LibJS: Fix production for time zone name in time zone strings

This is a normative change in the Temporal spec.

See:
- https://github.com/tc39/proposal-temporal/commit/caf013a
- https://github.com/tc39/proposal-temporal/commit/fb7cfa6

Userland/Libraries/LibJS/Runtime/Temporal/AbstractOperations.cpp

@@ -1695,10 +1695,10 @@ ThrowCompletionOr<TemporalTimeZone> parse_temporal_time_zone_string(GlobalObject
     if (!parse_result.has_value())
         return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidTimeZoneString, iso_string);
 
-    // 3. Let each of z, offsetString, and name be the source text matched by the respective UTCDesignator, TimeZoneNumericUTCOffset, and TimeZoneIANAName Parse Node contained within parseResult, or an empty sequence of code points if not present.
+    // 3. Let each of z, offsetString, and name be the source text matched by the respective UTCDesignator, TimeZoneNumericUTCOffset, and TimeZoneIdentifier Parse Nodes contained within parseResult, or an empty sequence of code points if not present.
     auto z = parse_result->utc_designator;
     auto offset_string = parse_result->time_zone_numeric_utc_offset;
-    auto name = parse_result->time_zone_iana_name;
+    auto name = parse_result->time_zone_identifier;
 
     // 4. If name is empty, then
     //     a. Set name to undefined.

Userland/Libraries/LibJS/Runtime/Temporal/ISO8601.cpp

@@ -935,15 +935,8 @@ bool ISO8601Parser::parse_time_zone_iana_name()
         transaction.commit();
         return true;
     };
-    StateTransaction transaction { *this };
-    if (parse_etc_gmt_with_offset()) {
-        // no-op.
-    } else if (!parse_time_zone_iana_name_tail()) {
-        return false;
-    }
-    m_state.parse_result.time_zone_iana_name = transaction.parsed_string_view();
-    transaction.commit();
-    return true;
+    return parse_etc_gmt_with_offset()
+        || parse_time_zone_iana_name_tail();
 }
 
 // https://tc39.es/proposal-temporal/#prod-TimeZoneIdentifier
@@ -958,6 +951,7 @@ bool ISO8601Parser::parse_time_zone_identifier()
     } else if (!parse_time_zone_utc_offset_name()) {
         return false;
     }
+    m_state.parse_result.time_zone_identifier = transaction.parsed_string_view();
     transaction.commit();
     return true;
 }

Userland/Libraries/LibJS/Runtime/Temporal/ISO8601.h

@@ -37,7 +37,7 @@ struct ParseResult {
     Optional<StringView> time_zone_utc_offset_minute;
     Optional<StringView> time_zone_utc_offset_second;
     Optional<StringView> time_zone_utc_offset_fraction;
-    Optional<StringView> time_zone_iana_name;
+    Optional<StringView> time_zone_identifier;
     Optional<StringView> duration_years;
     Optional<StringView> duration_months;
     Optional<StringView> duration_weeks;

Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp

@@ -449,25 +449,13 @@ ThrowCompletionOr<Object*> to_temporal_time_zone(GlobalObject& global_object, Va
     // 3. Let parseResult be ? ParseTemporalTimeZoneString(identifier).
     auto parse_result = TRY(parse_temporal_time_zone_string(global_object, identifier));
 
-    // TODO: This currently cannot be tested as ParseTemporalTimeZoneString only considers
-    //       TimeZoneIANAName for the returned [[Name]] slot, not TimeZoneUTCOffsetName.
-    //       So when we provide a numeric time zone offset, this branch won't be executed,
-    //       and if we provide an IANA name, it won't be a valid TimeZoneNumericUTCOffset.
-    //       This should be fixed by: https://github.com/tc39/proposal-temporal/pull/2200
-
     // 4. If parseResult.[[Name]] is not undefined, then
     if (parse_result.name.has_value()) {
         // a. Let name be parseResult.[[Name]].
         auto name = parse_result.name.release_value();
 
-        // b. If ParseText(StringToCodePoints(name, TimeZoneNumericUTCOffset)) is not a List of errors, then
-        if (is_valid_time_zone_numeric_utc_offset_syntax(name)) {
-            // i. If parseResult.[[OffsetString]] is not undefined, and ! ParseTimeZoneOffsetString(parseResult.[[OffsetString]]) ≠ ! ParseTimeZoneOffsetString(name), throw a RangeError exception.
-            if (parse_result.offset_string.has_value() && (MUST(parse_time_zone_offset_string(global_object, *parse_result.offset_string)) != MUST(parse_time_zone_offset_string(global_object, name))))
-                return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalTimeZoneOffsetStringMismatch, *parse_result.offset_string, name);
-        }
-        // c. Else,
-        else {
+        // b. If ParseText(StringToCodePoints(name, TimeZoneNumericUTCOffset)) is a List of errors, then
+        if (!is_valid_time_zone_numeric_utc_offset_syntax(name)) {
             // i. If IsValidTimeZoneName(name) is false, throw a RangeError exception.
             if (!is_valid_time_zone_name(name))
                 return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidTimeZoneName, name);

Userland/Libraries/LibJS/Tests/builtins/Temporal/TimeZone/TimeZone.from.js

@@ -25,18 +25,18 @@ describe("normal behavior", () => {
             ["Europe/London", "Europe/London"],
             ["Europe/Isle_of_Man", "Europe/London"],
             ["1970-01-01+01", "+01:00"],
-            ["1970-01-01+01[-12:34]", "+01:00"],
+            ["1970-01-01+01[-12:34]", "-12:34"],
             ["1970-01-01T00:00:00+01", "+01:00"],
             ["1970-01-01T00:00:00.000000000+01", "+01:00"],
             ["1970-01-01T00:00:00.000000000+01:00:00", "+01:00"],
             ["1970-01-01+12:34", "+12:34"],
             ["1970-01-01+12:34:56", "+12:34:56"],
             ["1970-01-01+12:34:56.789", "+12:34:56.789"],
-            ["1970-01-01+12:34:56.789[-01:00]", "+12:34:56.789"],
+            ["1970-01-01+12:34:56.789[-01:00]", "-01:00"],
             ["1970-01-01-12:34", "-12:34"],
             ["1970-01-01-12:34:56", "-12:34:56"],
             ["1970-01-01-12:34:56.789", "-12:34:56.789"],
-            ["1970-01-01-12:34:56.789[+01:00]", "-12:34:56.789"],
+            ["1970-01-01-12:34:56.789[+01:00]", "+01:00"],
         ];
         for (const [arg, expected] of values) {
             expect(Temporal.TimeZone.from(arg).id).toBe(expected);