Merge branch 'main' into bpo-15987

Doc/c-api/hash.rst

@@ -29,6 +29,12 @@ See also the :c:member:`PyTypeObject.tp_hash` member and :ref:`numeric-hash`.
 
    .. versionadded:: 3.13
 
+.. c:macro:: PyHASH_MULTIPLIER
+
+   Prime multiplier used in string and various other hashes.
+
+   .. versionadded:: 3.13
+
 .. c:macro:: PyHASH_INF
 
    The hash value returned for a positive infinity.

Include/cpython/pyhash.h

@@ -3,7 +3,7 @@
 #endif
 
 /* Prime multiplier used in string and various other hashes. */
-#define _PyHASH_MULTIPLIER 1000003UL  /* 0xf4243 */
+#define PyHASH_MULTIPLIER 1000003UL  /* 0xf4243 */
 
 /* Parameters used for the numeric hash implementation.  See notes for
    _Py_HashDouble in Python/pyhash.c.  Numeric hashes are based on
@@ -17,9 +17,10 @@
 
 #define PyHASH_MODULUS (((size_t)1 << _PyHASH_BITS) - 1)
 #define PyHASH_INF 314159
-#define PyHASH_IMAG _PyHASH_MULTIPLIER
+#define PyHASH_IMAG PyHASH_MULTIPLIER
 
 /* Aliases kept for backward compatibility with Python 3.12 */
+#define _PyHASH_MULTIPLIER PyHASH_MULTIPLIER
 #define _PyHASH_BITS PyHASH_BITS
 #define _PyHASH_MODULUS PyHASH_MODULUS
 #define _PyHASH_INF PyHASH_INF

Lib/test/test_itertools.py

@@ -546,7 +546,7 @@ def test_count(self):
         #check proper internal error handling for large "step' sizes
         count(1, maxsize+5); sys.exc_info()
 
-    def test_count_with_stride(self):
+    def test_count_with_step(self):
         self.assertEqual(lzip('abc',count(2,3)), [('a', 2), ('b', 5), ('c', 8)])
         self.assertEqual(lzip('abc',count(start=2,step=3)),
                          [('a', 2), ('b', 5), ('c', 8)])
@@ -590,6 +590,28 @@ def test_count_with_stride(self):
         self.assertEqual(type(next(c)), int)
         self.assertEqual(type(next(c)), float)
 
+    @threading_helper.requires_working_threading()
+    def test_count_threading(self, step=1):
+        # this test verifies multithreading consistency, which is
+        # mostly for testing builds without GIL, but nice to test anyway
+        count_to = 10_000
+        num_threads = 10
+        c = count(step=step)
+        def counting_thread():
+            for i in range(count_to):
+                next(c)
+        threads = []
+        for i in range(num_threads):
+            thread = threading.Thread(target=counting_thread)
+            thread.start()
+            threads.append(thread)
+        for thread in threads:
+            thread.join()
+        self.assertEqual(next(c), count_to * num_threads * step)
+
+    def test_count_with_step_threading(self):
+        self.test_count_threading(step=5)
+
     def test_cycle(self):
         self.assertEqual(take(10, cycle('abc')), list('abcabcabca'))
         self.assertEqual(list(cycle('')), [])