[Python-checkins] cpython (2.7): Issue #12285: multiprocessing.Pool() raises a ValueError if the number of

[victor.stinner]

http://hg.python.org/cpython/rev/815263546757
changeset:   70911:815263546757
branch:      2.7
parent:      70906:41a23277a35a
user:        Victor Stinner <victor.stinner at haypocalc.com>
date:        Mon Jun 20 17:54:33 2011 +0200
summary:
  Issue #12285: multiprocessing.Pool() raises a ValueError if the number of
processes if negative or null.

files:
  Lib/multiprocessing/pool.py      |  2 ++
  Lib/test/test_multiprocessing.py |  3 +++
  2 files changed, 5 insertions(+), 0 deletions(-)


diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -125,6 +125,8 @@
                 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
--- a/Lib/test/test_multiprocessing.py
+++ b/Lib/test/test_multiprocessing.py
@@ -1085,6 +1085,9 @@
         self.assertEqual(sorted(it), map(sqr, 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()

-- 
Repository URL: http://hg.python.org/cpython