[Python-checkins] cpython (2.7): Issue #12157: pool.map() does not handle empty iterable correctly
richard.oudkerk
python-checkins at python.org
Thu Jun 7 21:42:06 CEST 2012
http://hg.python.org/cpython/rev/7ab7836894c4
changeset: 77377:7ab7836894c4
branch: 2.7
parent: 77371:d79c837b6bf3
user: Richard Oudkerk <shibturn at gmail.com>
date: Wed Jun 06 17:52:18 2012 +0100
summary:
Issue #12157: pool.map() does not handle empty iterable correctly
Initial patch by mouad
files:
Lib/multiprocessing/pool.py | 1 +
Lib/test/test_multiprocessing.py | 18 +++++++++++++++---
Misc/NEWS | 3 +++
3 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -576,6 +576,7 @@
if chunksize <= 0:
self._number_left = 0
self._ready = True
+ del cache[self._job]
else:
self._number_left = length//chunksize + bool(length % chunksize)
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
@@ -1152,6 +1152,18 @@
join()
self.assertTrue(join.elapsed < 0.2)
+ def test_empty_iterable(self):
+ # See Issue 12157
+ p = self.Pool(1)
+
+ self.assertEqual(p.map(sqr, []), [])
+ self.assertEqual(list(p.imap(sqr, [])), [])
+ self.assertEqual(list(p.imap_unordered(sqr, [])), [])
+ self.assertEqual(p.map_async(sqr, []).get(), [])
+
+ p.close()
+ p.join()
+
def unpickleable_result():
return lambda: 42
@@ -2113,7 +2125,7 @@
'Queue', 'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore',
'Condition', 'Event', 'Value', 'Array', 'RawValue',
'RawArray', 'current_process', 'active_children', 'Pipe',
- 'connection', 'JoinableQueue'
+ 'connection', 'JoinableQueue', 'Pool'
)))
testcases_processes = create_test_cases(ProcessesMixin, type='processes')
@@ -2127,7 +2139,7 @@
locals().update(get_attributes(manager, (
'Queue', 'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore',
'Condition', 'Event', 'Value', 'Array', 'list', 'dict',
- 'Namespace', 'JoinableQueue'
+ 'Namespace', 'JoinableQueue', 'Pool'
)))
testcases_manager = create_test_cases(ManagerMixin, type='manager')
@@ -2141,7 +2153,7 @@
'Queue', 'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore',
'Condition', 'Event', 'Value', 'Array', 'current_process',
'active_children', 'Pipe', 'connection', 'dict', 'list',
- 'Namespace', 'JoinableQueue'
+ 'Namespace', 'JoinableQueue', 'Pool'
)))
testcases_threads = create_test_cases(ThreadsMixin, type='threads')
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -67,6 +67,9 @@
Library
-------
+- Issue #12157: Make pool.map() empty iterables correctly. Initial
+ patch by mouad.
+
- Issue #14962: Update text coloring in IDLE shell window after changing
options. Patch by Roger Serwy.
--
Repository URL: http://hg.python.org/cpython
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