`xsd:boolean(...)` cast of `"NaN"^^xsd:double` returns `true`

[ting668]

Version

6.2.0

What happened?

Reporter: ting668

Environment

• Apache Jena Version: 6.2.0
• Java Version: 21.0.12+8-LTS

Description

While testing Apache Jena using an intuitive approach inspired by attribute constraints, I found that the numeric-to-boolean constructor returns true for a NaN double: xsd:boolean("NaN"^^xsd:double) evaluates to true, so a FILTER on the cast accepts a row it should reject.

Under the numeric-to-boolean cast, NaN and zero are false and non-zero values are true: 1.0 (as xsd:double or xsd:float) is true, while "NaN"^^xsd:double and "0.0"^^xsd:double are false.

How to Reproduce and Expected Behavior

Note: The queries below are a minimized, simplified example reproducing the bug.

Buggy query (with the default graph loaded with the N-Triples data below):

SELECT ?s WHERE { ?s <urn:pub:p> ?v . FILTER(<http://www.w3.org/2001/XMLSchema#boolean>(?v)) } ORDER BY ?s

Data (default graph, N-Triples):

<urn:pub:nanDouble> <urn:pub:p> "NaN"^^<http://www.w3.org/2001/XMLSchema#double> .
<urn:pub:zeroDouble> <urn:pub:p> "0.0"^^<http://www.w3.org/2001/XMLSchema#double> .
<urn:pub:oneDouble> <urn:pub:p> "1.0"^^<http://www.w3.org/2001/XMLSchema#double> .
<urn:pub:nanFloat> <urn:pub:p> "NaN"^^<http://www.w3.org/2001/XMLSchema#float> .
<urn:pub:oneFloat> <urn:pub:p> "1.0"^^<http://www.w3.org/2001/XMLSchema#float> .
<urn:pub:background> <urn:pub:other> <urn:pub:value> .

Expected behavior: only the 1.0 values cast to true:

[{"s":"<urn:pub:oneDouble>"},{"s":"<urn:pub:oneFloat>"}]

Actual behavior: the row carrying "NaN"^^xsd:double is also returned:

[{"s":"<urn:pub:nanDouble>"},{"s":"<urn:pub:oneDouble>"},{"s":"<urn:pub:oneFloat>"}]

In the same run the "NaN"^^xsd:float value was not accepted; the wrong true result was observed for the xsd:double NaN.

This suggests that the boolean cast of an xsd:double does not apply the specified mapping of NaN to false, so a value that should be rejected passes the filter.

Relevant output and stacktrace

Are you interested in making a pull request?

None

[afs]

Confirmed.