LibWeb: Treat CSS selectors containing undeclared namespaces as invalid

Selectors containing undeclared namespaces should be considered invalid,
not just not matching any elements.

Gains us 3 new WPT passes.

Libraries/LibWeb/CSS/CSSGroupingRule.cpp

@@ -47,7 +47,7 @@ WebIDL::ExceptionOr<u32> CSSGroupingRule::insert_rule(StringView rule, u32 index
 {
     // The insertRule(rule, index) method must return the result of invoking insert a CSS rule rule into the child CSS
     // rules at index, with the nested flag set.
-    TRY(m_rules->insert_a_css_rule(rule, index, CSSRuleList::Nested::Yes));
+    TRY(m_rules->insert_a_css_rule(rule, index, CSSRuleList::Nested::Yes, m_parent_style_sheet->declared_namespaces()));
 
     // AD-HOC: The spec doesn't say where to set the parent rule, so we'll do it here.
     m_rules->item(index)->set_parent_rule(this);

Libraries/LibWeb/CSS/CSSRuleList.cpp

@@ -49,8 +49,9 @@ void CSSRuleList::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_owner_rule);
 }
 
+// AD-HOC: The spec doesn't include a declared_namespaces parameter, but we need it to handle parsing of namespaced selectors.
 // https://drafts.csswg.org/cssom/#insert-a-css-rule
-WebIDL::ExceptionOr<unsigned> CSSRuleList::insert_a_css_rule(Variant<StringView, CSSRule*> rule, u32 index, Nested nested)
+WebIDL::ExceptionOr<unsigned> CSSRuleList::insert_a_css_rule(Variant<StringView, CSSRule*> rule, u32 index, Nested nested, HashTable<FlyString> const& declared_namespaces)
 {
     // 1. Set length to the number of items in list.
     auto length = m_rules.size();
@@ -63,9 +64,13 @@ WebIDL::ExceptionOr<unsigned> CSSRuleList::insert_a_css_rule(Variant<StringView,
     // NOTE: The insert-a-css-rule spec expects `rule` to be a string, but the CSSStyleSheet.insertRule()
     //       spec calls this algorithm with an already-parsed CSSRule. So, we use a Variant and skip step 3
     //       if that variant holds a CSSRule already.
+
     CSSRule* new_rule = nullptr;
     if (rule.has<StringView>()) {
-        new_rule = parse_css_rule(Parser::ParsingParams { realm() }, rule.get<StringView>());
+        Parser::ParsingParams parsing_params { realm() };
+        parsing_params.declared_namespaces = declared_namespaces;
+
+        new_rule = parse_css_rule(parsing_params, rule.get<StringView>());
     } else {
         new_rule = rule.get<CSSRule*>();
     }
@@ -74,6 +79,8 @@ WebIDL::ExceptionOr<unsigned> CSSRuleList::insert_a_css_rule(Variant<StringView,
     if (!new_rule && nested == Nested::Yes) {
         Parser::ParsingParams parsing_params { realm() };
         parsing_params.rule_context = rule_context();
+        parsing_params.declared_namespaces = declared_namespaces;
+
         // - Set declarations to the results of performing parse a CSS declaration block, on argument rule.
         auto declarations = parse_css_property_declaration_block(parsing_params, rule.get<StringView>());
 

Libraries/LibWeb/CSS/CSSRuleList.h

@@ -57,7 +57,7 @@ public:
         No,
         Yes,
     };
-    WebIDL::ExceptionOr<unsigned> insert_a_css_rule(Variant<StringView, CSSRule*>, u32 index, Nested = Nested::No);
+    WebIDL::ExceptionOr<unsigned> insert_a_css_rule(Variant<StringView, CSSRule*>, u32 index, Nested, HashTable<FlyString> const& declared_namespaces);
 
     void for_each_effective_rule(TraversalOrder, Function<void(CSSRule const&)> const& callback) const;
     // Returns whether the match state of any media queries changed after evaluation.

Libraries/LibWeb/CSS/CSSStyleRule.cpp

@@ -126,12 +126,17 @@ void CSSStyleRule::set_selector_text(StringView selector_text)
     clear_caches();
 
     // 1. Run the parse a group of selectors algorithm on the given value.
+    Parser::ParsingParams parsing_params { realm() };
+
+    if (m_parent_style_sheet)
+        parsing_params.declared_namespaces = m_parent_style_sheet->declared_namespaces();
+
     Optional<SelectorList> parsed_selectors;
     if (parent_style_rule()) {
         // AD-HOC: If we're a nested style rule, then we need to parse the selector as relative and then adapt it with implicit &s.
-        parsed_selectors = parse_selector_for_nested_style_rule(Parser::ParsingParams { realm() }, selector_text);
+        parsed_selectors = parse_selector_for_nested_style_rule(parsing_params, selector_text);
     } else {
-        parsed_selectors = parse_selector(Parser::ParsingParams { realm() }, selector_text);
+        parsed_selectors = parse_selector(parsing_params, selector_text);
     }
 
     // 2. If the algorithm returns a non-null value replace the associated group of selectors with the returned value.

Libraries/LibWeb/CSS/CSSStyleSheet.cpp

@@ -151,7 +151,7 @@ WebIDL::ExceptionOr<unsigned> CSSStyleSheet::insert_rule(StringView rule, unsign
         return WebIDL::SyntaxError::create(realm(), "Can't insert @import rules into a constructed stylesheet."_string);
 
     // 6. Return the result of invoking insert a CSS rule rule in the CSS rules at index.
-    auto result = m_rules->insert_a_css_rule(parsed_rule, index);
+    auto result = m_rules->insert_a_css_rule(parsed_rule, index, CSSRuleList::Nested::No, declared_namespaces());
 
     if (!result.is_exception()) {
         // NOTE: The spec doesn't say where to set the parent style sheet, so we'll do it here.
@@ -375,6 +375,17 @@ Optional<FlyString> CSSStyleSheet::default_namespace() const
     return {};
 }
 
+HashTable<FlyString> CSSStyleSheet::declared_namespaces() const
+{
+    HashTable<FlyString> declared_namespaces;
+
+    for (auto namespace_ : m_namespace_rules.keys()) {
+        declared_namespaces.set(namespace_);
+    }
+
+    return declared_namespaces;
+}
+
 Optional<FlyString> CSSStyleSheet::namespace_uri(StringView namespace_prefix) const
 {
     return m_namespace_rules.get(namespace_prefix)
@@ -444,9 +455,14 @@ bool CSSStyleSheet::has_associated_font_loader(FontLoader& font_loader) const
 
 Parser::ParsingParams CSSStyleSheet::make_parsing_params() const
 {
+    Parser::ParsingParams parsing_params;
     if (auto document = owning_document())
-        return Parser::ParsingParams { *document };
-    return Parser::ParsingParams { realm() };
+        parsing_params = Parser::ParsingParams { *document };
+    else
+        parsing_params = Parser::ParsingParams { realm() };
+
+    parsing_params.declared_namespaces = declared_namespaces();
+    return parsing_params;
 }
 
 }

Libraries/LibWeb/CSS/CSSStyleSheet.h

@@ -72,6 +72,7 @@ public:
 
     Optional<FlyString> default_namespace() const;
     GC::Ptr<CSSNamespaceRule> default_namespace_rule() const { return m_default_namespace_rule; }
+    HashTable<FlyString> declared_namespaces() const;
 
     Optional<FlyString> namespace_uri(StringView namespace_prefix) const;
 

Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -66,6 +66,7 @@ Parser::Parser(ParsingParams const& context, Vector<Token> tokens)
     , m_tokens(move(tokens))
     , m_token_stream(m_tokens)
     , m_rule_context(move(context.rule_context))
+    , m_declared_namespaces(move(context.declared_namespaces))
 {
 }
 
@@ -141,6 +142,8 @@ GC::RootVector<GC::Ref<CSSRule>> Parser::convert_rules(Vector<Rule> const& raw_r
 
             if (!namespace_rules_valid)
                 continue;
+
+            m_declared_namespaces.set(as<CSSNamespaceRule>(*rule).prefix());
             break;
         default:
             import_rules_valid = false;

Libraries/LibWeb/CSS/Parser/Parser.h

@@ -81,6 +81,7 @@ struct ParsingParams {
     ParsingMode mode { ParsingMode::Normal };
 
     Vector<RuleContext> rule_context;
+    HashTable<FlyString> declared_namespaces;
 };
 
 // The very large CSS Parser implementation code is broken up among several .cpp files:
@@ -543,6 +544,7 @@ private:
     bool context_allows_quirky_length() const;
 
     Vector<RuleContext> m_rule_context;
+    HashTable<FlyString> m_declared_namespaces;
 
     Vector<PseudoClass> m_pseudo_class_context; // Stack of pseudo-class functions we're currently inside
 };

Libraries/LibWeb/CSS/Parser/SelectorParsing.cpp

@@ -258,8 +258,10 @@ Optional<Selector::SimpleSelector::QualifiedName> Parser::parse_selector_qualifi
             ? Selector::SimpleSelector::QualifiedName::NamespaceType::Any
             : Selector::SimpleSelector::QualifiedName::NamespaceType::Named;
 
-        // FIXME: https://www.w3.org/TR/selectors-4/#invalid
-        //        - a simple selector containing an undeclared namespace prefix is invalid
+        // https://www.w3.org/TR/selectors-4/#invalid
+        // a simple selector containing an undeclared namespace prefix is invalid
+        if (namespace_type == Selector::SimpleSelector::QualifiedName::NamespaceType::Named && !m_declared_namespaces.contains(namespace_))
+            return {};
 
         transaction.commit();
         return Selector::SimpleSelector::QualifiedName {

Tests/LibWeb/Ref/expected/wpt-import/css/css-namespaces/reference/ref-lime-1.xml

@@ -0,0 +1,10 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <link rel="author" title="L. David Baron" href="https://dbaron.org/"/>
+  <link rel="author" title="Mozilla" href="http://mozilla.org/"/>
+  <title>CSS Namespaces Test Suite reference</title>
+ </head>
+ <body>
+  <p><test style="background: lime">This sentence should have a green background.</test></p>
+ </body>
+</html>

Tests/LibWeb/Ref/input/wpt-import/css/css-conditional/at-supports-045.html

@@ -0,0 +1,38 @@
+<!doctype html>
+<head>
+	<title>CSS Test (Conditional Rules): Invalid rules after @supports</title>
+	<!-- This test is paired with at-media-003.html ; please keep them in sync -->
+	<link rel="author" title="Elika J. Etemad" href="http://fantasai.inkedblade.net/contact">
+	<link rel="help" href="https://www.w3.org/TR/css-conditional-3/#contents-of">
+	<link rel="match" href="../../../../expected/wpt-import/css/css-conditional/at-supports-001-ref.html">
+	<meta name="assert"
+	      content="Test passes if rules required to occur before all style rules are invalid after @supports.">
+	<style>
+		@namespace x "http://www.w3.org/";
+		@supports (background: blue) { /* invalidates later rules even if empty */ }
+		@import "support/fail.css";
+		@namespace y "http://www.w3.org/";
+
+		.test1, x|div { background: green; }
+		.test1, y|div { background: red; }
+
+		div {
+			background: red;
+			height: 50px;
+			width: 100px;
+		}
+	</style>
+	<style>
+		@supports (background: blue) {
+			/* @supports isn't invalidated, only misordered stuff after it is */
+			.test2 { background: green; }
+		}
+		@import "support/fail.css";
+	</style>
+</head>
+<body>
+	<p>Test passes if there is a <strong>filled green square</strong> and <strong>no red</strong>.</p>
+	<div class="test1"></div>
+	<div class="test2"></div>
+</body>
+</html>

Tests/LibWeb/Ref/input/wpt-import/css/css-conditional/support/fail.css

@@ -0,0 +1 @@
+* { background:red ! important }

Tests/LibWeb/Ref/input/wpt-import/css/css-namespaces/scope-002.xml

@@ -0,0 +1,21 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <link rel="author" title="Anne van Kesteren" href="http://annevankesteren.nl/"/>
+  <link rel="author" title="Opera Software ASA" href="http://opera.com/"/>
+  <link rel="help" href="http://www.w3.org/TR/css-namespaces-3/#scope"/>
+  <link rel="match" href="../../../../expected/wpt-import/css/css-namespaces/reference/ref-lime-1.xml"/>
+  <title>CSS Namespaces Test Suite: scope @import</title>
+  <style>
+   test { background:lime }
+  </style>
+  <style>
+   @import url("support/scope-002a.css");
+   @import url("support/scope-002b.css");
+   @namespace w "test";
+   x|test { background:red }
+  </style>
+ </head>
+ <body>
+  <p><test xmlns="test">This sentence should have a green background.</test></p>
+ </body>
+</html>

Tests/LibWeb/Ref/input/wpt-import/css/css-namespaces/support/scope-002a.css

@@ -0,0 +1,3 @@
+@namespace x url("test");
+@namespace y url("test");
+w|test { background:red }

Tests/LibWeb/Ref/input/wpt-import/css/css-namespaces/support/scope-002b.css

@@ -0,0 +1,2 @@
+y|test { background: red }
+

Tests/LibWeb/Text/expected/wpt-import/css/cssom/at-namespace.txt

@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Pass
+Pass	CSS Test: @namespace in CSSOM is not severely broken

Tests/LibWeb/Text/input/wpt-import/css/cssom/at-namespace.html

@@ -0,0 +1,29 @@
+<!doctype html>
+<title>CSS Test: @namespace in CSSOM is not severely broken</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1464865">
+<link rel="help" href="https://drafts.csswg.org/cssom/#insert-a-css-rule">
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<style id="s">
+  div { color: green }
+</style>
+<div>Should be green</div>
+<script>
+test(function() {
+  assert_throws_dom("InvalidStateError", function() {
+    s.sheet.insertRule('@namespace myhtml url("http://www.w3.org/1999/xhtml")', 0);
+  });
+  assert_equals(s.sheet.cssRules.length, 1, "Shouldn't have been inserted");
+  assert_throws_dom("SyntaxError", function() {
+    s.sheet.insertRule("myhtml|div { color: red !important }", 0);
+  });
+  assert_equals(s.sheet.cssRules.length, 1);
+  assert_equals(
+    getComputedStyle(document.querySelector("div")).color,
+    "rgb(0, 128, 0)",
+    "Namespace shouldn't be registered"
+  );
+});
+</script>
+