move pairwise to compat

Author: tybug

hypothesis-python/src/hypothesis/internal/compat.py

@@ -12,6 +12,7 @@
 import copy
 import dataclasses
 import inspect
+import itertools
 import platform
 import sys
 import sysconfig
@@ -251,6 +252,20 @@ def bad_django_TestCase(runner):
         return not isinstance(runner, HypothesisTestCase)
 
 
+if sys.version_info[:2] < (3, 10):
+
+    # copied straight from
+    # https://docs.python.org/3/library/itertools.html#itertools.pairwise
+    def pairwise(iterable):
+        iterator = iter(iterable)
+        a = next(iterator, None)
+        for b in iterator:
+            yield a, b
+            a = b
+
+else:
+    pairwise = itertools.pairwise
+
 # see issue #3812
 if sys.version_info[:2] < (3, 12):
 

hypothesis-python/src/hypothesis/internal/conjecture/junkdrawer.py

@@ -15,7 +15,7 @@
 import array
 import sys
 import warnings
-from itertools import chain, pairwise
+from itertools import chain
 from random import Random
 from typing import (
     Callable,
@@ -35,6 +35,7 @@
 from sortedcontainers import SortedList
 
 from hypothesis.errors import HypothesisWarning
+from hypothesis.internal.compat import pairwise
 
 ARRAY_CODES = ["B", "H", "I", "L", "Q", "O"]