LibWeb: Ensure enumerated attributes are always limited to known values

Previously, the invalid value default wasn't taken into account when
determining the value that should be returned from the getter of an
enumerated attribute. This caused a crash when an enumerated attribute
of type DOMString? was set to an invalid value.

Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp

@@ -2962,6 +2962,7 @@ JS_DEFINE_NATIVE_FUNCTION(@class_name@::@attribute.getter_callback@)
 )~~~");
         }
 
+        // https://html.spec.whatwg.org/multipage/common-dom-interfaces.html#reflecting-content-attributes-in-idl-attributes
         if (attribute.extended_attributes.contains("Reflect")) {
             if (attribute.type->name() == "DOMString") {
                 if (!attribute.type->is_nullable()) {
@@ -2993,26 +2994,32 @@ JS_DEFINE_NATIVE_FUNCTION(@class_name@::@attribute.getter_callback@)
                         auto valid_enumerations = interface.enumerations.get(valid_enumerations_type).value();
 
                         auto missing_value_default = valid_enumerations.extended_attributes.get("MissingValueDefault");
+                        auto invalid_value_default = valid_enumerations.extended_attributes.get("InvalidValueDefault");
 
-                        attribute_generator.set("has_missing_enum_default", missing_value_default.has_value() ? "true"sv : "false"sv);
                         attribute_generator.set("missing_enum_default_value", missing_value_default.has_value() ? missing_value_default.value().view() : ""sv);
-                        attribute_generator.set("valid_enum_values", MUST(String::join(", "sv, valid_enumerations.values.values(), "\"{}\"sv"sv)));
-                        attribute_generator.append(R"~~~(
-    auto valid_values = Vector { @valid_enum_values@ };
-)~~~");
+                        attribute_generator.set("invalid_enum_default_value", invalid_value_default.has_value() ? invalid_value_default.value().view() : ""sv);
+                        attribute_generator.set("valid_enum_values", MUST(String::join(", "sv, valid_enumerations.values.values(), "\"{}\"_string"sv)));
 
                         // 1. If contentAttributeValue does not correspond to any state of attributeDefinition (e.g., it is null and there is no missing value default),
                         //    or that it is in a state of attributeDefinition with no associated keyword value, then return the empty string.
+                        //    NOTE: @invalid_enum_default_value@ is set to the empty string if it isn't present.
                         attribute_generator.append(R"~~~(
-    if (!valid_values.contains_slow(retval)) {
-        retval = {};
-    }
-    )~~~");
-                        attribute_generator.append(R"~~~(
-    auto has_default_value = @has_missing_enum_default@;
-    if (!contentAttributeValue.has_value() && has_default_value) {
+    if (!contentAttributeValue.has_value())
         retval = "@missing_enum_default_value@"_string;
+
+    Array valid_values { @valid_enum_values@ };
+    
+    auto found = false;
+    for (auto const& value : valid_values) {
+        if (value.equals_ignoring_ascii_case(retval)) {
+            found = true;
+            retval = value;
+            break;
+        }
     }
+
+    if (!found)
+        retval = "@invalid_enum_default_value@"_string;
     )~~~");
 
                         // 2. Return the canonical keyword for the state of attributeDefinition that contentAttributeValue corresponds to.
@@ -3029,8 +3036,7 @@ JS_DEFINE_NATIVE_FUNCTION(@class_name@::@attribute.getter_callback@)
                     // 8. Return the canonical keyword for the state of attributeDefinition that contentAttributeValue corresponds to.
                     // NOTE: We run step 8 here to have a field to assign to
                     attribute_generator.append(R"~~~(
-    auto retval = impl->attribute(HTML::AttributeNames::@attribute.reflect_name@);
-    auto contentAttributeValue = retval.value_or(String {});
+    auto retval = impl->attribute(HTML::AttributeNames::@attribute.reflect_name@);    
 )~~~");
 
                     // 3. Let attributeDefinition be the attribute definition of element's content attribute whose namespace is null
@@ -3047,14 +3053,45 @@ JS_DEFINE_NATIVE_FUNCTION(@class_name@::@attribute.getter_callback@)
                     auto valid_enumerations_type = attribute.extended_attributes.get("Enumerated").value();
                     auto valid_enumerations = interface.enumerations.get(valid_enumerations_type).value();
 
-                    attribute_generator.set("valid_enum_values", MUST(String::join(", "sv, valid_enumerations.values.values(), "\"{}\"sv"sv)));
+                    auto missing_value_default = valid_enumerations.extended_attributes.get("MissingValueDefault");
+                    auto invalid_value_default = valid_enumerations.extended_attributes.get("InvalidValueDefault");
+
+                    attribute_generator.set("missing_enum_default_value", missing_value_default.has_value() ? missing_value_default.value().view() : ""sv);
+                    attribute_generator.set("invalid_enum_default_value", invalid_value_default.has_value() ? invalid_value_default.value().view() : ""sv);
+                    attribute_generator.set("valid_enum_values", MUST(String::join(", "sv, valid_enumerations.values.values(), "\"{}\"_string"sv)));
+
                     attribute_generator.append(R"~~~(
-    auto valid_values = Vector { @valid_enum_values@ };
-)~~~");
+    Array valid_values { @valid_enum_values@ };
+    )~~~");
+                    if (invalid_value_default.has_value()) {
+                        attribute_generator.append(R"~~~(
+    
+    if (retval.has_value()) {
+        auto found = false;
+        for (auto const& value : valid_values) {
+            if (value.equals_ignoring_ascii_case(retval.value())) {
+                found = true;
+                retval = value;
+                break;
+            }
+        }
+
+        if (!found)
+            retval = "@invalid_enum_default_value@"_string;
+    }
+    )~~~");
+                    }
+
+                    if (missing_value_default.has_value()) {
+                        attribute_generator.append(R"~~~(
+    if (!retval.has_value())
+        retval = "@missing_enum_default_value@"_string;
+    )~~~");
+                    }
+
                     attribute_generator.append(R"~~~(
-    VERIFY(valid_values.contains_slow(contentAttributeValue));
+    VERIFY(!retval.has_value() || valid_values.contains_slow(retval.value()));
 )~~~");
-
                     // FIXME: 7. If contentAttributeValue corresponds to a state of attributeDefinition with no associated keyword value, then return null.
                 }
             } else if (attribute.type->name() != "boolean") {

Tests/LibWeb/Text/expected/HTML/button-attributes.txt

@@ -1,3 +1,5 @@
 submit
 button
+button
+submit
 submit

Tests/LibWeb/Text/input/HTML/button-attributes.html

@@ -5,6 +5,10 @@
         println(button.type);
         button.setAttribute("type", "button");
         println(button.type);
+        button.setAttribute("type", "BUTTON");
+        println(button.type);
+        button.setAttribute("type", "invalid");
+        println(button.type);
         button.removeAttribute("type");
         println(button.type);
     });