[New-bugs-announce] [issue19425] multiprocessing.Pool.map hangs if pickling argument raises an exception

[Nadeem Vawda]

New submission from Nadeem Vawda:

[Split off from issue 19395]

The following code hangs after hitting a TypeError trying to pickle one
of the TextIOWrapper objects:

    import multiprocessing

    def read(f): return f.read()

    files = [open(path) for path in 3 * ['/dev/null']]
    pool = multiprocessing.Pool()
    results = pool.map(read, files)
    print(results)

This issue is present in 3.2, 3.3 and 3.4, but not in 2.7.

----------
components: Library (Lib)
messages: 201580
nosy: cantor, jnoller, nadeem.vawda, pitrou, python-dev, sbt, tim.peters
priority: normal
severity: normal
stage: needs patch
status: open
title: multiprocessing.Pool.map hangs if pickling argument raises an exception
type: behavior
versions: Python 3.3, Python 3.4

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue19425>
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