unpickler: avoid holding on to external references #580
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Even though the unpickler goes out of scope immediately after decode() completes, the Python garbage collector is not able to determine that garbage collection can occur despite the fact that no references are being held. The observed behavior is that Python is not deleting the ephemeral unpickler instance. Make this easier for the GC to handle by explicitly resetting the ephemeral Unpickler instance at the end of decode(). This guarantees that no external references are being held and allows them to be cleaned up in a slightly more predictable fashion. The test case was added to the numpy test suite because triggering this behavior currently requires the numpy extension to be used. Closes: jsonpickle#579
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The most recent push added a test to ensure that this behaves as expected. I was only able to make the test fail when using numpy (as reported in #579) so I ended up adding the test to the numpy extension tests in |
Theelx
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Dec 9, 2025
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This is an surprisingly simple fix, thanks for this! I added my approval, but can you add a CHANGES.rst entry before merging it?
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* davvid/decode-gc: CHANGES: update release notes draft unpickler: avoid holding on to external references
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Thanks for reviewing! CHANGES.rst has been updated and I pushed a fixup commit to apply the latest code style to this commit. |
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Even though the unpickler goes out of scope immediately after decode() completes, the Python garbage collector is not able to determine that garbage collection can occur despite the fact that no references are being held. The observed behavior is that Python is not deleting the ephemeral unpickler instance.
Make this easier for the GC to handle by explicitly resetting the ephemeral Unpickler instance at the end of decode(). This guarantees that no external references are being held and allows them to be cleaned up in a slightly more predictable fashion.
Closes: #579