[New-bugs-announce] [issue20367] concurrent.futures.as_completed() fails when given duplicate Futures

[Glenn Langford]

New submission from Glenn Langford:

concurrent.futures.as_completed([f,f]) will yield f twice, then fail with a KeyError for a Future f which is not completed.

If the Future has already completed, as_completed([f,f]) will yield f once and does not trigger an exception.

What is the correct behaviour?
   as_completed( [f,f] ) -> yield f twice ?
   wait( [f,f], return_when=ALL_COMPLETED ) -> yield f twice ?

----------
components: Library (Lib)
files: test_dupfuture.py
messages: 208952
nosy: glangford
priority: normal
severity: normal
status: open
title: concurrent.futures.as_completed() fails when given duplicate Futures
type: behavior
versions: Python 3.3, Python 3.4
Added file: http://bugs.python.org/file33658/test_dupfuture.py

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue20367>
_______________________________________