Extends the redefine self-reference rule (redefineSelfReferenceErrors, moved to
SchemaRedefineSelfReference.swift) to attribute groups: a group or attributeGroup
inside xs:redefine may reference itself at most once (src-redefine.6.1.1 /
7.2.1), and a group self-reference must occur exactly once. Catches a redefined
attributeGroup with two self-references (attgC044).
Fixes a latent false positive an adversarial review found in the group case: the
search now uses a BOUNDED walk (boundedSelfReferenceNodes) that stops at nested
element/complexType scopes, matching the established cycle-rule boundary. The
prior unbounded walk would miscount a recursive group reference inside a nested
element's content (a data-structure recursion, legal) as a redefinition
self-reference. attributeGroup content has no such nesting, so it is unaffected.
XSTS: invalid-schemas-accepted 75 to 74 (attgC044), valid-schemas-rejected held
at 0, no other bucket moved. The validation description broadened accordingly
(configuration pin updated).
Mihaela Mihaljevic
0f90b3a4d3