Fix KeyError in Schematron When Handling Missing or Invalid Namespace Prefixes
#423
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Resolves an issue in the `lxml.isoschematron.Schematron` class where an unhandled KeyError was raised when `Schematron` is initialized with elements that have invalid or missing namespace prefixes. The KeyError occurred due to direct dictionary access without checking for the existence of the key. The changes introduced here: - Replace direct dictionary access with dict.get() to safely retrieve values from namespace maps, preventing KeyError on missing/invalid prefixes. - Enhance unit tests to cover cases where schemas lack proper namespace prefixes or contain incorrect namespace prefixes, ensuring robust error handling. Fixes: https://bugs.launchpad.net/lxml/+bug/2058177
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DaveLak
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May 29, 2024
The changes here update the `fuzz_sax` test harness to gracefully handle the exception so the fuzzer will not exit when the exception is raised and remove the special case handling in `fuzz_schematron.py` for a bug in `lxml.isoschematron.Schematron that has been fixed.` ## `fuzz_sax.py` The `IndexError` raised in `src/lxml/sax.py` is a known bug with an issue marked as low priority in lxml's bug tracker since 2023-03-14: https://bugs.launchpad.net/lxml/+bug/2011542 ## `fuzz_schematron.py` The unhandled `KeyError` bug in the `lxml.isoschematron.Schematron` class that was previously identified by fuzzing has been fixed upstream via: lxml/lxml#423.
DavidKorczynski
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May 29, 2024
The changes here update the `fuzz_sax` test harness to gracefully handle a documented exception so the fuzzer will not exit when the exception is raised. This PR also removes the special case handling in `fuzz_schematron.py` for a bug in `lxml.isoschematron.Schematron` that has been fixed. ## Changes to `fuzz_sax.py` The `IndexError` raised in `src/lxml/sax.py` is a known bug with an issue marked as low priority in lxml's bug tracker since 2023-03-14: https://bugs.launchpad.net/lxml/+bug/2011542 ## Changes to `fuzz_schematron.py` The unhandled `KeyError` bug in the `lxml.isoschematron.Schematron` class that was previously identified by fuzzing has been fixed upstream via: lxml/lxml#423.
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Fixes: https://bugs.launchpad.net/lxml/+bug/2058177
Resolves an issue in the
lxml.isoschematron.Schematronclass where an unhandled KeyError was raised whenSchematronis initialized with elements that have invalid or missing namespace prefixes. The KeyError occurred due to direct dictionary access without checking for the existence of the key.The changes introduced here: