From c5f1f36119c4dfd7f1df681a347e8f19e8716f51 Mon Sep 17 00:00:00 2001
From: Tim Ledbetter <tim.ledbetter@ladybird.org>
Date: Thu, 17 Apr 2025 13:40:05 +0100
Subject: [PATCH] LibWeb: Allow multiple values for
 `transition-timing-function` property

---
 .../LibWeb/CSS/Parser/PropertyParsing.cpp     |  4 ++
 .../transition-timing-function-valid.txt      | 28 +++++++++++++
 .../transition-timing-function-valid.html     | 42 +++++++++++++++++++
 3 files changed, 74 insertions(+)
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-transitions/parsing/transition-timing-function-valid.txt
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-transitions/parsing/transition-timing-function-valid.html

diff --git a/Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp b/Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp
index 657bcbc0f41..fc5cf49f778 100644
--- a/Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp
+++ b/Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp
@@ -674,6 +674,10 @@ Parser::ParseErrorOr<NonnullRefPtr<CSSStyleValue const>> Parser::parse_css_value
         if (auto parsed_value = parse_transition_property_value(tokens); parsed_value && !tokens.has_next_token())
             return parsed_value.release_nonnull();
         return ParseError::SyntaxError;
+    case PropertyID::TransitionTimingFunction:
+        if (auto parsed_value = parse_comma_separated_value_list(tokens, [this](auto& tokens) { return parse_easing_value(tokens); }))
+            return parsed_value.release_nonnull();
+        return ParseError::SyntaxError;
     case PropertyID::Translate:
         if (auto parsed_value = parse_translate_value(tokens); parsed_value && !tokens.has_next_token())
             return parsed_value.release_nonnull();
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-transitions/parsing/transition-timing-function-valid.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-transitions/parsing/transition-timing-function-valid.txt
new file mode 100644
index 00000000000..952a8458826
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-transitions/parsing/transition-timing-function-valid.txt
@@ -0,0 +1,28 @@
+Harness status: OK
+
+Found 22 tests
+
+21 Pass
+1 Fail
+Pass	e.style['transition-timing-function'] = "linear" should set the property value
+Pass	e.style['transition-timing-function'] = "linear(0 0%, 0.5 50%, 1 100%)" should set the property value
+Pass	e.style['transition-timing-function'] = "linear(0 0%, 10 10%, 10 50%, 25.4 75%, 100 100%)" should set the property value
+Pass	e.style['transition-timing-function'] = "linear(0 0%, 1 100%)" should set the property value
+Pass	e.style['transition-timing-function'] = "ease" should set the property value
+Pass	e.style['transition-timing-function'] = "ease-in" should set the property value
+Pass	e.style['transition-timing-function'] = "ease-out" should set the property value
+Pass	e.style['transition-timing-function'] = "ease-in-out" should set the property value
+Pass	e.style['transition-timing-function'] = "cubic-bezier(0.1, 0.2, 0.8, 0.9)" should set the property value
+Pass	e.style['transition-timing-function'] = "cubic-bezier(0, -2, 1, 3)" should set the property value
+Pass	e.style['transition-timing-function'] = "cubic-bezier(0, 0.7, 1, 1.3)" should set the property value
+Pass	e.style['transition-timing-function'] = "step-start" should set the property value
+Pass	e.style['transition-timing-function'] = "step-end" should set the property value
+Pass	e.style['transition-timing-function'] = "steps(4)" should set the property value
+Pass	e.style['transition-timing-function'] = "steps(4, start)" should set the property value
+Pass	e.style['transition-timing-function'] = "steps(2, end)" should set the property value
+Pass	e.style['transition-timing-function'] = "steps(2, jump-start)" should set the property value
+Pass	e.style['transition-timing-function'] = "steps(2, jump-end)" should set the property value
+Pass	e.style['transition-timing-function'] = "steps(2, jump-both)" should set the property value
+Pass	e.style['transition-timing-function'] = "steps(2, jump-none)" should set the property value
+Fail	e.style['transition-timing-function'] = "steps(sibling-index(), jump-none)" should set the property value
+Pass	e.style['transition-timing-function'] = "linear, ease, linear" should set the property value
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-transitions/parsing/transition-timing-function-valid.html b/Tests/LibWeb/Text/input/wpt-import/css/css-transitions/parsing/transition-timing-function-valid.html
new file mode 100644
index 00000000000..bcc6973496d
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-transitions/parsing/transition-timing-function-valid.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Transitions: parsing transition-timing-function with valid values</title>
+<link rel="help" href="https://drafts.csswg.org/css-transitions/#propdef-transition-timing-function">
+<link rel="help" href="https://drafts.csswg.org/css-easing-1/#typedef-timing-function">
+<meta name="assert" content="transition-timing-function supports the full grammar '<timing-function> #'.">
+<script src="../../../resources/testharness.js"></script>
+<script src="../../../resources/testharnessreport.js"></script>
+<script src="../../../css/support/parsing-testcommon.js"></script>
+</head>
+<body>
+<script>
+test_valid_value("transition-timing-function", "linear");
+test_valid_value("transition-timing-function", "linear(0 0%, 0.5 50%, 1 100%)");
+test_valid_value("transition-timing-function", "linear(0 0%, 10 10%, 10 50%, 25.4 75%, 100 100%)");
+test_valid_value("transition-timing-function", "linear(0 0%, 1 100%)");
+
+test_valid_value("transition-timing-function", "ease");
+test_valid_value("transition-timing-function", "ease-in");
+test_valid_value("transition-timing-function", "ease-out");
+test_valid_value("transition-timing-function", "ease-in-out");
+test_valid_value("transition-timing-function", "cubic-bezier(0.1, 0.2, 0.8, 0.9)");
+test_valid_value("transition-timing-function", "cubic-bezier(0, -2, 1, 3)");
+test_valid_value("transition-timing-function", "cubic-bezier(0, 0.7, 1, 1.3)");
+
+test_valid_value("transition-timing-function", "step-start", "steps(1, start)");
+test_valid_value("transition-timing-function", "step-end", "steps(1)");
+test_valid_value("transition-timing-function", "steps(4)");
+test_valid_value("transition-timing-function", "steps(4, start)");
+test_valid_value("transition-timing-function", "steps(2, end)", "steps(2)");
+test_valid_value("transition-timing-function", "steps(2, jump-start)");
+test_valid_value("transition-timing-function", "steps(2, jump-end)", "steps(2)");
+test_valid_value("transition-timing-function", "steps(2, jump-both)");
+test_valid_value("transition-timing-function", "steps(2, jump-none)");
+test_valid_value("transition-timing-function", "steps(sibling-index(), jump-none)");
+
+test_valid_value("transition-timing-function", "linear, ease, linear");
+</script>
+</body>
+</html>