From 1a3246b5600dd17516ca7622e4d69641987d6028 Mon Sep 17 00:00:00 2001
From: Sam Atkins <sam@ladybird.org>
Date: Wed, 27 Aug 2025 15:42:33 +0100
Subject: [PATCH] LibWeb/CSS: Stop allowing auto in
 ComputedProperties::length_percentage

We only had one user of this which allows `auto`, which is length_box().
So, inline the code there, remove the `auto` branch from
length_percentage(), and then remove length_percentage_or_fallback()
entirely as nobody uses it any more.
---
 Libraries/LibWeb/CSS/ComputedProperties.cpp | 54 +++++++++++++++------
 Libraries/LibWeb/CSS/ComputedProperties.h   |  1 -
 2 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/Libraries/LibWeb/CSS/ComputedProperties.cpp b/Libraries/LibWeb/CSS/ComputedProperties.cpp
index 30bfe37104a..c0ba3b49ef4 100644
--- a/Libraries/LibWeb/CSS/ComputedProperties.cpp
+++ b/Libraries/LibWeb/CSS/ComputedProperties.cpp
@@ -222,11 +222,6 @@ Size ComputedProperties::size_value(PropertyID id) const
     return Size::make_auto();
 }
 
-LengthPercentage ComputedProperties::length_percentage_or_fallback(PropertyID id, Layout::NodeWithStyle const& layout_node, ClampNegativeLengths disallow_negative_lengths, LengthPercentage const& fallback) const
-{
-    return length_percentage(id, layout_node, disallow_negative_lengths).value_or(fallback);
-}
-
 Optional<LengthPercentage> ComputedProperties::length_percentage(PropertyID id, Layout::NodeWithStyle const& layout_node, ClampNegativeLengths disallow_negative_lengths) const
 {
     auto const& value = property(id);
@@ -256,9 +251,6 @@ Optional<LengthPercentage> ComputedProperties::length_percentage(PropertyID id,
         return length;
     }
 
-    if (value.has_auto())
-        return LengthPercentage { Length::make_auto() };
-
     return {};
 }
 
@@ -269,12 +261,46 @@ Length ComputedProperties::length(PropertyID property_id) const
 
 LengthBox ComputedProperties::length_box(PropertyID left_id, PropertyID top_id, PropertyID right_id, PropertyID bottom_id, Layout::NodeWithStyle const& layout_node, ClampNegativeLengths disallow_negative_lengths, Length const& default_value) const
 {
-    LengthBox box;
-    box.left() = length_percentage_or_fallback(left_id, layout_node, disallow_negative_lengths, default_value);
-    box.top() = length_percentage_or_fallback(top_id, layout_node, disallow_negative_lengths, default_value);
-    box.right() = length_percentage_or_fallback(right_id, layout_node, disallow_negative_lengths, default_value);
-    box.bottom() = length_percentage_or_fallback(bottom_id, layout_node, disallow_negative_lengths, default_value);
-    return box;
+    auto length_box_side = [&](PropertyID id) -> LengthPercentage {
+        auto const& value = property(id);
+
+        if (value.is_calculated())
+            return LengthPercentage { value.as_calculated() };
+
+        if (value.is_percentage()) {
+            auto percentage = value.as_percentage().percentage();
+
+            // FIXME: This value can be negative as interpolation does not yet clamp values to allowed ranges - remove this
+            //        once we do that.
+            if (disallow_negative_lengths == ClampNegativeLengths::Yes && percentage.as_fraction() < 0)
+                return default_value;
+
+            return percentage;
+        }
+
+        if (value.is_length()) {
+            auto length = value.as_length().length();
+
+            // FIXME: This value can be negative as interpolation does not yet clamp values to allowed ranges - remove this
+            //        once we do that.
+            if (disallow_negative_lengths == ClampNegativeLengths::Yes && length.to_px(layout_node) < 0)
+                return default_value;
+
+            return value.as_length().length();
+        }
+
+        if (value.has_auto())
+            return LengthPercentage { Length::make_auto() };
+
+        return default_value;
+    };
+
+    return LengthBox {
+        length_box_side(top_id),
+        length_box_side(right_id),
+        length_box_side(bottom_id),
+        length_box_side(left_id)
+    };
 }
 
 Color ComputedProperties::color_or_fallback(PropertyID id, ColorResolutionContext color_resolution_context, Color fallback) const
diff --git a/Libraries/LibWeb/CSS/ComputedProperties.h b/Libraries/LibWeb/CSS/ComputedProperties.h
index cad4171509f..c4d43f23209 100644
--- a/Libraries/LibWeb/CSS/ComputedProperties.h
+++ b/Libraries/LibWeb/CSS/ComputedProperties.h
@@ -82,7 +82,6 @@ public:
         No,
         Yes,
     };
-    LengthPercentage length_percentage_or_fallback(PropertyID, Layout::NodeWithStyle const&, ClampNegativeLengths, LengthPercentage const& fallback) const;
     Optional<LengthPercentage> length_percentage(PropertyID, Layout::NodeWithStyle const&, ClampNegativeLengths) const;
     LengthBox length_box(PropertyID left_id, PropertyID top_id, PropertyID right_id, PropertyID bottom_id, Layout::NodeWithStyle const&, ClampNegativeLengths, Length const& default_value) const;
     Color color_or_fallback(PropertyID, ColorResolutionContext, Color fallback) const;