PureXML/Sources/Schema/XPathQueryCache.swift
Mihaela Mihaljevic ca56caf11c fix(schema): default/fixed value for identity-constraint fields; invalid-instances-accepted 50 to 45 (#147)
An identity-constraint (unique/key/keyref) field that selects an absent attribute
or an empty element whose declaration carries a default or fixed value now takes
that value as its identity-tuple component, so two members can collide on the
defaulted value (idG011/idG012 default, idF016/idF017 fixed) where the duplicate
was previously missed.

The default/fixed value constraints on identity-field targets are gathered at
compile time (identityFieldConstraints, mirroring identityFieldTypes) and threaded
through to the identity validator. The substitution is exact about absent versus
present-empty: an @attr field is defaulted only when the attribute is ABSENT (an
empty node-set), never when present with value ""; a "." element field only when
the selected element has no character content. Applying a default only adds an
identity value where the schema declares one, so it can create a genuine
duplicate-key detection but never reject a valid instance.

To keep within the file/type-size and one-type-per-file limits, FieldValue,
XPathQueryCache, and the schema-location hints were extracted to their own files
(behavior-preserving moves).

invalid-instances-accepted 50 to 45, no false positive (valid-instances-rejected
and valid-schemas-rejected held at 0), no other bucket moved. An adversarial
review probed present-empty attributes, element content winning over a default,
fixed values, keyref matching, multi-field keys, and merged-schema defaults, and
found no over-rejection.
2026-06-18 14:47:47 +02:00

14 lines
556 B
Swift

/// Compiles each distinct XPath string once per validation run, so a
/// constraint's selector and field queries are not re-parsed at every element
/// the walk visits. A string that fails to compile caches as nil (no match).
final class XPathQueryCache {
private var queries: [String: PureXML.XPath.Query?] = [:]
func query(_ xpath: String) -> PureXML.XPath.Query? {
if let cached = queries[xpath] { return cached }
let compiled = try? PureXML.XPath.Query(xpath)
queries[xpath] = compiled
return compiled
}
}