow.arrow.Arrow>` object from a ``datetime`` and
         optional replacement timezone.
 
@@ -326,6 +330,9 @@ def fromdatetime(cls, dt: dt_datetime, tzinfo: Optional[TZ_EXPR] = None) -> "Arr
             else:
                 tzinfo = dt.tzinfo
 
+        if fold is None:
+            fold = dt.fold
+
         return cls(
             dt.year,
             dt.month,
@@ -335,7 +342,7 @@ def fromdatetime(cls, dt: dt_datetime, tzinfo: Optional[TZ_EXPR] = None) -> "Arr
             dt.second,
             dt.microsecond,
             tzinfo,
-            fold=getattr(dt, "fold", 0),
+            fold=fold,
         )
 
     @classmethod
@@ -355,10 +362,14 @@ def fromdate(cls, date: date, tzinfo: Optional[TZ_EXPR] = None) -> "Arrow":
 
     @classmethod
     def strptime(
-        cls, date_str: str, fmt: str, tzinfo: Optional[TZ_EXPR] = None
+        cls,
+        date_str: str,
+        fmt: str,
+        tzinfo: Optional[TZ_EXPR] = None,
+        fold: Optional[int] = None,
     ) -> "Arrow":
         """Constructs an :class:`Arrow <arrow.arrow.Arrow>` object from a date string and format,
-        in the style of ``datetime.strptime``.  Optionally replaces the parsed timezone.
+        in the style of ``datetime.strptime``.  Optionally replaces the parsed timezone and fold.
 
         :param date_str: the date string.
         :param fmt: the format string using datetime format codes.
@@ -376,6 +387,9 @@ def strptime(
         if tzinfo is None:
             tzinfo = dt.tzinfo
 
+        if fold is None:
+            fold = dt.fold
+
         return cls(
             dt.year,
             dt.month,
@@ -385,7 +399,7 @@ def strptime(
             dt.second,
             dt.microsecond,
             tzinfo,
-            fold=getattr(dt, "fold", 0),
+            fold=fold,
         )
 
     @classmethod
@@ -413,7 +427,7 @@ def fromordinal(cls, ordinal: int) -> "Arrow":
             dt.second,
             dt.microsecond,
             dt.tzinfo,
-            fold=getattr(dt, "fold", 0),
+            fold=dt.fold,
         )
 
     # factories: ranges and spans
@@ -1087,7 +1101,7 @@ def to(self, tz: TZ_EXPR) -> "Arrow":
             dt.second,
             dt.microsecond,
             dt.tzinfo,
-            fold=getattr(dt, "fold", 0),
+            fold=dt.fold,
         )
 
     # string output and formatting

arrow/factory.py

@@ -40,6 +40,7 @@ def get(
         *,
         locale: str = DEFAULT_LOCALE,
         tzinfo: Optional[TZ_EXPR] = None,
+        fold: Optional[int] = None,
         normalize_whitespace: bool = False,
     ) -> Arrow:
         ...  # pragma: no cover
@@ -61,6 +62,7 @@ def get(
         *,
         locale: str = DEFAULT_LOCALE,
         tzinfo: Optional[TZ_EXPR] = None,
+        fold: Optional[int] = None,
         normalize_whitespace: bool = False,
     ) -> Arrow:
         ...  # pragma: no cover
@@ -73,6 +75,7 @@ def get(
         *,
         locale: str = DEFAULT_LOCALE,
         tzinfo: Optional[TZ_EXPR] = None,
+        fold: Optional[int] = None,
         normalize_whitespace: bool = False,
     ) -> Arrow:
         ...  # pragma: no cover
@@ -85,6 +88,7 @@ def get(
         *,
         locale: str = DEFAULT_LOCALE,
         tzinfo: Optional[TZ_EXPR] = None,
+        fold: Optional[int] = None,
         normalize_whitespace: bool = False,
     ) -> Arrow:
         ...  # pragma: no cover
@@ -96,6 +100,11 @@ def get(self, *args: Any, **kwargs: Any) -> Arrow:
         :param tzinfo: (optional) a :ref:`timezone expression <tz-expr>` or tzinfo object.
             Replaces the timezone unless using an input form that is explicitly UTC or specifies
             the timezone in a positional argument. Defaults to UTC.
+        :param fold: (optional) an ``int`` value of 0 or 1.
+            Replaces the fold value, used to disambiguate repeated wall times.
+            Used only when the first argument is an Arrow instance/datetime/datetime string,
+            or datetime constructor kwargs were provided.
+
         :param normalize_whitespace: (optional) a ``bool`` specifying whether or not to normalize
             redundant whitespace (spaces, tabs, and newlines) in a datetime string before parsing.
             Defaults to false.
@@ -196,14 +205,19 @@ def get(self, *args: Any, **kwargs: Any) -> Arrow:
         arg_count = len(args)
         locale = kwargs.pop("locale", DEFAULT_LOCALE)
         tz = kwargs.get("tzinfo", None)
+        fold = kwargs.get("fold")
         normalize_whitespace = kwargs.pop("normalize_whitespace", False)
 
-        # if kwargs given, send to constructor unless only tzinfo provided
-        if len(kwargs) > 1:
+        # if kwargs given, send to constructor unless only tzinfo and/or fold provided
+        if len(kwargs) > 2:
+            arg_count = 3
+
+        # either tzinfo or fold kwarg is not provided
+        elif len(kwargs) == 2 and None in (tz, fold):
             arg_count = 3
 
-        # tzinfo kwarg is not provided
-        if len(kwargs) == 1 and tz is None:
+        # tzinfo and fold kwargs are both not provided
+        elif len(kwargs) == 1 and tz is fold is None:
             arg_count = 3
 
         # () -> now, @ tzinfo or utc
@@ -235,11 +249,11 @@ def get(self, *args: Any, **kwargs: Any) -> Arrow:
 
             # (Arrow) -> from the object's datetime @ tzinfo
             elif isinstance(arg, Arrow):
-                return self.type.fromdatetime(arg.datetime, tzinfo=tz)
+                return self.type.fromdatetime(arg.datetime, tzinfo=tz, fold=fold)
 
             # (datetime) -> from datetime @ tzinfo
             elif isinstance(arg, datetime):
-                return self.type.fromdatetime(arg, tzinfo=tz)
+                return self.type.fromdatetime(arg, tzinfo=tz, fold=fold)
 
             # (date) -> from date @ tzinfo
             elif isinstance(arg, date):
@@ -252,7 +266,7 @@ def get(self, *args: Any, **kwargs: Any) -> Arrow:
             # (str) -> parse @ tzinfo
             elif isinstance(arg, str):
                 dt = parser.DateTimeParser(locale).parse_iso(arg, normalize_whitespace)
-                return self.type.fromdatetime(dt, tzinfo=tz)
+                return self.type.fromdatetime(dt, tzinfo=tz, fold=fold)
 
             # (struct_time) -> from struct_time
             elif isinstance(arg, struct_time):
@@ -274,7 +288,7 @@ def get(self, *args: Any, **kwargs: Any) -> Arrow:
 
                 # (datetime, tzinfo/str) -> fromdatetime @ tzinfo
                 if isinstance(arg_2, (dt_tzinfo, str)):
-                    return self.type.fromdatetime(arg_1, tzinfo=arg_2)
+                    return self.type.fromdatetime(arg_1, tzinfo=arg_2, fold=fold)
                 else:
                     raise TypeError(
                         f"Cannot parse two arguments of types 'datetime', {type(arg_2)!r}."
@@ -295,7 +309,7 @@ def get(self, *args: Any, **kwargs: Any) -> Arrow:
                 dt = parser.DateTimeParser(locale).parse(
                     args[0], args[1], normalize_whitespace
                 )
-                return self.type.fromdatetime(dt, tzinfo=tz)
+                return self.type.fromdatetime(dt, tzinfo=tz, fold=fold)
 
             else:
                 raise TypeError(

tests/test_arrow.py

@@ -74,9 +74,6 @@ def test_init_with_fold(self):
         before = arrow.Arrow(2017, 10, 29, 2, 0, tzinfo="Europe/Stockholm")
         after = arrow.Arrow(2017, 10, 29, 2, 0, tzinfo="Europe/Stockholm", fold=1)
 
-        assert hasattr(before, "fold")
-        assert hasattr(after, "fold")
-
         # PEP-495 requires the comparisons below to be true
         assert before == after
         assert before.utcoffset() != after.utcoffset()
@@ -183,6 +180,14 @@ def test_strptime(self):
             2013, 2, 3, 12, 30, 45, tzinfo=tz.gettz("Europe/Paris")
         )
 
+    def test_strptime_with_fold(self):
+
+        formatted = datetime(2013, 2, 3, 12, 30, 45).strftime("%Y-%m-%d %H:%M:%S")
+
+        result = arrow.Arrow.strptime(formatted, "%Y-%m-%d %H:%M:%S", fold=1)
+        assert result._datetime == datetime(2013, 2, 3, 12, 30, 45, tzinfo=tz.tzutc())
+        assert result.fold == 1
+
     def test_fromordinal(self):
 
         timestamp = 1607066909.937968

tests/test_factory.py

@@ -97,12 +97,31 @@ def test_one_arg_arrow(self):
 
         assert arw == result
 
+    def test_one_arg_arrow_with_fold(self):
+
+        arw = self.factory.utcnow()
+        result = self.factory.get(arw, fold=1)
+
+        # fold is ignored for comparison
+        assert arw.fold == 0
+        assert result.fold == 1
+        assert arw == result
+
     def test_one_arg_datetime(self):
 
         dt = datetime.utcnow().replace(tzinfo=tz.tzutc())
 
         assert self.factory.get(dt) == dt
 
+    def test_one_arg_datetime_with_fold(self):
+
+        dt = datetime.utcnow().replace(tzinfo=tz.tzutc())
+        result = self.factory.get(dt, fold=1)
+
+        assert dt.fold == 0
+        assert result.fold == 1
+        assert result == dt
+
     def test_one_arg_date(self):
 
         d = date.today()