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

…utomatically cleaned up with pyupgrade

yt/geometry/geometry_handler.py

@@ -1,5 +1,6 @@
 import abc
 import os
+import sys
 import weakref
 
 import numpy as np
@@ -15,6 +16,27 @@
     parallel_root_only,
 )
 
+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)
+
 
 class Index(ParallelAnalysisInterface, abc.ABC):
     """The base index class"""
@@ -243,26 +265,6 @@ 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,

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-    # because it is superseded by the standard library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(