bpo-28009: Fix SkipUnless logic to be based on platform programs capable of introspection #12777
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Misc/NEWS.d/next/Tests/2019-04-11-07-59-43.bpo-28009.s85urF.rst
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FYI: one of the reasons I split this out - to address existing test issues only - is because a slightly hardened AIX server (using AIX standard tools) fails when the arp command is not SUID. So, in order to also run on a hardened server, e.g., as a bot that is not root, this change is actually high impact (for AIX). |
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p.s. This is a real "security" issue - in that when the tests run on a hardened AIX server (e.g., using aixpert or PowerSC) python consumes lots of resources, stalling the server, and ultimately core dumps. To prevent this on my bot I had to "undo" some of the hardening. If there are Python concerns with this PR - please comment so that those concerns may be resolved and the PR becomes acceptable. Thx! |
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Just a reminder - I made this PR because my bot was failing miserably after I had performed some basic system hardening. Without it the system will hang until python (test_uuid) crashes. |
… capable of introspection (pythonGH-12777) uuid could try fallback methods that had no chance of working on a particular platform, and this could cause spurious test failures, as well as degraded performance as fallback options were tried and failed. This fixes both the uuid module and its test's SkipUnless logic to use a prefiltered list of techniques that may at least potentially work on that platform. Patch by Michael Felt (aixtools). (cherry picked from commit 3a1d50e) Co-authored-by: Michael Felt <aixtools@users.noreply.github.com>
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GH-14115 is a backport of this pull request to the 3.8 branch. |
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Thanks for the change and the updated comments - they make it a lot clearer what is going on :) |
… capable of introspection (GH-12777) uuid could try fallback methods that had no chance of working on a particular platform, and this could cause spurious test failures, as well as degraded performance as fallback options were tried and failed. This fixes both the uuid module and its test's SkipUnless logic to use a prefiltered list of techniques that may at least potentially work on that platform. Patch by Michael Felt (aixtools). (cherry picked from commit 3a1d50e) Co-authored-by: Michael Felt <aixtools@users.noreply.github.com>
… capable of introspection (pythonGH-12777) uuid could try fallback methods that had no chance of working on a particular platform, and this could cause spurious test failures, as well as degraded performance as fallback options were tried and failed. This fixes both the uuid module and its test's SkipUnless logic to use a prefiltered list of techniques that may at least potentially work on that platform. Patch by Michael Felt (aixtools).
… capable of introspection (pythonGH-12777) uuid could try fallback methods that had no chance of working on a particular platform, and this could cause spurious test failures, as well as degraded performance as fallback options were tried and failed. This fixes both the uuid module and its test's SkipUnless logic to use a prefiltered list of techniques that may at least potentially work on that platform. Patch by Michael Felt (aixtools).
Thanks for a suggestion - for a better way @ncoghlan
Rather than try and get everything in one PR - a mountain to steep for me - I am going to take what I hope is the most simple part of my previous PR's on this PR8672 - still open and PR5183 (which I closed and started over again).
I will continue on PR8672 - but there the focus will be on Lib/uuid.py rather than Lib/test/test_uuid.py
I expect comments:
a) I am using platform.system() rather than sys.platform(.startswith)
b) I have identified four specific platforms (AIX, Darwin, Linux, Windows). Maybe more is needed, or a different default definition for _NODE_GETTERS when not a recognized platform.
c) prepending either _unix_getnode, or windll_getnode to NODE_GETTERS rather than repeat it several times. Not sure what is most "PEP8" specification.
d) In the class BaseTestInternals I removed the statement "uuid = None", better replaced it with _uuid = py_uuid so that the skipUnless statements could find what they need. Maybe "uuid = None" is still needed. However, it seems to unreferenced (as self.uuid is used for the selection of internal or external uuid module actually called)
In the hope this can move forward in steps - the patch focusing on SkipUnless - and getting the real commands that need to be tested right (in NODE_GETTERS).
https://bugs.python.org/issue28009