Fix relative IRIs containing a forward slash before a colon

[Copilot]

The relative-to-absolute-iri library treats any value containing a colon as absolute, without validating that the pre-colon segment is a valid URI scheme. Per RFC 3986, a scheme is ALPHA *( ALPHA / DIGIT / "+" / "-" / "." ) — slashes are forbidden — so x/y:z is unambiguously a relative IRI and must be resolved against the base IRI.

Changes

• lib/RdfXmlParser.ts: In valueToUri, detect when a slash precedes the first colon (ruling out a valid scheme). For such values, temporarily encode all colons as \u0000 (null character, illegal in XML and therefore safe as a sentinel), resolve against the base IRI, then restore the colons.

<!-- base IRI: https://example.com/base/ -->
<default:C rdf:about="x/y:z"/>
<!-- Previously resolved to: x/y:z (incorrect — treated as absolute) -->
<!-- Now resolves to: https://example.com/base/x/y:z (correct) -->

• test/RdfXmlParser-test.ts: Added unit tests for valueToUri covering slash-before-colon resolution (with/without trailing slash on base, multiple colons), and an integration test parsing a full RDF/XML document with such a relative IRI.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Relative IRIs containing a forward slash and a colon</issue_title>
<issue_description>Files that contain rdf:about="{x}/{y}:{z}" are incorrectly parsed ATM.

Example dataset:

<?xml version="1.0" encoding="UTF-8"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns="https://example.com/default/"
         xml:base="https://example.com/base/">
  <C rdf:about="x/y:z">
  </C>
</rdf:RDF>

The expected behavior / reproducible with Rapper is to parse the above as:

<https://example.com/base/x/y:z> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <https://example.com/default/C>.

Maybe x/y:z is considered a full IRI by the parser. If so, this is incorrect because the scheme component is not allowed to contain a forward slash (/). Therefore, x/y:z should be considered a relative IRI which must be made absolute.
</issue_description>

<agent_instructions>Could you fix this issue and provide a unit test for it?</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Relative IRIs containing a forward slash and a colon #45

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[coveralls]

Pull Request Test Coverage Report for Build 22686555487

Details

• 5 of 5 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 21170362124:	0.0%
Covered Lines:	372
Relevant Lines:	372

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💛 - Coveralls

[rubensworks]

Replaced by rubensworks/relative-to-absolute-iri.js#28