Merge branch 'main' into gh-136053/memory-saferty-TYPE_SLICE

Author: akshat62

Doc/c-api/capsule.rst

@@ -105,9 +105,19 @@ Refer to :ref:`using-capsules` for more information on using these objects.
    ``module.attribute``.  The *name* stored in the capsule must match this
    string exactly.
 
+   This function splits *name* on the ``.`` character, and imports the first
+   element. It then processes further elements using attribute lookups.
+
    Return the capsule's internal *pointer* on success.  On failure, set an
    exception and return ``NULL``.
 
+   .. note::
+
+      If *name* points to an attribute of some submodule or subpackage, this
+      submodule or subpackage must be previously imported using other means
+      (for example, by using :c:func:`PyImport_ImportModule`) for the
+      attribute lookups to succeed.
+
    .. versionchanged:: 3.3
       *no_block* has no effect anymore.
 

Doc/library/math.rst

@@ -59,6 +59,7 @@ noted otherwise, all return values are floats.
 :func:`isnan(x) <isnan>`                              Check if *x* is a NaN  (not a number)
 :func:`ldexp(x, i) <ldexp>`                           ``x * (2**i)``, inverse of function :func:`frexp`
 :func:`nextafter(x, y, steps) <nextafter>`            Floating-point value *steps* steps after *x* towards *y*
+:func:`signbit(x) <signbit>`                          Check if *x* is a negative number
 :func:`ulp(x) <ulp>`                                  Value of the least significant bit of *x*
 
 **Power, exponential and logarithmic functions**
@@ -431,6 +432,15 @@ Floating point manipulation functions
       Added the *steps* argument.
 
 
+.. function:: signbit(x)
+
+   Return ``True`` if the sign of *x* is negative and ``False`` otherwise.
+
+   This is useful to detect the sign bit of zeroes, infinities and NaNs.
+
+   .. versionadded:: next
+
+
 .. function:: ulp(x)
 
    Return the value of the least significant bit of the float *x*:

Doc/whatsnew/3.15.rst

@@ -115,6 +115,9 @@ math
 * Add :func:`math.isnormal` and :func:`math.issubnormal` functions.
   (Contributed by Sergey B Kirpichev in :gh:`132908`.)
 
+* Add :func:`math.signbit` function.
+  (Contributed by Bénédikt Tran in :gh:`135853`.)
+
 
 os.path
 -------

Include/internal/pycore_global_objects_fini_generated.h

@@ -627,6 +627,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(offset_src)
         STRUCT_FOR_ID(on_type_read)
         STRUCT_FOR_ID(onceregistry)
+        STRUCT_FOR_ID(only_active_thread)
         STRUCT_FOR_ID(only_keys)
         STRUCT_FOR_ID(oparg)
         STRUCT_FOR_ID(opcode)

Include/internal/pycore_global_strings.h

@@ -7,7 +7,7 @@
 import threading
 from asyncio import staggered, taskgroups, base_events, tasks
 from unittest.mock import ANY
-from test.support import os_helper, SHORT_TIMEOUT, busy_retry
+from test.support import os_helper, SHORT_TIMEOUT, busy_retry, requires_gil_enabled
 from test.support.script_helper import make_script
 from test.support.socket_helper import find_unused_port
 
@@ -876,6 +876,126 @@ def test_self_trace(self):
             ],
         )
 
+    @skip_if_not_supported
+    @unittest.skipIf(
+        sys.platform == "linux" and not PROCESS_VM_READV_SUPPORTED,
+        "Test only runs on Linux with process_vm_readv support",
+    )
+    @requires_gil_enabled("Free threaded builds don't have an 'active thread'")
+    def test_only_active_thread(self):
+        # Test that only_active_thread parameter works correctly
+        port = find_unused_port()
+        script = textwrap.dedent(
+            f"""\
+            import time, sys, socket, threading
+
+            # Connect to the test process
+            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            sock.connect(('localhost', {port}))
+
+            def worker_thread(name, barrier, ready_event):
+                barrier.wait()  # Synchronize thread start
+                ready_event.wait()  # Wait for main thread signal
+                # Sleep to keep thread alive
+                time.sleep(10_000)
+
+            def main_work():
+                # Do busy work to hold the GIL
+                sock.sendall(b"working\\n")
+                count = 0
+                while count < 100000000:
+                    count += 1
+                    if count % 10000000 == 0:
+                        pass  # Keep main thread busy
+                sock.sendall(b"done\\n")
+
+            # Create synchronization primitives
+            num_threads = 3
+            barrier = threading.Barrier(num_threads + 1)  # +1 for main thread
+            ready_event = threading.Event()
+
+            # Start worker threads
+            threads = []
+            for i in range(num_threads):
+                t = threading.Thread(target=worker_thread, args=(f"Worker-{{i}}", barrier, ready_event))
+                t.start()
+                threads.append(t)
+
+            # Wait for all threads to be ready
+            barrier.wait()
+
+            # Signal ready to parent process
+            sock.sendall(b"ready\\n")
+
+            # Signal threads to start waiting
+            ready_event.set()
+
+            # Give threads time to start sleeping
+            time.sleep(0.1)
+
+            # Now do busy work to hold the GIL
+            main_work()
+            """
+        )
+
+        with os_helper.temp_dir() as work_dir:
+            script_dir = os.path.join(work_dir, "script_pkg")
+            os.mkdir(script_dir)
+
+            # Create a socket server to communicate with the target process
+            server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            server_socket.bind(("localhost", port))
+            server_socket.settimeout(SHORT_TIMEOUT)
+            server_socket.listen(1)
+
+            script_name = _make_test_script(script_dir, "script", script)
+            client_socket = None
+            try:
+                p = subprocess.Popen([sys.executable, script_name])
+                client_socket, _ = server_socket.accept()
+                server_socket.close()
+
+                # Wait for ready signal
+                response = b""
+                while b"ready" not in response:
+                    response += client_socket.recv(1024)
+
+                # Wait for the main thread to start its busy work
+                while b"working" not in response:
+                    response += client_socket.recv(1024)
+
+                # Get stack trace with all threads
+                unwinder_all = RemoteUnwinder(p.pid, all_threads=True)
+                all_traces = unwinder_all.get_stack_trace()
+
+                # Get stack trace with only GIL holder
+                unwinder_gil = RemoteUnwinder(p.pid, only_active_thread=True)
+                gil_traces = unwinder_gil.get_stack_trace()
+
+            except PermissionError:
+                self.skipTest(
+                    "Insufficient permissions to read the stack trace"
+                )
+            finally:
+                if client_socket is not None:
+                    client_socket.close()
+                p.kill()
+                p.terminate()
+                p.wait(timeout=SHORT_TIMEOUT)
+
+            # Verify we got multiple threads in all_traces
+            self.assertGreater(len(all_traces), 1, "Should have multiple threads")
+
+            # Verify we got exactly one thread in gil_traces
+            self.assertEqual(len(gil_traces), 1, "Should have exactly one GIL holder")
+
+            # The GIL holder should be in the all_traces list
+            gil_thread_id = gil_traces[0][0]
+            all_thread_ids = [trace[0] for trace in all_traces]
+            self.assertIn(gil_thread_id, all_thread_ids,
+                         "GIL holder should be among all threads")
+
 
 if __name__ == "__main__":
     unittest.main()

Include/internal/pycore_runtime_init_generated.h

@@ -475,6 +475,19 @@ def testCopysign(self):
         # similarly, copysign(2., NAN) could be 2. or -2.
         self.assertEqual(abs(math.copysign(2., NAN)), 2.)
 
+    def test_signbit(self):
+        self.assertRaises(TypeError, math.signbit)
+        self.assertRaises(TypeError, math.signbit, '1.0')
+
+        # C11, §7.12.3.6 requires signbit() to return a nonzero value
+        # if and only if the sign of its argument value is negative,
+        # but in practice, we are only interested in a boolean value.
+        self.assertIsInstance(math.signbit(1.0), bool)
+
+        for arg in [0., 1., INF, NAN]:
+            self.assertFalse(math.signbit(arg))
+            self.assertTrue(math.signbit(-arg))
+
     def testCos(self):
         self.assertRaises(TypeError, math.cos)
         self.ftest('cos(-pi/2)', math.cos(-math.pi/2), 0, abs_tol=math.ulp(1))
@@ -1387,7 +1400,6 @@ def __rmul__(self, other):
         args = ((-5, -5, 10), (1.5, 4611686018427387904, 2305843009213693952))
         self.assertEqual(sumprod(*args), 0.0)
 
-
     @requires_IEEE_754
     @unittest.skipIf(HAVE_DOUBLE_ROUNDING,
                          "sumprod() accuracy not guaranteed on machines with double rounding")
@@ -2486,7 +2498,6 @@ def test_nextafter(self):
         with self.assertRaises(ValueError):
             math.nextafter(1.0, INF, steps=-1)
 
-
     @requires_IEEE_754
     def test_ulp(self):
         self.assertEqual(math.ulp(1.0), sys.float_info.epsilon)

Include/internal/pycore_unicodeobject_generated.h

@@ -0,0 +1,2 @@
+:mod:`math`: expose C99 :func:`~math.signbit` function to determine whether
+the sign bit of a floating-point value is set. Patch by Bénédikt Tran.