Revert changes to cython code base

Author: fjetter

pandas/_libs/properties.pyx

@@ -23,29 +23,12 @@ cdef class CachedProperty:
             return self
 
         # Get the cache or set a default one if needed
-        cache = instance_cache = getattr(obj, '_cache', None)
-
+        cache = getattr(obj, '_cache', None)
         if cache is None:
             try:
                 cache = obj._cache = {}
             except (AttributeError):
-                raise TypeError(
-                    f"Cython extension type {type(obj)} must declare attribute "
-                    "`_cache` to use @cache_readonly."
-                )
-
-        if instance_cache is not None:
-            # When accessing cython extension types, the attribute is already
-            # registered and known to the class, unlike for python object. To
-            # ensure we're not accidentally using a global scope / class level
-            # cache we'll need to check whether the instance and class
-            # attribute is identical
-            cache_class = getattr(typ, "_cache", None)
-            if cache_class is not None and cache_class is instance_cache:
-                raise TypeError(
-                    f"Class {typ} defines a `_cache` attribute on class level "
-                    "which is forbidden in combination with @cache_readonly."
-                )
+                return self
 
         if PyDict_Contains(cache, self.name):
             # not necessary to Py_INCREF

pandas/_libs/tslibs/offsets.pyx

@@ -895,6 +895,13 @@ cdef class Tick(SingleConstructorOffset):
 
         raise ApplyTypeError(f"Unhandled type: {type(other).__name__}")
 
+    # --------------------------------------------------------------------
+    # Pickle Methods
+
+    def __setstate__(self, state):
+        self.n = state["n"]
+        self.normalize = False
+
 
 cdef class Day(Tick):
     _nanos_inc = 24 * 3600 * 1_000_000_000
@@ -1998,6 +2005,11 @@ cdef class QuarterOffset(SingleConstructorOffset):
             startingMonth = self._default_starting_month
         self.startingMonth = startingMonth
 
+    cpdef __setstate__(self, state):
+        self.startingMonth = state.pop("startingMonth")
+        self.n = state.pop("n")
+        self.normalize = state.pop("normalize")
+
     @classmethod
     def _from_name(cls, suffix=None):
         kwargs = {}
@@ -2253,6 +2265,11 @@ cdef class SemiMonthOffset(SingleConstructorOffset):
                 f"got {self.day_of_month}"
             )
 
+    cpdef __setstate__(self, state):
+        self.n = state.pop("n")
+        self.normalize = state.pop("normalize")
+        self.day_of_month = state.pop("day_of_month")
+
     @classmethod
     def _from_name(cls, suffix=None):
         return cls(day_of_month=suffix)
@@ -2570,6 +2587,12 @@ cdef class WeekOfMonth(WeekOfMonthMixin):
         if self.week < 0 or self.week > 3:
             raise ValueError(f"Week must be 0<=week<=3, got {self.week}")
 
+    cpdef __setstate__(self, state):
+        self.n = state.pop("n")
+        self.normalize = state.pop("normalize")
+        self.weekday = state.pop("weekday")
+        self.week = state.pop("week")
+
     def _get_offset_day(self, other: datetime) -> int:
         """
         Find the day in the same month as other that has the same
@@ -2629,6 +2652,12 @@ cdef class LastWeekOfMonth(WeekOfMonthMixin):
         if self.n == 0:
             raise ValueError("N cannot be 0")
 
+    cpdef __setstate__(self, state):
+        self.n = state.pop("n")
+        self.normalize = state.pop("normalize")
+        self.weekday = state.pop("weekday")
+        self.week = -1
+
     def _get_offset_day(self, other: datetime) -> int:
         """
         Find the day in the same month as other that has the same
@@ -2680,6 +2709,12 @@ cdef class FY5253Mixin(SingleConstructorOffset):
         if self.variation not in ["nearest", "last"]:
             raise ValueError(f"{self.variation} is not a valid variation")
 
+    cpdef __setstate__(self, state):
+        self.n = state.pop("n")
+        self.normalize = state.pop("normalize")
+        self.weekday = state.pop("weekday")
+        self.variation = state.pop("variation")
+
     def is_anchored(self) -> bool:
         return (
             self.n == 1 and self.startingMonth is not None and self.weekday is not None
@@ -2960,6 +2995,10 @@ cdef class FY5253Quarter(FY5253Mixin):
         )
         self.qtr_with_extra_week = qtr_with_extra_week
 
+    cpdef __setstate__(self, state):
+        FY5253Mixin.__setstate__(self, state)
+        self.qtr_with_extra_week = state.pop("qtr_with_extra_week")
+
     @cache_readonly
     def _offset(self):
         return FY5253(
@@ -3102,6 +3141,10 @@ cdef class Easter(SingleConstructorOffset):
     Right now uses the revised method which is valid in years 1583-4099.
     """
 
+    cpdef __setstate__(self, state):
+        self.n = state.pop("n")
+        self.normalize = state.pop("normalize")
+
     @apply_wraps
     def apply(self, other: datetime) -> datetime:
         current_easter = easter(other.year)

pandas/tests/libs/test_lib.py

@@ -4,7 +4,6 @@
 from pandas._libs import (
     Timestamp,
     lib,
-    properties,
     writers as libwriters,
 )
 
@@ -213,48 +212,3 @@ def test_no_default_pickle():
     # GH#40397
     obj = tm.round_trip_pickle(lib.no_default)
     assert obj is lib.no_default
-
-
-def test_cache_readonly_no_global_cache():
-    """
-    Ensure that the definition of a global attribute `_cache` does
-    not interfere with the property cache
-    """
-
-    from typing import Dict
-
-    class MyDtypeGlobalAttr:
-        _cache: Dict = {}
-
-        def __init__(self, value):
-            self._value = value
-
-        @properties.cache_readonly
-        def cached_attr(self):
-            return self._value
-
-    a = MyDtypeGlobalAttr("A")
-    with pytest.raises(TypeError, match=r"defines a `_cache` attribute"):
-        a.cached_attr
-
-    class MyDtypeInstanceAttr:
-        def __init__(self, value):
-            self._value = value
-            self._cache = {}
-
-        @properties.cache_readonly
-        def cached_attr(self):
-            return self._value
-
-    a = MyDtypeInstanceAttr("A")
-    b = MyDtypeInstanceAttr("B")
-    b._cache = {}
-
-    # Assert our assumption that the property cache
-    # actually uses an attribute called _cache
-    assert len(a._cache) == 0
-
-    assert a.cached_attr == "A"
-    assert b.cached_attr == "B"
-
-    assert len(a._cache) == 1