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author | Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> | 2019-06-11 09:01:20 -0700 |
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committer | GitHub <noreply@github.com> | 2019-06-11 09:01:20 -0700 |
commit | 5d1d4e3179ffd4d2d72462d870cf86dcc11450ce (patch) | |
tree | bc39c14ec9d4a95e641d1cac519d3d6d943955ff /Lib | |
parent | 1b615b2f035d207941e44259a92ed0bdcc56ac45 (diff) | |
download | cpython-git-5d1d4e3179ffd4d2d72462d870cf86dcc11450ce.tar.gz |
bpo-36607: Eliminate RuntimeError raised by asyncio.all_tasks() (GH-13971)
If internal tasks weak set is changed by another thread during iteration.
https://bugs.python.org/issue36607
(cherry picked from commit 65aa64fae89a24491aae84ba0329eb8f3c68c389)
Co-authored-by: Andrew Svetlov <andrew.svetlov@gmail.com>
Diffstat (limited to 'Lib')
-rw-r--r-- | Lib/asyncio/tasks.py | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py index 402c6e26a7..c82b95e3be 100644 --- a/Lib/asyncio/tasks.py +++ b/Lib/asyncio/tasks.py @@ -35,9 +35,22 @@ def all_tasks(loop=None): """Return a set of all tasks for the loop.""" if loop is None: loop = events.get_running_loop() - # NB: set(_all_tasks) is required to protect - # from https://bugs.python.org/issue34970 bug - return {t for t in list(_all_tasks) + # Looping over a WeakSet (_all_tasks) isn't safe as it can be updated from another + # thread while we do so. Therefore we cast it to list prior to filtering. The list + # cast itself requires iteration, so we repeat it several times ignoring + # RuntimeErrors (which are not very likely to occur). See issues 34970 and 36607 for + # details. + i = 0 + while True: + try: + tasks = list(_all_tasks) + except RuntimeError: + i += 1 + if i >= 1000: + raise + else: + break + return {t for t in tasks if futures._get_loop(t) is loop and not t.done()} @@ -47,9 +60,22 @@ def _all_tasks_compat(loop=None): # method. if loop is None: loop = events.get_event_loop() - # NB: set(_all_tasks) is required to protect - # from https://bugs.python.org/issue34970 bug - return {t for t in list(_all_tasks) if futures._get_loop(t) is loop} + # Looping over a WeakSet (_all_tasks) isn't safe as it can be updated from another + # thread while we do so. Therefore we cast it to list prior to filtering. The list + # cast itself requires iteration, so we repeat it several times ignoring + # RuntimeErrors (which are not very likely to occur). See issues 34970 and 36607 for + # details. + i = 0 + while True: + try: + tasks = list(_all_tasks) + except RuntimeError: + i += 1 + if i >= 1000: + raise + else: + break + return {t for t in tasks if futures._get_loop(t) is loop} class Task(futures._PyFuture): # Inherit Python Task implementation |