From dc3fc902f01b33f3ff67ce1afa850019b2bd8026 Mon Sep 17 00:00:00 2001
From: ldm0 <ldm2993593805@163.com>
Date: Mon, 19 Oct 2026 04:16:48 +0800
Subject: [PATCH] fix(layout): preserve wrapped flex distribution across
 overflow modes

Adopt the separate Taffy distribution fallback correction. Remove the scroll-only branch, preserve flex-start versus safe center behavior in every writing mode, and add a browser regression that checks child positions for visible and scroll overflow.

Validation: cargo fmt --all; cargo clippy --workspace --all-targets --all-features -- -D warnings; cargo nextest run --no-fail-fast (20287 passed, 18 skipped). The combined working tree passed these checks before this logical split. Frozen Release and focused browser/WPT validation also passed; final full WPT is running.

Original-commit: 4d5786f1a117aa804876925902a66c0d3125081a
---
 Cargo.lock                                 |  2 +-
 Cargo.toml                                 |  4 +--
 moli/tests/fetch_cli/layout_regressions.rs | 40 ++++++++++++++++++++++
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 22761832b8..52de8cefc9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5650,7 +5650,7 @@ dependencies = [
 [[package]]
 name = "taffy"
 version = "0.15.0"
-source = "git+https://github.com/ldm0/taffy?rev=9c9b9257de73437781df7facbd0aa7beac6abe3f#9c9b9257de73437781df7facbd0aa7beac6abe3f"
+source = "git+https://github.com/ldm0/taffy?rev=0a337871fa44db7d48571b06668f92737eefa8c2#0a337871fa44db7d48571b06668f92737eefa8c2"
 dependencies = [
  "serde",
  "slotmap",
diff --git a/Cargo.toml b/Cargo.toml
index e62ca4b7ef..ab6f8951cc 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -117,10 +117,10 @@ stylo_dom = { git = "https://github.com/lexmount/stylo", rev = "973988b9c592a802
 stylo_static_prefs = { git = "https://github.com/lexmount/stylo", rev = "973988b9c592a802eefdc5abe6072dd9ba221385" }
 stylo_traits = { git = "https://github.com/lexmount/stylo", rev = "973988b9c592a802eefdc5abe6072dd9ba221385" }
 svgtypes = { git = "https://github.com/lexmount/svgtypes", branch = "moli" }
-taffy = { git = "https://github.com/ldm0/taffy", rev = "9c9b9257de73437781df7facbd0aa7beac6abe3f" }
+taffy = { git = "https://github.com/ldm0/taffy", rev = "0a337871fa44db7d48571b06668f92737eefa8c2" }
 
 [patch."https://github.com/DioxusLabs/taffy"]
-taffy = { git = "https://github.com/ldm0/taffy", rev = "9c9b9257de73437781df7facbd0aa7beac6abe3f" }
+taffy = { git = "https://github.com/ldm0/taffy", rev = "0a337871fa44db7d48571b06668f92737eefa8c2" }
 
 [workspace.lints.clippy]
 disallowed_methods = "deny"
diff --git a/moli/tests/fetch_cli/layout_regressions.rs b/moli/tests/fetch_cli/layout_regressions.rs
index 969a78ad8b..f59afec7b7 100644
--- a/moli/tests/fetch_cli/layout_regressions.rs
+++ b/moli/tests/fetch_cli/layout_regressions.rs
@@ -261,3 +261,43 @@ fn wrapped_vertical_flex_keeps_padding_in_its_scroll_extent() -> Result<()> {
     }
     Ok(())
 }
+
+#[test]
+fn wrapped_flex_distribution_keeps_child_positions_for_visible_and_scroll_overflow() -> Result<()> {
+    let mut body = String::from("<!doctype html><body>");
+    for (mode, direction, flow) in [
+        ("horizontal-tb", "ltr", "row"),
+        ("vertical-rl", "rtl", "column"),
+    ] {
+        for overflow in ["visible", "scroll"] {
+            for align in ["stretch", "space-between", "space-around", "space-evenly"] {
+                body.push_str(&format!("<div id='flex-{mode}-{overflow}-{align}' data-flex-probe style='display:flex;writing-mode:{mode};direction:{direction};flex-flow:{flow} wrap-reverse;width:100px;height:100px;overflow:{overflow};border:3px solid;padding:10px;gap:10px;align-items:start;align-content:{align};margin-top:300px'>"));
+                for _ in 0..3 {
+                    body.push_str("<div style='min-width:110px;min-height:110px'></div>");
+                }
+                body.push_str("</div>");
+            }
+        }
+    }
+    let expression = r#"JSON.stringify(Object.fromEntries([...document.querySelectorAll('[data-flex-probe]')].map(e => {const top=e.getBoundingClientRect().top;return [e.id,Object.fromEntries([...e.children].map((child,i)=>['y'+i,child.getBoundingClientRect().top-top]))]})))"#;
+    let value = run_layout(&body, expression, false)?;
+    for mode in ["horizontal-tb", "vertical-rl"] {
+        for overflow in ["visible", "scroll"] {
+            for align in ["stretch", "space-between", "space-around", "space-evenly"] {
+                // Fixed Chromium control values distinguish flex-start fallback from
+                // safe center, including the opposite cross flow of vertical RTL.
+                let expected = match (mode, align) {
+                    ("horizontal-tb", "stretch" | "space-between") => [3.0, -117.0, -237.0],
+                    ("horizontal-tb", _) => [253.0, 133.0, 13.0],
+                    (_, "stretch" | "space-between") => [13.0, 133.0, 253.0],
+                    _ => [-237.0, -117.0, 3.0],
+                };
+                let id = format!("flex-{mode}-{overflow}-{align}");
+                for (index, y) in expected.into_iter().enumerate() {
+                    assert_dimension(&value, &id, &format!("y{index}"), y);
+                }
+            }
+        }
+    }
+    Ok(())
+}