[bugfix] Forward port PR #6544: fix XSLT imports and document builder isolation

[line-o]

Summary

Forward port of PR #6544 from develop-6.x.x to develop, fixing critical issues with XSLT stylesheet resolution and document builder isolation in fn:transform. Adapted for Saxon 12.5 compatibility.

Fixes:

• Issue [BUG] Relative URL resolution not working as expected under XSLT in eXist 7 #5051: XSLT relative imports on exist 7
• Issue [BUG] test isolation in XQSuite #6065: Document builder isolation in concurrent fn:transform calls

What Changed

1. Document Builder Isolation (Delivery.java)

Problem: When multiple fn:transform calls execute in the same XQuery context, they share the same MemTreeBuilder. This causes output corruption when transforms execute concurrently.

Solution: Always use a fresh MemTreeBuilder for each transform result instead of reusing the context's builder.

2. Persistent Node Handling (Convert.java)

Problem: Persistent nodes stored in the database (NodeProxy instances) weren't properly dereferenced when passed as stylesheet parameters.

Solution:

• Check Document interface instead of specific DocumentImpl class
• Dereference NodeProxy to underlying DOM node in of(Sequence) method
• Enables passing database-stored nodes as stylesheet parameters

3. XSLT Stylesheet Resolution for Relative URIs (Issue #5052 - Root Cause Fix)

Root Causes (discovered during porting):

1. URIResolution.resolveURI(): Database paths like "/db/collection/stylesheet.xsl" were incorrectly treated as relative URIs because URI.isAbsolute() returns false (they lack a scheme component).

   • Fix: Treat database paths (starting with "/" or "xmldb:") as absolute for resolution purposes

2. URIResolution.resolveDocument(): Did not set SystemId on returned DOMSource objects. When Saxon resolved and loaded included stylesheets, it had no base URI for resolving further nested includes.

   • Fix: Set SystemId = location on all returned DOMSource objects

3. Options.resolvePossibleStylesheetLocation(): Simplified to use the resolved location directly as SystemId, ensuring consistent base URI setup for Saxon's compile-time resolver.

4. Other Changes

Transform.java: Updated createDestination() call sites to match new Delivery.java signature

Test Coverage

Two comprehensive XQSuite test modules verify all fixes:

• fnTransform5052.xqm (13 tests): Relative stylesheet resolution with xsl:include/xsl:import
• fnTransform6065.xqm (2 tests): Persistent database nodes as stylesheet parameters

Result: All 7110 tests pass with zero failures and zero errors.

[line-o]

I propose to squash all four commits

[bugfix] Forward port PR #6544: fix XSLT imports and document builder isolation

Fixes #5051 (XSLT import resolution) and #6065 (document builder isolation) by
porting and refining key changes from develop-6.x.x, adapted for Saxon 12.5.

## Document Builder Isolation (Issue #6065)
- Always use fresh MemTreeBuilder for fn:transform results instead of sharing
  the query context's builder
- Prevents corruption when multiple fn:transform calls occur in parallel within
  the same execution context
- Fixes concurrent transform output corruption

## Persistent Node Handling
- Handle persistent NodeProxy nodes by dereferencing to underlying DOM nodes
- Enables passing database-stored nodes as stylesheet parameters to fn:transform
- Uses Document interface checks instead of specific implementation classes

## Stylesheet Resolution for Relative xsl:include/xsl:import (Issue #5052)

Root cause analysis revealed three interconnected issues:

1. URIResolution.resolveURI() incorrectly treated database paths (starting with
   "/" or "xmldb:") as relative URIs because they lacked a scheme component.
   A path like "/db/collection/stylesheet.xsl" is an absolute path but not an
   absolute URI in the RFC 3986 sense. Fixed by checking for database path
   prefixes in addition to URI scheme.

2. URIResolution.resolveDocument() did not set SystemId on returned DOMSource
   objects. When Saxon resolved xsl:include/xsl:import hrefs and loaded
   included stylesheets, it had no base URI for resolving further nested
   includes. Fixed by setting SystemId = location on all returned sources.

3. Options.resolvePossibleStylesheetLocation() simplified to use the resolved
   location parameter directly as SystemId, ensuring consistent base URI setup
   for Saxon's compile-time URI resolver. This supports the chain:
   - Stylesheet at /db/coll/main.xsl
   - Includes sub/inc.xsl → resolved to /db/coll/sub/inc.xsl (base URI via SystemId)
   - Includes nested.xsl → resolved to /db/coll/sub/nested.xsl (base URI via SystemId)

## Convert.java
- Check Document interface instead of specific DocumentImpl implementation
- Add NodeProxy dereference in of(Sequence) method to handle persistent nodes

## Transform.java
- Updated createDestination() call sites for new Delivery.java signature

## Test Coverage
- fnTransform5052.xqm: 13 tests for relative xsl:include/xsl:import and
  stylesheet-location resolution in database-stored stylesheets
- fnTransform6065.xqm: 2 tests for persistent nodes as stylesheet parameters

All tests pass with exit code 0.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

[line-o]

@duncdrum pointed out that #5051 needs to be looked at in this context

[line-o]

Good catches will change code - wonder if this is covered by a codacy rule

[dizzzz]

what about #5051 ?

[line-o]

What about it? It's mentioned in description.

[line-o]

Is there something that blocks this PR I am not aware of?