Python 3.7 last-rites x 1.

This commit is the first in a commit chain **last-riting** (i.e.,
permanently removing) support for Python 3.7, which recently hit its
official End-of-Life (EoL) date and thus constitutes a security risk.
Since Python 3.7 substantially differed from Python 3.8 with respect to
type hints in general and the standard `typing` module in specific, this
commit chain is likely to take longer than anyone wants or expects. This
is why @leycec does @beartype: so you don't have to. (*Broad roads, bro!*)

beartype/_cave/_cavefast.py

@@ -45,7 +45,6 @@
 from beartype._cave._caveabc import BoolType
 from beartype._util.py.utilpyversion import (
     IS_PYTHON_AT_LEAST_3_9,
-    IS_PYTHON_AT_LEAST_3_8,
 )
 from collections import deque as _deque
 from collections.abc import (
@@ -86,6 +85,7 @@
 from types import (
     AsyncGeneratorType as _AsyncGeneratorType,
     BuiltinFunctionType as _BuiltinFunctionType,
+    CellType as _CellType,
     CoroutineType as _CoroutineType,
     FrameType as _FrameType,
     FunctionType as _FunctionType,
@@ -219,53 +219,15 @@ class by that name. To circumvents this obvious oversight, this global globally
 '''
 
 
-# If the active Python interpreter targets Python >= 3.8...
-if IS_PYTHON_AT_LEAST_3_8:
-    # Defer version-specific imports.
-    from types import CellType as _CellType  # type: ignore[attr-defined]
-
-    # Alias this type to this standard type.
-    #
-    # Note that this is explicitly required for "nuitka" support, which supports
-    # this standard type but *NOT* the non-standard approach used to deduce this
-    # type under Python 3.7 leveraged below.
-    ClosureVarCellType = _CellType
-    '''
-    Type of all **pure-Python closure cell variables.**
-    '''
-# Else, the active Python interpreter only targets Python 3.7. In this case...
-else:
-    def _closure_varcell_factory():
-        '''
-        Arbitrary function returning a closure-specific cell variable exposed by
-        an arbitrary closure isolated to this function.
-        '''
-
-        # Arbitrary outer local variable.
-        cell_variable = 42
-
-        def closure():
-            '''
-            Arbitrary closure exposing a closure-specific cell variable.
-            '''
-
-            nonlocal cell_variable
-
-        return closure.__closure__[0]  # pyright: ignore[reportOptionalSubscript]
-
-
-    # Although Python >= 3.7 now exposes an explicit closure cell variable type
-    # via the standard "types.CellType" object, this is of no benefit to older
-    # versions of Python. Ergo, the type of an arbitrary method wrapper
-    # guaranteed to *ALWAYS* exist is obtained instead.
-    ClosureVarCellType = type(_closure_varcell_factory())  # type: ignore[misc]
-    '''
-    Type of all **pure-Python closure cell variables.**
-    '''
-
-
-    # Delete this factory function for safety.
-    del _closure_varcell_factory
+# Alias this type to this standard type.
+#
+# Note that this is explicitly required for "nuitka" support, which supports
+# this standard type but *NOT* the non-standard approach used to deduce this
+# type under Python 3.7 leveraged below.
+ClosureVarCellType = _CellType
+'''
+Type of all **pure-Python closure cell variables.**
+'''
 
 # ....................{ TYPES ~ call : exception           }....................
 ExceptionTracebackType = _TracebackType

beartype/_util/py/utilpyversion.py

@@ -15,7 +15,20 @@
 # ....................{ CONSTANTS ~ at least               }....................
 IS_PYTHON_AT_LEAST_4_0 = version_info >= (4, 0)
 '''
-``True`` only if the active Python interpreter targets at least Python 4.0.0.
+:data:`True` only if the active Python interpreter targets at least Python
+4.0.0.
+'''
+
+
+#FIXME: After dropping Python 3.12 support:
+#* Refactor all code conditionally testing this global to be unconditional.
+#* Remove this global.
+#* Remove all decorators resembling:
+#  @skip_if_python_version_less_than('3.12.0')
+IS_PYTHON_AT_LEAST_3_12 = IS_PYTHON_AT_LEAST_4_0 or version_info >= (3, 12)
+'''
+:data:`True` only if the active Python interpreter targets at least Python
+3.12.0.
 '''
 
 
@@ -24,17 +37,20 @@
 #* Remove this global.
 #* Remove all decorators resembling:
 #  @skip_if_python_version_less_than('3.11.0')
-IS_PYTHON_AT_LEAST_3_11 = IS_PYTHON_AT_LEAST_4_0 or version_info >= (3, 11)
+IS_PYTHON_AT_LEAST_3_11 = IS_PYTHON_AT_LEAST_3_12 or version_info >= (3, 11)
 '''
-``True`` only if the active Python interpreter targets at least Python 3.11.0.
+:data:`True` only if the active Python interpreter targets at least Python
+3.11.0.
 '''
 
 
 #FIXME: After dropping Python 3.9 support:
+#* Refactor all code conditionally testing this global to be unconditional.
 #* Remove this global.
 IS_PYTHON_AT_MOST_3_10 = not IS_PYTHON_AT_LEAST_3_11
 '''
-``True`` only if the active Python interpreter targets at most Python 3.10.x.
+:data:`True` only if the active Python interpreter targets at most Python
+3.10.x.
 '''
 
 
@@ -45,15 +61,17 @@
 #  @skip_if_python_version_less_than('3.10.0')
 IS_PYTHON_AT_LEAST_3_10 = IS_PYTHON_AT_LEAST_3_11 or version_info >= (3, 10)
 '''
-``True`` only if the active Python interpreter targets at least Python 3.10.0.
+:data:`True` only if the active Python interpreter targets at least Python
+3.10.0.
 '''
 
 
 #FIXME: After dropping Python 3.9 support:
+#* Refactor all code conditionally testing this global to be unconditional.
 #* Remove this global.
 IS_PYTHON_AT_MOST_3_9 = not IS_PYTHON_AT_LEAST_3_10
 '''
-``True`` only if the active Python interpreter targets at most Python 3.9.x.
+:data:`True` only if the active Python interpreter targets at most Python 3.9.x.
 '''
 
 
@@ -64,15 +82,17 @@
 #  @skip_if_python_version_less_than('3.9.0')
 IS_PYTHON_AT_LEAST_3_9 = IS_PYTHON_AT_LEAST_3_10 or version_info >= (3, 9)
 '''
-``True`` only if the active Python interpreter targets at least Python 3.9.0.
+:data:`True` only if the active Python interpreter targets at least Python
+3.9.0.
 '''
 
 
 #FIXME: After dropping Python 3.8 support:
+#* Refactor all code conditionally testing this global to be unconditional.
 #* Remove this global.
 IS_PYTHON_AT_MOST_3_8 = not IS_PYTHON_AT_LEAST_3_9
 '''
-``True`` only if the active Python interpreter targets at most Python 3.8.x.
+:data:`True` only if the active Python interpreter targets at most Python 3.8.x.
 '''
 
 
@@ -83,36 +103,17 @@
 #  @skip_if_python_version_less_than('3.8.0')
 IS_PYTHON_AT_LEAST_3_8 = IS_PYTHON_AT_LEAST_3_9 or version_info >= (3, 8)
 '''
-``True`` only if the active Python interpreter targets at least Python 3.8.0.
+:data:`True` only if the active Python interpreter targets at least Python
+3.8.0.
 '''
 
 
-#FIXME: After dropping Python 3.8 support, *REMOVE* all code conditionally
-#testing this global.
-IS_PYTHON_3_8 = version_info[:2] == (3, 8)
-'''
-``True`` only if the active Python interpreter targets exactly Python 3.8.
-'''
-
-
-#FIXME: After dropping Python 3.7 support:
+#FIXME: After dropping Python 3.8 support:
 #* Refactor all code conditionally testing this global to be unconditional.
 #* Remove this global.
-#* Remove all decorators resembling:
-#  @skip_if_python_version_less_than('3.7.2')
-IS_PYTHON_AT_LEAST_3_7_2 = IS_PYTHON_AT_LEAST_3_8 or version_info >= (3, 7, 2)
-'''
-``True`` only if the active Python interpreter targets at least Python 3.7.2,
-which introduced several new public attributes to the :mod:`typing` module
-(e.g., :attr:`typing.OrderedDict`).
-'''
-
-
-#FIXME: After dropping Python 3.7 support, *REMOVE* all code conditionally
-#testing this global.
-IS_PYTHON_3_7 = version_info[:2] == (3, 7)
+IS_PYTHON_3_8 = version_info[:2] == (3, 8)
 '''
-``True`` only if the active Python interpreter targets exactly Python 3.7.
+:data:`True` only if the active Python interpreter targets exactly Python 3.8.x.
 '''
 
 # ....................{ GETTERS                            }....................

beartype/typing/__init__.py

@@ -138,7 +138,6 @@
     IS_PYTHON_AT_LEAST_3_10  as _IS_PYTHON_AT_LEAST_3_10,
     IS_PYTHON_AT_LEAST_3_9   as _IS_PYTHON_AT_LEAST_3_9,
     IS_PYTHON_AT_LEAST_3_8   as _IS_PYTHON_AT_LEAST_3_8,
-    IS_PYTHON_AT_LEAST_3_7_2 as _IS_PYTHON_AT_LEAST_3_7_2,
 )
 
 # ....................{ IMPORTS ~ all                      }....................
@@ -335,6 +334,7 @@
         MutableMapping as MutableMapping,
         MutableSequence as MutableSequence,
         MutableSet as MutableSet,
+        OrderedDict as OrderedDict,
         Pattern as Pattern,
         Reversible as Reversible,
         Set as Set,
@@ -343,14 +343,6 @@
         Sequence as Sequence,
         ValuesView as ValuesView,
     )
-
-    # If the active Python interpreter targets Python >= 3.7.2, import *ALL*
-    # public attributes of the "typing" module introduced by Python 3.7.2
-    # deprecated by PEP 585 as their original values.
-    if _IS_PYTHON_AT_LEAST_3_7_2:
-        from typing import (  # type: ignore[attr-defined]
-            OrderedDict as OrderedDict,
-        )
 # If the active Python interpreter targets Python >= 3.9 and thus supports PEP
 # 585, alias *ALL* public attributes of the "typing" module deprecated by PEP
 # 585 to their equivalent values elsewhere in the standard library.

beartype/typing/_typingpep544.py

@@ -46,9 +46,6 @@
 # but couldn't find it after a brief search.
 if IS_PYTHON_AT_LEAST_3_8:
     # ..................{ IMPORTS                            }..................
-    #FIXME: The ignore[attr-defined] is for Python 3.7 because Mypy doesn't
-    #understand IS_PYTHON_AT_LEAST_3_8. That ignore should be removable
-    #when retiring PYTHON 3.7.
     # Defer Python version-specific imports, including non-caching
     # protocols to be overridden by caching equivalents below (and other
     # requirements from various sources, depending on runtime environment).