Add stacking context damage when outline-width becomes non-zero (#274)

Loirooriol · mrobinson · web-flow · commit ae78004b3056 · 2025-11-27T12:49:18.000Z
As an optimization, we skip outlines in the stacking context if they
have a width of zero. This means that when it becomes non-zero, we need
stacking context damage.

Signed-off-by: Oriol Brufau &lt;obrufau@igalia.com&gt;
Co-authored-by: Martin Robinson &lt;mrobinson@igalia.com&gt;
diff --git a/style/servo/restyle_damage.rs b/style/servo/restyle_damage.rs
@@ -19,6 +19,7 @@ use crate::properties::{
 use crate::values::computed::basic_shape::ClipPath;
 use crate::values::computed::Perspective;
 use crate::values::generics::transform::{GenericRotate, GenericScale, GenericTranslate};
+use crate::Zero;
 use std::fmt;
 
 bitflags! {
@@ -148,6 +149,7 @@ fn augmented_restyle_damage_rebuild_stacking_context(
 ) -> bool {
     restyle_damage_rebuild_stacking_context(old, new)
         || old.guarantees_stacking_context() != new.guarantees_stacking_context()
+        || old.get_outline().outline_width.is_zero() != new.get_outline().outline_width.is_zero()
 }
 fn compute_damage(old: &ComputedValues, new: &ComputedValues) -> ServoRestyleDamage {
     let mut damage = ServoRestyleDamage::empty();
