GH 1868 zero-length paths must not match absent nodes#4032
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ThomasThelen wants to merge 2 commits into
Open
GH 1868 zero-length paths must not match absent nodes#4032ThomasThelen wants to merge 2 commits into
ThomasThelen wants to merge 2 commits into
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rvesse
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Jul 2, 2026
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Fix looks quite straightforward and elegant to me, it's been a while since I've been delving in the SPARQL engine internals so I will leave this open for now to give others with fresher eyes chance to review before merging
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I'd like time to explore all the possibilities with complex paths to convince myself that pulling the test up to the evaluation is always correct. (Finding clear "think" time is hard.) |
afs
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Jul 2, 2026
| protected static final int hashShortest = 0x205 ; | ||
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| // Return true if this path can match in zero steps |
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This isn't necessary because it is a default method in the interface.
(and it generates a warning because there is no @Override.)
Co-authored-by: Andy Seaborne <andy@apache.org>
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GitHub issue resolved #1868
Pull request Description:
This is a bit of an experimental path taken. Initially I had done this with a longer walking of the AST and realized that the performance hit would be too big because
evalGroundedPathgets called on each binding.Instead, the approach that I took here is to hardcode the zero length component state as part of the various path classes, culminating in the dispatch to evalGroundedPath. This should get called once rather than the n times for each row in my previous AST implementation.
Happy to provide performance tests, address feedback, or close this if it's a bit far fetched.
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