Fix explicit height edge case with absolute / relative nested divs.

Needed for #6643.
servo · bors-servo · Aug 11, 2015 · Aug 11, 2015 · Aug 11, 2015 · e83091d918d55818d41edc4ba93e1ca9f0622bce
commit e83091d918d55818d41edc4ba93e1ca9f0622bce
diff --git a/components/layout/block.rs b/components/layout/block.rs
@@ -1104,7 +1104,8 @@ impl BlockFlow {
             let screen_size = LogicalSize::from_physical(self.fragment.style.writing_mode,
                                                          layout_context.shared.screen_size);
             Some(screen_size.block)
-        } else if self.base.flags.contains(IS_ABSOLUTELY_POSITIONED) {
+        } else if self.base.flags.contains(IS_ABSOLUTELY_POSITIONED) &&
+                  self.base.block_container_explicit_block_size.is_none() {
             self.base.absolute_cb.explicit_block_containing_size(layout_context)
         } else {
             self.base.block_container_explicit_block_size
@@ -1329,12 +1330,7 @@ impl BlockFlow {
 
         let mut iterator = self.base.child_iter().enumerate().peekable();
         while let Some((i, kid)) = iterator.next() {
-            {
-                let kid_base = flow::mut_base(kid);
-                if !kid_base.flags.contains(IS_ABSOLUTELY_POSITIONED) {
-                    kid_base.block_container_explicit_block_size = explicit_content_size;
-                }
-            }
+            flow::mut_base(kid).block_container_explicit_block_size = explicit_content_size;
 
             // Determine float impaction, and update the inline size speculations if necessary.
             if flow::base(kid).flags.contains(CLEARS_LEFT) {

diff --git a/tests/ref/abs_rel_explicit_height.html b/tests/ref/abs_rel_explicit_height.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+    <html>
+        <head>
+            <style type="text/css">
+                * {
+                    margin: 0;
+                }
+                html, body {
+                    position: relative;
+                    height: 100%;
+                }
+                #div0 {
+                    position: absolute;
+                    height: 100%;
+                    width: 100%;
+                }
+                #div1 {
+                    position: relative;
+                    height: 100px;
+                }
+                #div2 {
+                    position: absolute;
+                    width: 100%;
+                    height: 100%;
+                }
+                #div3 {
+                    position: relative;
+                    width: 100%;
+                    height: 100%;
+                }
+                #div4 {
+                    position: absolute;
+                    width: 100%;
+                    height: 100%;
+                    background-color: green;
+                }
+            </style>
+        </head>
+    <body>
+        <div id="div0">
+            <div id="div1">
+                <div id="div2">
+                    <div id="div3">
+                        <div id="div4">
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </body>
+</html>
diff --git a/tests/ref/abs_rel_explicit_height_ref.html b/tests/ref/abs_rel_explicit_height_ref.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+    <html>
+        <head>
+            <style type="text/css">
+                * {
+                    margin: 0;
+                }
+                #div0 {
+                    position: absolute;
+                    height: 100px;
+                    width: 100%;
+                    background-color: green;
+                }
+            </style>
+        </head>
+    <body>
+        <div id="div0">
+        </div>
+    </body>
+</html>
diff --git a/tests/ref/basic.list b/tests/ref/basic.list
@@ -9,6 +9,7 @@
 # Should be == with expected failure:
 fragment=top != ../html/acid2.html acid2_ref.html
 
+== abs_rel_explicit_height.html abs_rel_explicit_height_ref.html
 == absolute_inline_containing_block_a.html absolute_inline_containing_block_ref.html
 == acid1_a.html acid1_b.html
 == acid2_noscroll.html acid2_ref_broken.html