bpo-42222: Modernize integer test/conversion in randrange()

Lib/random.py

@@ -51,6 +51,7 @@
 from math import tau as TWOPI, floor as _floor, isfinite as _isfinite
 from os import urandom as _urandom
 from _collections_abc import Set as _Set, Sequence as _Sequence
+from operator import index as _index
 from itertools import accumulate as _accumulate, repeat as _repeat
 from bisect import bisect as _bisect
 import os as _os
@@ -297,28 +298,58 @@ def randrange(self, start, stop=None, step=1):
 
         # This code is a bit messy to make it fast for the
         # common case while still doing adequate error checking.
-        istart = int(start)
-        if istart != start:
-            raise ValueError("non-integer arg 1 for randrange()")
+        try:
+            istart = _index(start)
+        except TypeError:
+            if int(start) == start:
+                istart = int(start)
+                _warn('Float arguments to randrange() have been deprecated\n'
+                      'since Python 3.10 and will be removed in a subsequent '
+                      'version.',
+                      DeprecationWarning, 2)
+            else:
+                _warn('randrange() will raise TypeError in the future',
+                      DeprecationWarning, 2)
+                raise ValueError("non-integer arg 1 for randrange()")
         if stop is None:
             if istart > 0:
                 return self._randbelow(istart)
             raise ValueError("empty range for randrange()")
 
         # stop argument supplied.
-        istop = int(stop)
-        if istop != stop:
-            raise ValueError("non-integer stop for randrange()")
+        try:
+            istop = _index(stop)
+        except TypeError:
+            if int(stop) == stop:
+                istop = int(stop)
+                _warn('Float arguments to randrange() have been deprecated\n'
+                      'since Python 3.10 and will be removed in a subsequent '
+                      'version.',
+                      DeprecationWarning, 2)
+            else:
+                _warn('randrange() will raise TypeError in the future',
+                      DeprecationWarning, 2)
+                raise ValueError("non-integer stop for randrange()")
         width = istop - istart
         if step == 1 and width > 0:
             return istart + self._randbelow(width)
         if step == 1:
             raise ValueError("empty range for randrange() (%d, %d, %d)" % (istart, istop, width))
 
         # Non-unit step argument supplied.
-        istep = int(step)
-        if istep != step:
-            raise ValueError("non-integer step for randrange()")
+        try:
+            istep = _index(step)
+        except TypeError:
+            if int(step) == step:
+                istep = int(step)
+                _warn('Float arguments to randrange() have been deprecated\n'
+                      'since Python 3.10 and will be removed in a subsequent '
+                      'version.',
+                      DeprecationWarning, 2)
+            else:
+                _warn('randrange() will raise TypeError in the future',
+                      DeprecationWarning, 2)
+                raise ValueError("non-integer step for randrange()")
         if istep > 0:
             n = (width + istep - 1) // istep
         elif istep < 0:

Misc/NEWS.d/next/Library/2020-10-31-10-28-32.bpo-42222.Cfl1eR.rst

@@ -0,0 +1 @@
+Modernized integer test/conversion in randrange() to use operator.index().