Issue #8407: signal.pthread_sigmask() returns a set instead of a list

Update the doc. Refactor also related tests.

Doc/library/signal.rst

@@ -184,7 +184,7 @@ The :mod:`signal` module defines the following functions:
 
    Fetch and/or change the signal mask of the calling thread.  The signal mask
    is the set of signals whose delivery is currently blocked for the caller.
-   The old signal mask is returned.
+   Return the old signal mask as a set of signals.
 
    The behavior of the call is dependent on the value of *how*, as follows.
 
@@ -196,8 +196,9 @@ The :mod:`signal` module defines the following functions:
     * :data:`SIG_SETMASK`: The set of blocked signals is set to the *mask*
       argument.
 
-   *mask* is a list of signal numbers (e.g. [:const:`signal.SIGINT`,
-   :const:`signal.SIGTERM`]).
+   *mask* is a set of signal numbers (e.g. {:const:`signal.SIGINT`,
+   :const:`signal.SIGTERM`}). Use ``range(1, signal.NSIG)`` for a full mask
+   including all signals.
 
    For example, ``signal.pthread_sigmask(signal.SIG_BLOCK, [])`` reads the
    signal mask of the calling thread.

Lib/test/test_signal.py

@@ -486,24 +486,27 @@ class ItimerTest(unittest.TestCase):
 
 @unittest.skipUnless(hasattr(signal, 'pthread_sigmask'),
                      'need signal.pthread_sigmask()')
-class PthreadSigmaskTests(unittest.TestCase):
-    def test_arguments(self):
+class PendingSignalsTests(unittest.TestCase):
+    """
+    Tests for the pthread_sigmask() function.
+    """
+    def handler(self, signum, frame):
+        1/0
+
+    def read_sigmask(self):
+        return signal.pthread_sigmask(signal.SIG_BLOCK, [])
+
+    def test_pthread_sigmask_arguments(self):
         self.assertRaises(TypeError, signal.pthread_sigmask)
         self.assertRaises(TypeError, signal.pthread_sigmask, 1)
         self.assertRaises(TypeError, signal.pthread_sigmask, 1, 2, 3)
         self.assertRaises(RuntimeError, signal.pthread_sigmask, 1700, [])
 
-    def test_block_unlock(self):
+    def test_pthread_sigmask(self):
         import faulthandler
         pid = os.getpid()
         signum = signal.SIGUSR1
 
-        def handler(signum, frame):
-            1/0
-
-        def read_sigmask():
-            return signal.pthread_sigmask(signal.SIG_BLOCK, [])
-
         # The fault handler timeout thread masks all signals. If the main
         # thread masks also SIGUSR1, all threads mask this signal. In this
         # case, if we send SIGUSR1 to the process, the signal is pending in the
@@ -527,7 +530,7 @@ class PthreadSigmaskTests(unittest.TestCase):
                   "blocked by pthread_sigmask() (issue #11998)")
 
         # Install our signal handler
-        old_handler = signal.signal(signum, handler)
+        old_handler = signal.signal(signum, self.handler)
         self.addCleanup(signal.signal, signum, old_handler)
 
         # Unblock SIGUSR1 (and copy the old mask) to test our signal handler
@@ -543,9 +546,9 @@ class PthreadSigmaskTests(unittest.TestCase):
             os.kill(pid, signum)
 
         # Check the new mask
-        blocked = read_sigmask()
+        blocked = self.read_sigmask()
         self.assertIn(signum, blocked)
-        self.assertEqual(set(old_mask) ^ set(blocked), {signum})
+        self.assertEqual(old_mask ^ blocked, {signum})
 
         # Unblock SIGUSR1
         if can_test_blocked_signals:
@@ -558,9 +561,9 @@ class PthreadSigmaskTests(unittest.TestCase):
             os.kill(pid, signum)
 
         # Check the new mask
-        unblocked = read_sigmask()
+        unblocked = self.read_sigmask()
         self.assertNotIn(signum, unblocked)
-        self.assertEqual(set(blocked) ^ set(unblocked), {signum})
+        self.assertEqual(blocked ^ unblocked, {signum})
         self.assertSequenceEqual(old_mask, unblocked)
         # Finally, restore the previous signal handler and the signal mask
 
@@ -570,7 +573,7 @@ def test_main():
         support.run_unittest(BasicSignalTests, InterProcessSignalTests,
                              WakeupSignalTests, SiginterruptTest,
                              ItimerTest, WindowsSignalTests,
-                             PthreadSigmaskTests)
+                             PendingSignalsTests)
     finally:
         support.reap_children()
 

Modules/signalmodule.c

@@ -552,37 +552,18 @@ error:
     return result;
 }
 
-static PyObject *
-signal_pthread_sigmask(PyObject *self, PyObject *args)
+static PyObject*
+sigset_to_set(sigset_t mask)
 {
-    int how, sig;
-    PyObject *signals, *result, *signum;
-    sigset_t mask, previous;
-    int err;
-
-    if (!PyArg_ParseTuple(args, "iO:pthread_sigmask", &how, &signals))
-        return NULL;
-
-    if (iterable_to_sigset(signals, &mask))
-        return NULL;
+    PyObject *signum, *result;
+    int sig;
 
-    err = pthread_sigmask(how, &mask, &previous);
-    if (err != 0) {
-        errno = err;
-        PyErr_SetFromErrno(PyExc_RuntimeError);
-        return NULL;
-    }
-
-    /* if signals was unblocked, signal handlers have been called */
-    if (PyErr_CheckSignals())
-        return NULL;
-
-    result = PyList_New(0);
+    result = PySet_New(0);
     if (result == NULL)
         return NULL;
 
     for (sig = 1; sig < NSIG; sig++) {
-        if (sigismember(&previous, sig) != 1)
+        if (sigismember(&mask, sig) != 1)
             continue;
 
         /* Handle the case where it is a member by adding the signal to
@@ -595,7 +576,7 @@ signal_pthread_sigmask(PyObject *self, PyObject *args)
             Py_DECREF(result);
             return NULL;
         }
-        if (PyList_Append(result, signum) == -1) {
+        if (PySet_Add(result, signum) == -1) {
             Py_DECREF(signum);
             Py_DECREF(result);
             return NULL;
@@ -605,6 +586,34 @@ signal_pthread_sigmask(PyObject *self, PyObject *args)
     return result;
 }
 
+static PyObject *
+signal_pthread_sigmask(PyObject *self, PyObject *args)
+{
+    int how;
+    PyObject *signals;
+    sigset_t mask, previous;
+    int err;
+
+    if (!PyArg_ParseTuple(args, "iO:pthread_sigmask", &how, &signals))
+        return NULL;
+
+    if (iterable_to_sigset(signals, &mask))
+        return NULL;
+
+    err = pthread_sigmask(how, &mask, &previous);
+    if (err != 0) {
+        errno = err;
+        PyErr_SetFromErrno(PyExc_RuntimeError);
+        return NULL;
+    }
+
+    /* if signals was unblocked, signal handlers have been called */
+    if (PyErr_CheckSignals())
+        return NULL;
+
+    return sigset_to_set(previous);
+}
+
 PyDoc_STRVAR(signal_pthread_sigmask_doc,
 "pthread_sigmask(how, mask) -> old mask\n\
 \n\