Mihaela Mihaljevic
90ae16cba1
Reject ambiguous content models at compile time via a Glushkov position
automaton over a literal, QName-resolved view of the raw schema tree, built
just for this rule and independent of the instance-validation content model.
The literal view resolves a ref's QName through the schema's prefix bindings
(not the blanket target namespace) and does not expand substitution groups,
removing the two false-overlap sources a check over the compiled model
produced. Determinism is per particle: a particle competing with a repetition
of itself is never a violation, so a fixed count {n,n} unrolls into copies in
sequence while a true range or unbounded repeat uses a self-loop, and only two
distinct source particles with overlapping labels conflict. The overlap test
is QName-only, an under-rejection that can never over-reject.
A position cap bounds pathological nesting (skipping the check, never
over-rejecting). The element-declarations-consistent test loses its
incidentally-ambiguous (a?, a) case in favor of a deterministic (a, b, a).
XSTS: invalid schemas accepted 884 to 864, valid schemas rejected held at 72,
instance buckets unchanged.
115 lines
4.6 KiB
Swift
115 lines
4.6 KiB
Swift
@testable import PureXML
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import Testing
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/// Unique Particle Attribution (cos-nonambig, XSD 1.0 3.8.6): a content model
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/// must be deterministic, so each element in an instance is attributable to a
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/// single particle without lookahead. The check runs on a literal, QName-resolved
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/// view of the raw schema tree (refs are not substitution-group expanded, the
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/// overlap test is QName-only), and is per particle: a particle competing with a
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/// repetition of itself is never a violation. These cases pin both the rejections
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/// and the deterministic shapes that must keep compiling (XSTS valid mgZ005,
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/// ctZ008, particlesHa142, groupH001).
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@Suite("Content model determinism (UPA)")
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struct ContentModelDeterminismTests {
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private func compile(_ body: String) throws {
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_ = try PureXML.Schema.Document("""
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<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
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\(body)
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</xs:schema>
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""")
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}
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private func rejects(_ body: String) -> Bool {
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do { try compile(body)
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return false
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} catch { return true }
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}
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private func complexType(_ model: String) -> String {
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#"<xs:complexType name="t">\#(model)</xs:complexType>"#
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}
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// MARK: - Ambiguous models are rejected
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@Test("a choice of two same-name elements is ambiguous")
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func test_choiceOfSameName() {
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#expect(rejects(complexType(#"<xs:choice><xs:element name="a"/><xs:element name="a"/></xs:choice>"#)))
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}
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@Test("an optional element followed by a same-name element is ambiguous")
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func test_optionalThenSameName() {
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#expect(rejects(complexType(#"<xs:sequence><xs:element name="a" minOccurs="0"/><xs:element name="a"/></xs:sequence>"#)))
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}
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@Test("a repeating element followed by a same-name element is ambiguous")
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func test_repeatThenSameName() {
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#expect(rejects(complexType(#"<xs:sequence><xs:element name="a" maxOccurs="unbounded"/><xs:element name="a"/></xs:sequence>"#)))
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}
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@Test("two same-name members of an all group are ambiguous")
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func test_allWithSameName() {
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#expect(rejects(complexType(#"<xs:all><xs:element name="a"/><xs:element name="a"/></xs:all>"#)))
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}
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@Test("an element competing with a wildcard that admits it is ambiguous")
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func test_elementAndWildcard() {
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#expect(rejects(complexType(#"<xs:choice><xs:element name="a"/><xs:any processContents="skip"/></xs:choice>"#)))
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}
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// MARK: - Deterministic models keep compiling
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@Test("distinct elements in sequence and choice are deterministic")
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func test_distinctNames() throws {
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try compile(complexType(#"<xs:sequence><xs:element name="a"/><xs:element name="b" minOccurs="0"/></xs:sequence>"#))
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try compile(complexType(#"<xs:choice><xs:element name="a"/><xs:element name="b"/></xs:choice>"#))
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try compile(complexType(#"<xs:all><xs:element name="a"/><xs:element name="b"/><xs:element name="c"/></xs:all>"#))
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}
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@Test("a fixed-count element followed by a distinct same-name element is deterministic (mgZ005)")
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func test_fixedCountThenSameName() throws {
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try compile(complexType(#"""
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<xs:sequence>
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<xs:element name="a" minOccurs="0"/>
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<xs:element name="b" minOccurs="2" maxOccurs="2"/>
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<xs:element name="b"/>
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</xs:sequence>
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"""#))
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}
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@Test("a fixed-count group wrapping a repeating element is deterministic (ctZ008)")
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func test_fixedCountGroupWithRepeat() throws {
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try compile(complexType(#"""
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<xs:sequence minOccurs="2" maxOccurs="2">
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<xs:element name="a" minOccurs="1" maxOccurs="2"/>
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<xs:element name="b" minOccurs="0"/>
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</xs:sequence>
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"""#))
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}
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@Test("an element followed by its own optional repeat is deterministic (particlesHa142)")
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func test_elementThenOptionalSameName() throws {
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try compile(complexType(#"""
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<xs:choice>
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<xs:sequence minOccurs="0">
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<xs:element name="a" type="xs:string"/>
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<xs:element name="a" type="xs:string" minOccurs="0"/>
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</xs:sequence>
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</xs:choice>
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"""#))
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}
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@Test("a bounded-repeat choice of group references is deterministic (groupH001)")
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func test_repeatedChoiceOfGroups() throws {
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try compile(#"""
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<xs:complexType name="A">
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<xs:choice minOccurs="0" maxOccurs="4">
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<xs:group ref="x"/>
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<xs:group ref="y"/>
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</xs:choice>
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</xs:complexType>
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<xs:group name="x"><xs:sequence><xs:element name="x1"/><xs:element name="x2"/></xs:sequence></xs:group>
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<xs:group name="y"><xs:choice><xs:element name="y1"/><xs:element name="y2"/></xs:choice></xs:group>
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"""#)
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}
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}
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