diff --git a/CHANGELOG.md b/CHANGELOG.md
index 586c8aa..7e72368 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
### Fixed
+- A `whiteSpace` facet may only strengthen, never relax, its base type's effective whiteSpace (XSD Part 2 §4.3.6, #170). The order is `preserve` < `replace` < `collapse`, so a base fixed to `collapse` admits only `collapse`, and a `replace` base admits `replace` or `collapse`. A derivation that relaxes it (for example `whiteSpace="replace"` over a `collapse` base, or restricting `xs:token` to `replace`) was accepted and is now rejected. The base's effective whiteSpace is its own facet, falling back to its built-in intrinsic; the check is atomic-only and, when a base type's own whiteSpace has not yet resolved, can only under-detect, never reject a valid restriction. XSTS: invalid schemas accepted 422 to 413, no other bucket raised.
- A top-level `xs:element` declaration may no longer carry `ref`, `form`, `minOccurs`, or `maxOccurs` (XSD 1.0 schema-for-schemas `topLevelElement`, #170). A global element is a declaration, never a particle or a reference, so those local-use attributes are invalid. The top-level-attribute applicability scan added earlier is generalized to cover both kinds; a local element particle inside a content model is unaffected. XSTS: invalid schemas accepted 424 to 422, no other bucket raised.
- An element `ref` may no longer carry `nillable`, `default`, `fixed`, `form`, or `block`, and an element or attribute `ref` may no longer have an inline type definition (XSD 1.0 `src-element.2.2`, #170). A reference is a use of a global declaration, not a declaration, so beyond `ref` it carries only `minOccurs`, `maxOccurs`, and `id`; the applicability check already excluded `name` and `type` from a `ref`, and this extends the exclusion to the remaining declaration-only properties. A `group`/`attributeGroup` ref and an attribute ref's `use`/`default`/`fixed` (which override on the use) are unaffected. XSTS: invalid schemas accepted 439 to 424, no other bucket raised. Disclosed under-detection: a `key`/`unique`/`keyref` child under a ref is not yet flagged.
- A top-level `xs:attribute` declaration may no longer carry `use`, `form`, or `ref` (XSD 1.0 schema-for-schemas `topLevelAttribute`, #170). Those belong to a local attribute use, not a global declaration; the per-component applicability table is the permissive global/local union and so could not draw the distinction, leaving such schemas accepted. A focused scan of the direct `attribute` children of `schema` (and of `redefine`) supplies the global-only constraint; a local attribute use inside a complex type or attribute group is unaffected. XSTS: invalid schemas accepted 454 to 439, no other bucket raised.
diff --git a/Sources/Schema/XSDSimpleParser.swift b/Sources/Schema/XSDSimpleParser.swift
index dd3c90e..3c9bc38 100644
--- a/Sources/Schema/XSDSimpleParser.swift
+++ b/Sources/Schema/XSDSimpleParser.swift
@@ -84,6 +84,45 @@ extension PureXML.Schema {
/// so an inherited facet is never flagged here.
static func facetDefinitionErrors(_ restriction: XSDTree, base: SimpleType) -> [String] {
countFacetErrors(restriction) + boundFacetErrors(restriction, base: base)
+ + whiteSpaceRestrictionErrors(restriction, base: base)
+ }
+
+ /// The `whiteSpace` facet may only strengthen, never relax, the base type's
+ /// effective whiteSpace (XSD Part 2 §4.3.6, the facet's valid-restriction
+ /// rule): the order is `preserve` < `replace` < `collapse`, so a base fixed
+ /// to `collapse` admits only `collapse`, and a base of `replace` admits
+ /// `replace` or `collapse`. Checked for an atomic base only; the base's
+ /// effective whiteSpace is its own facet, falling back to its built-in
+ /// intrinsic. If the base type has not resolved its own whiteSpace the check
+ /// can only under-detect, never reject a valid restriction.
+ private static func whiteSpaceRestrictionErrors(_ restriction: XSDTree, base: SimpleType) -> [String] {
+ guard case .atomic = base.variety, let declared = declaredWhiteSpace(restriction) else { return [] }
+ let baseWhiteSpace = base.facets.whiteSpace ?? base.base.whiteSpace
+ guard whiteSpaceStrength(declared) < whiteSpaceStrength(baseWhiteSpace) else { return [] }
+ return ["whiteSpace '\(whiteSpaceName(declared))' may not relax the base type's whiteSpace '\(whiteSpaceName(baseWhiteSpace))'"]
+ }
+
+ private static func declaredWhiteSpace(_ restriction: XSDTree) -> WhiteSpace? {
+ for facet in XSDNode.elementChildren(restriction) where XSDNode.localName(facet) == "whiteSpace" {
+ return whiteSpace(XSDNode.attribute(facet, "value"))
+ }
+ return nil
+ }
+
+ private static func whiteSpaceStrength(_ whiteSpace: WhiteSpace) -> Int {
+ switch whiteSpace {
+ case .preserve: 0
+ case .replace: 1
+ case .collapse: 2
+ }
+ }
+
+ private static func whiteSpaceName(_ whiteSpace: WhiteSpace) -> String {
+ switch whiteSpace {
+ case .preserve: "preserve"
+ case .replace: "replace"
+ case .collapse: "collapse"
+ }
}
/// Length-family findings: `length`, `minLength`, `maxLength`,
diff --git a/Tests/SchemaWhiteSpaceRestrictionTests.swift b/Tests/SchemaWhiteSpaceRestrictionTests.swift
new file mode 100644
index 0000000..23c4e75
--- /dev/null
+++ b/Tests/SchemaWhiteSpaceRestrictionTests.swift
@@ -0,0 +1,52 @@
+@testable import PureXML
+import Testing
+
+@Suite("XSD whiteSpace facet valid restriction (Part 2 §4.3.6)")
+struct SchemaWhiteSpaceRestrictionTests {
+ private let xsd = "xmlns:xs=\"http://www.w3.org/2001/XMLSchema\""
+
+ private func compiles(_ body: String) -> Bool {
+ (try? PureXML.Schema.Document("\(body)")) != nil
+ }
+
+ private func chain(_ baseWS: String, _ derivedWS: String) -> String {
+ ""
+ + ""
+ + ""
+ + ""
+ }
+
+ @Test("Relaxing the base whiteSpace is rejected")
+ func test_relaxRejected() {
+ #expect(!compiles(chain("collapse", "replace")))
+ #expect(!compiles(chain("collapse", "preserve")))
+ #expect(!compiles(chain("replace", "preserve")))
+ }
+
+ @Test("Keeping or strengthening the base whiteSpace compiles")
+ func test_strengthenAccepted() {
+ #expect(compiles(chain("collapse", "collapse")))
+ #expect(compiles(chain("replace", "collapse")))
+ #expect(compiles(chain("preserve", "collapse")))
+ #expect(compiles(chain("preserve", "replace")))
+ }
+
+ @Test("Relaxing a built-in's intrinsic whiteSpace is rejected")
+ func test_builtinIntrinsicRespected() {
+ // xs:token has intrinsic whiteSpace=collapse; a restriction may not relax it.
+ #expect(!compiles(
+ ""
+ + "",
+ ))
+ // Restating collapse on a token is fine.
+ #expect(compiles(
+ ""
+ + "",
+ ))
+ // Strengthening xs:string (preserve) to collapse is fine.
+ #expect(compiles(
+ ""
+ + "",
+ ))
+ }
+}
diff --git a/Tests/XSTSSuiteTests.swift b/Tests/XSTSSuiteTests.swift
index 50ca38d..0f102b1 100644
--- a/Tests/XSTSSuiteTests.swift
+++ b/Tests/XSTSSuiteTests.swift
@@ -29,7 +29,7 @@ struct XSTSSuiteTests {
/// XSTS` (debug is far slower and the corpus is large). Per-case deviations
/// are written to /tmp/xsts-failures.txt for the burn-down.
private let knownSchemaValidRejected = 1
- private let knownSchemaInvalidAccepted = 422
+ private let knownSchemaInvalidAccepted = 413
private let knownInstanceValidRejected = 180
private let knownInstanceInvalidAccepted = 158
diff --git a/docs/schema-validity-burndown.md b/docs/schema-validity-burndown.md
index 59b4b00..08d8c10 100644
--- a/docs/schema-validity-burndown.md
+++ b/docs/schema-validity-burndown.md
@@ -10,7 +10,7 @@ irreducible tail. Do not deviate to new features while this is open.
| Bucket | Count | Reading |
|---|---|---|
| valid-schemas-rejected | **72 -> 4** | production target is 0: rejecting a correct schema is the most user-hostile defect (#148). Particle-restriction over-rejection fixed: pointless `maxOccurs=0` particles removed, content-free restriction of an EMPTY base, empty-derived emptiable-base, and (#163) the pairwise check over the normalized content model with occurrence subsumption applied only to same-kind pairings (cross-kind element/group, group/element, group/wildcard match occurrence inside, by effective total range / member). #164 resolved element-ref namespaces by prefix binding (the `particlesJj/Jk/Jm/Jn/Js`, `particlesQ/R` cluster, -28). Content-free (`maxOccurs=0`) derived groups and substitution-group declaration order closed `particlesW006`/`elemZ027_a`; the W3C MapAndSum rule (Sequence:Choice, #165) closed `particlesV003`. Remaining 1 (`particlesZ001`): a documented spec ambiguity (RecurseAsIfGroup; the reference rejects it), not a defect. |
-| **invalid-schemas-accepted** | **2461 -> 422** | we rarely catch a bad one (facet, default/fixed value, particle-restriction name+type, id, structural content-model, UPA determinism, content order, identity-constraint XPath-subset, wildcard-namespace, final/block, simpleType content, group/wildcard and group/element cardinality, element-ref namespace, sequence/choice MapAndSum, circular type derivation, circular group/attributeGroup/substitution references, attribute-use uniqueness and single-ID, type-excludes-inline-type, ID-typed value-constraint exclusion, all-group reference placement, substitution-member type derivation, default/fixed mutual exclusion landed). |
+| **invalid-schemas-accepted** | **2461 -> 413** | we rarely catch a bad one (facet, default/fixed value, particle-restriction name+type, id, structural content-model, UPA determinism, content order, identity-constraint XPath-subset, wildcard-namespace, final/block, simpleType content, group/wildcard and group/element cardinality, element-ref namespace, sequence/choice MapAndSum, circular type derivation, circular group/attributeGroup/substitution references, attribute-use uniqueness and single-ID, type-excludes-inline-type, ID-typed value-constraint exclusion, all-group reference placement, substitution-member type derivation, default/fixed mutual exclusion landed). |
| valid-instances-rejected | **233 -> 180** | (instance side; #164's element-ref namespace fix is shared with instance validation, -34) |
| invalid-instances-accepted | **160 -> 158** | (instance side; resolving an inline `` restriction base preserves list/union variety, so a `length` facet counts items and two more invalid instances are caught) |