An include or import cycle recursed without bound and crashed the
host with a stack overflow, reachable from stylesheet data. The
compile chain tracks the active load chain by resolved href and drops
re-entry, while diamond composition keeps loading both copies with
their own import precedences per 2.6.2. id() builds a per-document
index on first use instead of re-walking the document per call,
matching key(). Cycle and diamond regression tests added.
The XSLT layer's id() follows the XPath definition exactly: only
attributes the source's DTD declares as type ID identify elements
(internal or external subset, via the transform's resolver), and a
document without ID declarations yields the empty set. generate-id()
produces non-empty, distinct identifiers for attribute and namespace
nodes through their identity hash. Lookup implementations move to
XSLTLookups.swift for the file caps. Xalan baseline 131 -> 129.
Same-name xsl:attribute-set declarations merge as ordered definitions
per 7.1.4, each expanding its used sets before its own attributes with
later definitions winning; xsl:copy carries the source element's
in-scope namespace nodes per 7.5; the namespace fixup lets a carried
attribute prefix shadow an inherited binding unless the element's own
name relies on it; the html method minimizes boolean attributes whose
value repeats their name; and external DTDs and entities in the
stylesheet or source resolve through the transform's document loader.
Four unit tests pin the behaviors. Xalan baseline 174 -> 159
(attribset 13 -> 4, copy 12 -> 7).
key() resolves its index against the current node's own document,
built lazily per document root, so keys work inside document() trees;
a node-set use expression indexes the matched node under every
member's string value; and key() results return in document order
regardless of lookup value order. Xalan baseline 187 -> 182.
xsl:number implements all of XSLT 1.0 section 7.7: level
single/multiple/any with count and from matched as patterns through the
match cache, the value expression with the below-one bypass, and the
format-token engine (punctuation, separator and token reuse, zero
padding, alphabetic/roman/Greek sequences, digit grouping). An
unmatched single/multiple count renders empty; level=any always yields
a number. document() now caches per transform so repeated loads of the
same URI return the identical document and generate-id() stays unique
against live nodes (the idkey49 flake). Xalan baseline 557 -> 475
(numbering 84 -> 7).
