LibJS: Check PlainMonthDay is in the ISO date time limits in creation

This is a normative change in the Temporal spec.

See: https://github.com/tc39/proposal-temporal/commit/374305c

2 files changed, 17 insertions, 7 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/PlainMonthDay.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/PlainMonthDay.cpp
index 85d21549e9..fbf8d44b25 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/PlainMonthDay.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/PlainMonthDay.cpp
@@ -155,18 +155,22 @@ ThrowCompletionOr<PlainMonthDay*> create_temporal_month_day(GlobalObject& global
     if (!is_valid_iso_date(reference_iso_year, iso_month, iso_day))
         return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainMonthDay);
 
-    // 4. If newTarget is not present, set newTarget to %Temporal.PlainMonthDay%.
+    // 4. If ISODateTimeWithinLimits(referenceISOYear, isoMonth, isoDay, 12, 0, 0, 0, 0, 0) is false, throw a RangeError exception.
+    if (!iso_date_time_within_limits(global_object, reference_iso_year, iso_month, iso_day, 12, 0, 0, 0, 0, 0))
+        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainMonthDay);
+
+    // 5. If newTarget is not present, set newTarget to %Temporal.PlainMonthDay%.
     if (!new_target)
         new_target = global_object.temporal_plain_month_day_constructor();
 
-    // 5. Let object be ? OrdinaryCreateFromConstructor(newTarget, "%Temporal.PlainMonthDay.prototype%", « [[InitializedTemporalMonthDay]], [[ISOMonth]], [[ISODay]], [[ISOYear]], [[Calendar]] »).
-    // 6. Set object.[[ISOMonth]] to isoMonth.
-    // 7. Set object.[[ISODay]] to isoDay.
-    // 8. Set object.[[Calendar]] to calendar.
-    // 9. Set object.[[ISOYear]] to referenceISOYear.
+    // 6. Let object be ? OrdinaryCreateFromConstructor(newTarget, "%Temporal.PlainMonthDay.prototype%", « [[InitializedTemporalMonthDay]], [[ISOMonth]], [[ISODay]], [[ISOYear]], [[Calendar]] »).
+    // 7. Set object.[[ISOMonth]] to isoMonth.
+    // 8. Set object.[[ISODay]] to isoDay.
+    // 9. Set object.[[Calendar]] to calendar.
+    // 10. Set object.[[ISOYear]] to referenceISOYear.
     auto* object = TRY(ordinary_create_from_constructor<PlainMonthDay>(global_object, *new_target, &GlobalObject::temporal_plain_month_day_prototype, iso_month, iso_day, reference_iso_year, calendar));
 
-    // 10. Return object.
+    // 11. Return object.
     return object;
 }
 
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.js
index fc5b315382..109d01e28f 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.js
@@ -37,6 +37,12 @@ describe("errors", () => {
             new Temporal.PlainMonthDay(1, 0);
         }).toThrowWithMessage(RangeError, "Invalid plain month day");
     });
+
+    test("not within iso date time limit", () => {
+        expect(() => {
+            new Temporal.PlainMonthDay(9, 30, "iso8601", 999_999_999_999_999);
+        }).toThrowWithMessage(RangeError, "Invalid plain month day");
+    });
 });
 
 describe("normal behavior", () => {