atexit handler results in exceptions from half-torn-down-modules

[nedbat]

Originally reported by Zooko O'Whielacronx (Bitbucket: zooko, GitHub: zooko)

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This problem is exercised by the trialcoverage unit tests:

http://tahoe-lafs.org/trac/trialcoverage

Get trialcoverage and run "python setup.py test" to run trialcoverage's own self-tests which (on my machine) result in ...

Oh darn it now I can't reproduce it. It was giving me exceptions from code that was being run by the atexit handler when the module had been partially torn down so that, for example, the name "sorted" in coverage/data.py was None. I worked-around it by editing my copy of coverage/data.py to say "if sorted is None:" then just return and don't attempt to write out line_data.

Oh look! One of the Tahoe-LAFS buildbots is demonstrating the problem right now:

http://tahoe-lafs.org/buildbot/builders/Kyle%20OpenBSD-4.6%20amd64/builds/210/steps/test-coverage/logs/stdio

That buildbot is currently using these versions of coverage.py and trialcoverage:

http://tahoe-lafs.org/buildbot/builders/Kyle%20OpenBSD-4.6%20amd64/builds/210/steps/show-tool-versions/logs/stdio

That build ends with this stack trace:

Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/control.py", line 302, in save
    self.data.write(suffix=data_suffix)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 83, in write
    self.write_file(filename)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 111, in write_file
    data['lines'] = self.line_data()
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 96, in line_data
    [(f, sorted(lmap.keys())) for f, lmap in self.lines.items()]
TypeError: 'NoneType' object is not callable
Error in sys.exitfunc:
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/control.py", line 302, in save
    self.data.write(suffix=data_suffix)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 83, in write
    self.write_file(filename)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 111, in write_file
    data['lines'] = self.line_data()
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 96, in line_data
    [(f, sorted(lmap.keys())) for f, lmap in self.lines.items()]
TypeError: 'NoneType' object is not callable

coverage: [coverage 3.3.2a1z11 (/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg)]

trialcoverage: [trialcoverage 0.3.10 (/usr/local/lib/python2.6/site-packages/trialcoverage-0.3.10-py2.6.egg), setuptools 0.6c11 (/usr/local/lib/python2.6/site-packages/setuptools-0.6c11-py2.6.egg), pyutil 1.7.5 (/usr/local/lib/python2.6/site-packages/pyutil-1.7.5-py2.6.egg), coverage 3.3.2a1z11 (/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg), simplejson 2.1.1 (/usr/local/lib/python2.6/site-packages/simplejson-2.1.1-py2.6-openbsd-4.6-amd64.egg), zbase32 1.1.1 (/usr/local/lib/python2.6/site-packages/zbase32-1.1.1-py2.6.egg), argparse 0.9.1 (/usr/local/lib/python2.6/site-packages/argparse-0.9.1-py2.6.egg)]

I'll bet the reason that I can't reproduce it is that the trialcoverage self-tests currently pass and that this problem is triggered only when the tests are exiting in the failure state, as they are in that buildbot example.

---

• Bitbucket: https://bitbucket.org/ned/coveragepy/issue/71

[nedbat]

Original comment by Zooko O'Whielacronx (Bitbucket: zooko, GitHub: zooko)

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I've added a silly kludge to trialcoverage to make this stop happening on the Tahoe-LAFS buildslave:

http://tahoe-lafs.org/trac/trialcoverage/changeset/20100607061547-92b7f-e40a6cb2d01e37ccc6217d4c2d3279f450866122

[nedbat]

Original comment by Zooko O'Whielacronx (Bitbucket: zooko, GitHub: zooko)

---

Oh look the atexit hook causes these problems even on success tests in some cases:

http://tahoe-lafs.org/buildbot/builders/Kyle%20OpenBSD-4.6%20amd64/builds/227/steps/test-coverage/logs/stdio

Ends with:

Ran 795 tests in 717.507s

PASSED (skips=15, expectedFailures=1, successes=779)
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/control.py", line 302, in save
    self.data.write(suffix=data_suffix)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 83, in write
    self.write_file(filename)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 111, in write_file
    data['lines'] = self.line_data()
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 96, in line_data
    [(f, sorted(lmap.keys())) for f, lmap in self.lines.items()]
TypeError: 'NoneType' object is not callable
Error in sys.exitfunc:
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/control.py", line 302, in save
    self.data.write(suffix=data_suffix)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 83, in write
    self.write_file(filename)
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 111, in write_file
    data['lines'] = self.line_data()
  File "/usr/local/lib/python2.6/site-packages/coverage-3.3.2a1z11-py2.6-openbsd-4.6-amd64.egg/coverage/data.py", line 96, in line_data
    [(f, sorted(lmap.keys())) for f, lmap in self.lines.items()]
TypeError: 'NoneType' object is not callable

I've already asked the owner of that buildslave to install trialcoverage-0.3.11 which has by aforementioned kludge to disable the atexit handlers.

[nedbat]

Original comment by Zooko O'Whielacronx (Bitbucket: zooko, GitHub: zooko)

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This happened again on a different buildslave:

http://tahoe-lafs.org/buildbot/builders/Zooko%20zomp%20Mac-amd64%2010.6%20py2.6/builds/0/steps/test-coverage/logs/stdio

Unfortunately I need to make it stop doing this so that this won't interfere with the imminent release of Tahoe-LAFS v1.7.0β, so I'm going to upgrade that buildslave from trialcoverage-1.3.8-2 to trialcoverage-1.3.12, which will have the "disable atexit hook" work-around in it...

[nedbat]

Original comment by Zooko O'Whielacronx (Bitbucket: zooko, GitHub: zooko)

---

You can see build #1 which is a rebuild of the exact same Tahoe-LAFS source code as build #0 -- the only difference is that I upgraded trialcoverage:

http://tahoe-lafs.org/buildbot/builders/Zooko%20zomp%20Mac-amd64%2010.6%20py2.6/builds/1

You can see the version numbers of the tools here:

http://tahoe-lafs.org/buildbot/builders/Zooko%20zomp%20Mac-amd64%2010.6%20py2.6/builds/0/steps/show-tool-versions

http://tahoe-lafs.org/buildbot/builders/Zooko%20zomp%20Mac-amd64%2010.6%20py2.6/builds/1/steps/show-tool-versions

[nedbat]

I encountered tracebacks like this, and fixed them in <<changeset 04ebfac37f33 (bb)>>. I think this bug is fixed.