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21fbd57d66
Python 2.4 changed ntpath.abspath to do an import inside the function. As a result, due to Python's import lock, anything calling abspath on Windows (directly, or indirectly like tempfile.TemporaryFile) hung when it was called from a thread spawned as a side effect of importing a module. This is a depressingly frequent problem, and deserves a more general fix. I'm settling for a micro-fix here because this specific one accounts for a report of Zope Corp's ZEO hanging on Windows, and it was an odd way to change abspath to begin with (ntpath needs a different implementation depending on whether we're actually running on Windows, and the _obvious_ way to arrange for that is not to bury a possibly-failing import _inside_ the function). Note that if/when other micro-fixes of this kind get made, the new Lib/test/threaded_import_hangers.py is a convenient place to add tests for them.
42 lines
1.4 KiB
Python
42 lines
1.4 KiB
Python
# This is a helper module for test_threaded_import. The test imports this
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# module, and this module tries to run various Python library functions in
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# their own thread, as a side effect of being imported. If the spawned
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# thread doesn't complete in TIMEOUT seconds, an "appeared to hang" message
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# is appended to the module-global `errors` list. That list remains empty
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# if (and only if) all functions tested complete.
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TIMEOUT = 10
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import threading
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import tempfile
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import os.path
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errors = []
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# This class merely runs a function in its own thread T. The thread importing
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# this module holds the import lock, so if the function called by T tries
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# to do its own imports it will block waiting for this module's import
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# to complete.
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class Worker(threading.Thread):
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def __init__(self, function, args):
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threading.Thread.__init__(self)
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self.function = function
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self.args = args
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def run(self):
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self.function(*self.args)
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for name, func, args in [
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# Bug 147376: TemporaryFile hung on Windows, starting in Python 2.4.
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("tempfile.TemporaryFile", tempfile.TemporaryFile, ()),
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# The real cause for bug 147376: ntpath.abspath() caused the hang.
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("os.path.abspath", os.path.abspath, ('.',)),
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]:
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t = Worker(func, args)
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t.start()
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t.join(TIMEOUT)
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if t.isAlive():
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errors.append("%s appeared to hang" % name)
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