Issue #12459: time.sleep() now raises a ValueError if the sleep length is

negative, instead of an infinite sleep on Windows or raising an IOError on
Linux for example, to have the same behaviour on all platforms.

Lib/test/test_time.py

@@ -27,6 +27,8 @@ class TimeTestCase(unittest.TestCase):
                          int(self.t))
 
     def test_sleep(self):
+        self.assertRaises(ValueError, time.sleep, -2)
+        self.assertRaises(ValueError, time.sleep, -1)
         time.sleep(1.2)
 
     def test_strftime(self):

Misc/NEWS

@@ -219,6 +219,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #12459: time.sleep() now raises a ValueError if the sleep length is
+  negative, instead of an infinite sleep on Windows or raising an IOError on
+  Linux for example, to have the same behaviour on all platforms.
+
 - Issue #12451: pydoc: html_getfile() now uses tokenize.open() to support
   Python scripts using a encoding different than UTF-8 (read the coding cookie
   of the script).

Modules/timemodule.c

@@ -141,6 +141,11 @@ time_sleep(PyObject *self, PyObject *args)
     double secs;
     if (!PyArg_ParseTuple(args, "d:sleep", &secs))
         return NULL;
+    if (secs < 0) {
+        PyErr_SetString(PyExc_ValueError,
+                        "sleep length must be non-negative");
+        return NULL;
+    }
     if (floatsleep(secs) != 0)
         return NULL;
     Py_INCREF(Py_None);