LibWeb: Treat import rules as invalid if preceded by non-import rules

If an import statement is preceded by a valid rule that isn't an import rule or a @layer statement rule, it is now treated as invalid.
tcl3 · Jan 16, 2025 · a1516d0 · a1516d0
1 parent d7ff409
commit a1516d0
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diff --git a/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -17,6 +17,8 @@
 #include <AK/GenericLexer.h>
 #include <AK/SourceLocation.h>
 #include <AK/TemporaryChange.h>
+#include <LibWeb/CSS/CSSImportRule.h>
+#include <LibWeb/CSS/CSSLayerStatementRule.h>
 #include <LibWeb/CSS/CSSStyleDeclaration.h>
 #include <LibWeb/CSS/CSSStyleSheet.h>
 #include <LibWeb/CSS/CSSStyleValue.h>
@@ -161,6 +163,7 @@ CSSStyleSheet* Parser::parse_as_css_stylesheet(Optional<URL::URL> location)
 
     // Interpret all of the resulting top-level qualified rules as style rules, defined below.
     GC::RootVector<CSSRule*> rules(m_context.realm().heap());
+    auto more_import_rules_allowed = true;
     for (auto const& raw_rule : style_sheet.rules) {
         auto rule = convert_to_rule(raw_rule, Nested::No);
         // If any style rule is invalid, or any at-rule is not recognized or is invalid according to its grammar or context, it’s a parse error.
@@ -169,6 +172,18 @@ CSSStyleSheet* Parser::parse_as_css_stylesheet(Optional<URL::URL> location)
             log_parse_error();
             continue;
         }
+        // https://drafts.csswg.org/css-cascade-5/#at-import
+        // Any @import rules must precede all other valid at-rules and style rules in a style sheet (ignoring @charset and @layer statement rules)
+        // and must not have any other valid at-rules or style rules between it and previous @import rules, or else the @import rule is invalid.
+        auto is_layer_statement_rule = is<CSSLayerStatementRule>(*rule);
+        auto is_import_rule = is<CSSImportRule>(*rule);
+
+        // FIXME: Include @charset rules in this check when they are added.
+        if (!(is_layer_statement_rule || is_import_rule)) {
+            more_import_rules_allowed = false;
+        } else if (is_import_rule && !more_import_rules_allowed) {
+            continue;
+        }
         rules.append(rule);
     }
 

diff --git a/Tests/LibWeb/Ref/expected/wpt-import/css/CSS2/css1/c11-import-000-ref.xht b/Tests/LibWeb/Ref/expected/wpt-import/css/CSS2/css1/c11-import-000-ref.xht
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+
+<html xmlns="http://www.w3.org/1999/xhtml">
+
+ <head>
+
+  <title>CSS Reftest Reference</title>
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" />
+
+  <style type="text/css"><![CDATA[
+  p {color: green;}
+  ]]></style>
+
+ </head>
+
+ <body>
+
+  <p>This text should be green.</p>
+
+  <p>This text should be green.</p>
+
+  <p>This text should be green.</p>
+
+  <p>This text should be green.</p>
+
+ </body>
+</html>
diff --git a/Tests/LibWeb/Ref/input/wpt-import/css/CSS2/css1/c11-import-000.xht b/Tests/LibWeb/Ref/input/wpt-import/css/CSS2/css1/c11-import-000.xht
@@ -0,0 +1,29 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Basic Containment</title>
+  <link rel="help" href="http://www.w3.org/TR/REC-CSS1#containment-in-html"/>
+  <link rel="author" title="CSS1 Test Suite Contributors" href="http://www.w3.org/Style/CSS/Test/CSS1/current/tsack.html"/>
+  <link rel="author" title="Ian Hickson" href="mailto:[email protected]"/>
+  <style type="text/css"><![CDATA[
+   @import url(support/a-green.css);
+   @import "support/b-green.css";
+   .c { color: green; }
+   @import url(support/c-red.css);
+   <!-- .d { color: green; } -->
+  ]]></style>
+  <link rel="help" href="http://www.w3.org/TR/CSS21/cascade.html#at-import" title="6.3 The @import rule"/>
+  <link rel="help" href="http://www.w3.org/TR/css-cascade-3/#at-import"/>
+  <link rel="help" href="http://www.w3.org/TR/css-cascade-4/#at-import"/>
+  <link rel="help" href="http://www.w3.org/TR/CSS21/syndata.html#comments" title="4.1.9 Comments"/>
+  <link rel="help" href="http://www.w3.org/TR/CSS21/syndata.html#uri" title="4.3.4 URLs and URIs"/>
+  <link rel="match" href="../../../../../expected/wpt-import/css/CSS2/css1/c11-import-000-ref.xht" />
+
+ </head>
+ <body>
+  <p class="a">This text should be green.</p>
+  <p class="b">This text should be green.</p>
+  <p class="c">This text should be green.</p>
+  <p class="d">This text should be green.</p>
+ </body>
+</html>
diff --git a/Tests/LibWeb/Ref/input/wpt-import/css/CSS2/css1/support/a-green.css b/Tests/LibWeb/Ref/input/wpt-import/css/CSS2/css1/support/a-green.css
@@ -0,0 +1 @@
+.a { color: green; }
diff --git a/Tests/LibWeb/Ref/input/wpt-import/css/CSS2/css1/support/b-green.css b/Tests/LibWeb/Ref/input/wpt-import/css/CSS2/css1/support/b-green.css
@@ -0,0 +1 @@
+.b { color: green; }
diff --git a/Tests/LibWeb/Ref/input/wpt-import/css/CSS2/css1/support/c-red.css b/Tests/LibWeb/Ref/input/wpt-import/css/CSS2/css1/support/c-red.css
@@ -0,0 +1 @@
+.c { color: red; }