ENH: rewrite backports from Python std lib in a fashion that can be a…

…utomatically cleaned up with pyupgrade

yt/geometry/geometry_handler.py

@@ -16,6 +16,24 @@
 )
 
 
+def cached_chunk_property(func):
+    n = f"_{func.__name__}"
+
+    def cached_func(self):
+        if self._cache and getattr(self, n, None) is not None:
+            return getattr(self, n)
+        if self.data_size is None:
+            tr = self._accumulate_values(n[1:])
+        else:
+            tr = func(self)
+        if self._cache:
+
+            setattr(self, n, tr)
+        return tr
+
+    return property(cached_func)
+
+
 class Index(ParallelAnalysisInterface, abc.ABC):
     """The base index class"""
 
@@ -243,26 +261,6 @@ def _chunk(self, dobj, chunking_style, ngz=0, **kwargs):
             raise NotImplementedError
 
 
-def cached_property(func):
-    # TODO: remove this once minimal supported version of Python reaches 3.8
-    # and replace with functools.cached
-    n = f"_{func.__name__}"
-
-    def cached_func(self):
-        if self._cache and getattr(self, n, None) is not None:
-            return getattr(self, n)
-        if self.data_size is None:
-            tr = self._accumulate_values(n[1:])
-        else:
-            tr = func(self)
-        if self._cache:
-
-            setattr(self, n, tr)
-        return tr
-
-    return property(cached_func)
-
-
 class YTDataChunk:
     def __init__(
         self,
@@ -298,7 +296,7 @@ def _accumulate_values(self, method):
         self.data_size = arrs.shape[0]
         return arrs
 
-    @cached_property
+    @cached_chunk_property
     def fcoords(self):
         if self._fast_index is not None:
             ci = self._fast_index.select_fcoords(self.dobj.selector, self.data_size)
@@ -317,7 +315,7 @@ def fcoords(self):
             ind += c.shape[0]
         return ci
 
-    @cached_property
+    @cached_chunk_property
     def icoords(self):
         if self._fast_index is not None:
             ci = self._fast_index.select_icoords(self.dobj.selector, self.data_size)
@@ -334,7 +332,7 @@ def icoords(self):
             ind += c.shape[0]
         return ci
 
-    @cached_property
+    @cached_chunk_property
     def fwidth(self):
         if self._fast_index is not None:
             ci = self._fast_index.select_fwidth(self.dobj.selector, self.data_size)
@@ -353,7 +351,7 @@ def fwidth(self):
             ind += c.shape[0]
         return ci
 
-    @cached_property
+    @cached_chunk_property
     def ires(self):
         if self._fast_index is not None:
             ci = self._fast_index.select_ires(self.dobj.selector, self.data_size)
@@ -370,12 +368,12 @@ def ires(self):
             ind += c.size
         return ci
 
-    @cached_property
+    @cached_chunk_property
     def tcoords(self):
         self.dtcoords
         return self._tcoords
 
-    @cached_property
+    @cached_chunk_property
     def dtcoords(self):
         ct = np.empty(self.data_size, dtype="float64")
         cdt = np.empty(self.data_size, dtype="float64")
@@ -392,7 +390,7 @@ def dtcoords(self):
             ind += gt.size
         return cdt
 
-    @cached_property
+    @cached_chunk_property
     def fcoords_vertex(self):
         nodes_per_elem = self.dobj.index.meshes[0].connectivity_indices.shape[1]
         dim = self.dobj.ds.dimensionality

yt/visualization/plot_window.py

@@ -1,3 +1,4 @@
+import sys
 from collections import defaultdict
 from functools import wraps
 from numbers import Number
@@ -48,18 +49,11 @@
 )
 from .plot_modifications import callback_registry
 
-import sys  # isort: skip
-
 if sys.version_info < (3, 10):
-    # this function is deprecated in more_itertools
-    # because it is superseded by the standard library
     from more_itertools import zip_equal
 else:
 
     def zip_equal(*args):
-        # FUTURE: when only Python 3.10+ is supported,
-        # drop this conditional and call the builtin zip
-        # function directly where due
         return zip(*args, strict=True)
 
 

yt/visualization/volume_rendering/old_camera.py

@@ -1,12 +1,12 @@
 import builtins
+import sys
 from copy import deepcopy
 
 import numpy as np
 
 from yt.config import ytcfg
 from yt.data_objects.api import ImageArray
 from yt.funcs import ensure_numpy_array, get_num_threads, get_pbar, is_sequence, mylog
-from yt.geometry.geometry_handler import cached_property
 from yt.units.yt_array import YTArray
 from yt.utilities.amr_kdtree.api import AMRKDTree
 from yt.utilities.exceptions import YTNotInsideNotebook
@@ -35,6 +35,27 @@
 
 from .transfer_functions import ProjectionTransferFunction
 
+if sys.version_info >= (3, 8):
+    from functools import cached_property
+else:
+
+    def cached_property(func):
+        n = f"_{func.__name__}"
+
+        def cached_func(self):
+            if self._cache and getattr(self, n, None) is not None:
+                return getattr(self, n)
+            if self.data_size is None:
+                tr = self._accumulate_values(n[1:])
+            else:
+                tr = func(self)
+            if self._cache:
+
+                setattr(self, n, tr)
+            return tr
+
+        return property(cached_func)
+
 
 def get_corners(le, re):
     return np.array(