diff options
| -rw-r--r-- | Doc/library/concurrent.futures.rst | 3 | ||||
| -rw-r--r-- | Lib/concurrent/futures/_base.py | 6 | ||||
| -rw-r--r-- | Lib/test/test_concurrent_futures.py | 7 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
4 files changed, 16 insertions, 3 deletions
diff --git a/Doc/library/concurrent.futures.rst b/Doc/library/concurrent.futures.rst index 93538e4..0495737 100644 --- a/Doc/library/concurrent.futures.rst +++ b/Doc/library/concurrent.futures.rst @@ -371,7 +371,8 @@ Module Functions Returns an iterator over the :class:`Future` instances (possibly created by different :class:`Executor` instances) given by *fs* that yields futures as - they complete (finished or were cancelled). Any futures that completed + they complete (finished or were cancelled). Any futures given by *fs* that + are duplicated will be returned once. Any futures that completed before :func:`as_completed` is called will be yielded first. The returned iterator raises a :exc:`TimeoutError` if :meth:`~iterator.__next__` is called and the result isn't available after *timeout* seconds from the diff --git a/Lib/concurrent/futures/_base.py b/Lib/concurrent/futures/_base.py index 3d03280..c3b1f01 100644 --- a/Lib/concurrent/futures/_base.py +++ b/Lib/concurrent/futures/_base.py @@ -181,7 +181,8 @@ def as_completed(fs, timeout=None): Returns: An iterator that yields the given Futures as they complete (finished or - cancelled). + cancelled). If any given Futures are duplicated, they will be returned + once. Raises: TimeoutError: If the entire result iterator could not be generated @@ -190,11 +191,12 @@ def as_completed(fs, timeout=None): if timeout is not None: end_time = timeout + time.time() + fs = set(fs) with _AcquireFutures(fs): finished = set( f for f in fs if f._state in [CANCELLED_AND_NOTIFIED, FINISHED]) - pending = set(fs) - finished + pending = fs - finished waiter = _create_and_install_waiters(fs, _AS_COMPLETED) try: diff --git a/Lib/test/test_concurrent_futures.py b/Lib/test/test_concurrent_futures.py index a7e945c..c74b2ca 100644 --- a/Lib/test/test_concurrent_futures.py +++ b/Lib/test/test_concurrent_futures.py @@ -350,6 +350,13 @@ class AsCompletedTests: SUCCESSFUL_FUTURE]), completed_futures) + def test_duplicate_futures(self): + # Issue 20367. Duplicate futures should not raise exceptions or give + # duplicate responses. + future1 = self.executor.submit(time.sleep, 2) + completed = [f for f in futures.as_completed([future1,future1])] + self.assertEqual(len(completed), 1) + class ThreadPoolAsCompletedTests(ThreadPoolMixin, AsCompletedTests, unittest.TestCase): pass @@ -36,6 +36,9 @@ Core and Builtins Library ------- +- Issue #20367: Fix behavior of concurrent.futures.as_completed() for + duplicate arguments. Patch by Glenn Langford. + - Issue #8260: The read(), readline() and readlines() methods of codecs.StreamReader returned incomplete data when were called after readline() or read(size). Based on patch by Amaury Forgeot d'Arc. |