fix: empty inline nodes should not prevent margin collapse

float-pigment-forest/tests/custom/css_margin.rs

@@ -81,6 +81,19 @@ fn margin_collapse_1() {
     )
 }
 
+#[test]
+fn margin_collapse_empty_inline_nodes() {
+    assert_xml!(
+        r#"
+        <div style="height: 800px;">
+          <div style="height: 100px; margin-bottom: 50px;"></div>
+          <div style="display: inline; height: 0;"></div>
+          <div style="margin-top: 40px;" expect_top="150"></div>
+        </div>
+    "#
+    )
+}
+
 #[test]
 fn margin_collapse_negative() {
     assert_xml!(

float-pigment-layout/src/algo/flow.rs

@@ -674,17 +674,19 @@ impl<T: LayoutTreeNode> Flow<T> for LayoutUnit<T> {
                             request.kind == ComputeRequestKind::Position,
                         );
 
-                        if let Some((prev_collapsed_margin, prev_collapsed_through)) =
-                            prev_sibling_collapsed_margin
-                        {
-                            if !prev_collapsed_through {
-                                total_main_size += prev_collapsed_margin.solve();
+                        if block_size.main_size(axis_info.dir) > T::Length::zero() {
+                            if let Some((prev_collapsed_margin, prev_collapsed_through)) =
+                                prev_sibling_collapsed_margin
+                            {
+                                if !prev_collapsed_through {
+                                    total_main_size += prev_collapsed_margin.solve();
+                                }
                             }
+                            prev_sibling_collapsed_margin.replace((CollapsedMargin::zero(), false));
                         }
                         let main_offset = padding_border
                             .main_axis_start(axis_info.dir, axis_info.main_dir_rev)
                             + total_main_size;
-                        prev_sibling_collapsed_margin.replace((CollapsedMargin::zero(), false));
 
                         total_main_size += block_size.main_size(axis_info.dir);
                         max_cross_size = max_cross_size.max(block_size.cross_size(axis_info.dir));

rust-toolchain.toml

@@ -0,0 +1,4 @@
+[toolchain]
+channel = "1.81.0"
+components = [ "rustfmt", "clippy" ]
+profile = "minimal"