From f62ce2604ede65a9400441c3e959d2855a7d5ad7 Mon Sep 17 00:00:00 2001
From: SGavrl <277843151+SGavrl@users.noreply.github.com>
Date: Fri, 31 Jul 2026 04:04:44 +0000
Subject: [PATCH] Contain definite floats through clearfix bands

---
 crates/obscura-render/src/dom.rs           | 22 +++++++++++---
 crates/obscura-render/tests/layout_test.rs | 34 ++++++++++++++++++++++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/crates/obscura-render/src/dom.rs b/crates/obscura-render/src/dom.rs
index b01d0bb..c7a13fe 100644
--- a/crates/obscura-render/src/dom.rs
+++ b/crates/obscura-render/src/dom.rs
@@ -7952,7 +7952,13 @@ fn build_children_with_float_zone(
             crate::Dimension::Px(_) | crate::Dimension::Percent(_)
         ) && parent.size_expressions[1].is_none()
     });
-    if parent_has_definite_height {
+    let parent_has_clearfix = styles.get(&parent_id).is_some_and(|parent| {
+        parent.after_pseudo.as_deref().is_some_and(|after| {
+            matches!(after.clear, Some(crate::Clear::Left | crate::Clear::Both))
+                && has_in_flow_generated_pseudo(Some(after))
+        })
+    });
+    if parent_has_definite_height || parent_has_clearfix {
         let fills_axis = |value: f32| (value - 1.0).abs() < 0.001;
         let substantive: Vec<NodeId> = dom_children
             .iter()
@@ -7979,10 +7985,14 @@ fn build_children_with_float_zone(
                 matches!(style.height, crate::Dimension::Percent(value) if fills_axis(value))
                     && style.size_expressions[1].is_none()
             });
+            let float_has_definite_height = float_style.is_some_and(|style| {
+                matches!(style.height, crate::Dimension::Px(_)) && style.size_expressions[1].is_none()
+            }) || float_fills_height;
             let sole_full_width_float = substantive.len() == 1
                 && float_percent_width.is_some_and(fills_axis)
-                && float_fills_height;
-            let split_band_flow = if substantive.len() == 2
+                && float_has_definite_height;
+            let split_band_flow = if parent_has_definite_height
+                && substantive.len() == 2
                 && substantive[0] == float_dom
                 && float_style.and_then(|style| style.float) == Some(crate::Float::Left)
                 && float_fills_height
@@ -8053,7 +8063,11 @@ fn build_children_with_float_zone(
                             align_items: Some(taffy::AlignItems::FLEX_START),
                             size: taffy::Size {
                                 width: taffy::Dimension::percent(1.0),
-                                height: taffy::Dimension::percent(1.0),
+                                height: if parent_has_definite_height {
+                                    taffy::Dimension::percent(1.0)
+                                } else {
+                                    taffy::Dimension::auto()
+                                },
                             },
                             ..Default::default()
                         };
diff --git a/crates/obscura-render/tests/layout_test.rs b/crates/obscura-render/tests/layout_test.rs
index 064d17e..3bbd004 100644
--- a/crates/obscura-render/tests/layout_test.rs
+++ b/crates/obscura-render/tests/layout_test.rs
@@ -944,6 +944,40 @@ fn full_width_percentage_float_uses_definite_containing_block() {
     );
 }
 
+#[test]
+fn clearfix_contains_a_full_width_definite_height_float() {
+    let tree = parse_html(
+        r#"
+        <style>
+          html, body { margin: 0 }
+          #host { width: 100% }
+          #host::before, #host::after { content: " "; display: table }
+          #host::after { clear: both }
+          #float { float: left; width: 100%; height: 600px }
+        </style>
+        <div id="host"><div id="float"></div></div>
+        "#,
+    );
+    let layout = layout_dom(&tree, (800.0, 700.0));
+    let rect = |id| layout.rects[&tree.get_element_by_id(id).unwrap()];
+    let host = rect("host");
+    let float = rect("float");
+    assert!(
+        (host.x - 0.0).abs() < 0.01
+            && (host.y - 0.0).abs() < 0.01
+            && (host.width - 800.0).abs() < 0.01
+            && (host.height - 600.0).abs() < 0.01,
+        "host: {host:?}"
+    );
+    assert!(
+        (float.x - 0.0).abs() < 0.01
+            && (float.y - 0.0).abs() < 0.01
+            && (float.width - 800.0).abs() < 0.01
+            && (float.height - 600.0).abs() < 0.01,
+        "float: {float:?}"
+    );
+}
+
 #[test]
 fn percentage_float_and_inline_sibling_share_definite_height_band() {
     let tree = parse_html(