Batch fix: svg: a selector's class checks count against the CSS matching budget (#2159)

crates/svg/src/lib.rs

@@ -635,14 +635,16 @@ impl<'a, 'i> Parser<'a, 'i> {
         if !self.charge_css(buckets.iter().map(|b| b.len()).fold(0, usize::saturating_add)) {
             return;
         }
-        let mut matching: Vec<&Rule> = buckets
-            .iter()
-            .flat_map(|b| b.iter())
-            .filter_map(|&i| css.rules.get(i))
+        let candidates = || buckets.iter().flat_map(|b| b.iter()).filter_map(|&i| css.rules.get(i));
+        // A selector like `.z.z.z…` checks each of its classes: charge them too.
+        if !self.charge_css(candidates().map(|r| r.classes.len()).fold(0, usize::saturating_add)) {
+            return;
+        }
+        let mut matching: Vec<&Rule> = candidates()
             .filter(|r| {
                 r.tag.as_deref().is_none_or(|t| t == tag)
                     && r.id.as_deref().is_none_or(|i| Some(i) == id)
-                    && r.classes.iter().all(|c| classes.contains(&c.as_str()))
+                    && r.classes.iter().all(|c| classes.binary_search(&c.as_str()).is_ok())
             })
             .collect();
         matching.sort_by_key(|r| (r.specificity, r.order));

crates/svg/src/tests.rs

@@ -379,6 +379,22 @@ fn huge_class_lists_count_against_the_matching_budget() {
     assert!(parse(svg(&few).as_bytes()).is_ok());
 }
 
+#[test]
+fn a_selector_with_many_classes_counts_against_the_matching_budget() {
+    // `.z.z.z…` lands in one class bucket, but each match checks every class it lists.
+    let rule = ".z".repeat(300_000);
+    let uses: String = (0..200).map(|i| format!(r##"<use href="#r" x="{i}"/>"##)).collect();
+    let svg = |uses: &str| {
+        format!(
+            r##"<svg xmlns="http://www.w3.org/2000/svg" width="10" height="10"><style>{rule}{{fill:red}}</style><defs><rect id="r" width="1" height="1" class="z"/></defs>{uses}</svg>"##
+        )
+    };
+    let e = parse(svg(&uses).as_bytes()).unwrap_err();
+    assert!(e.to_string().contains("<style> rules"), "{e}");
+    let few: String = uses.split_inclusive("/>").take(10).collect();
+    assert!(parse(svg(&few).as_bytes()).is_ok());
+}
+
 #[test]
 fn matching_work_past_the_budget_errors_without_doing_it() {
     // Within both sheet caps, yet one rectangle would apply 10 000 x 5 001 declarations.