From 2fae27b735f4d93c8a7789a7a98857e1ce3c7193 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Mon, 20 Jun 2011 17:53:35 +0200 Subject: [PATCH] Issue #12285: multiprocessing.Pool() raises a ValueError if the number of processes if negative or null. --- Lib/multiprocessing/pool.py | 2 ++ Lib/test/test_multiprocessing.py | 3 +++ 2 files changed, 5 insertions(+) diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py index 92170f2ee8c..e450319d4f4 100644 --- a/Lib/multiprocessing/pool.py +++ b/Lib/multiprocessing/pool.py @@ -148,6 +148,8 @@ class Pool(object): processes = cpu_count() except NotImplementedError: processes = 1 + if processes < 1: + raise ValueError("Number of processes must be at least 1") if initializer is not None and not hasattr(initializer, '__call__'): raise TypeError('initializer must be a callable') diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py index 2614689bca9..dc41e151bf3 100644 --- a/Lib/test/test_multiprocessing.py +++ b/Lib/test/test_multiprocessing.py @@ -1089,6 +1089,9 @@ class _TestPool(BaseTestCase): self.assertEqual(sorted(it), list(map(sqr, list(range(1000))))) def test_make_pool(self): + self.assertRaises(ValueError, multiprocessing.Pool, -1) + self.assertRaises(ValueError, multiprocessing.Pool, 0) + p = multiprocessing.Pool(3) self.assertEqual(3, len(p._pool)) p.close()