DateTimeFormatter.forPattern inconsistency with US Locale and SimpleDateFormatter when parsing weeks

[victornoel]

Key information

• Joda-Time version: 2.13.0
• Result of TimeZone.getDefault(): sun.util.calendar.ZoneInfo[id="UTC",offset=0,dstSavings=0,useDaylight=false,transitions=0,lastRule=null]
• Result of DateTimeZone.getDefault(): UTC

Problem description

SimpleDateFormatter is dependent on the Locale and in particular for the pattern yyyy-'W'ww, it will return different weeks numbers:

jshell> new java.text.SimpleDateFormat("yyyy-'W'ww", Locale.US).format(new Date(2022-1900, 12-1, 26))
$11 ==> "2022-W53"

jshell> new java.text.SimpleDateFormat("yyyy-'W'ww", Locale.UK).format(new Date(2022-1900, 12-1, 26))
$12 ==> "2022-W52"

On the other hand, DateTimeFormatter.forPattern will refuse, even when using Locale.US, to parse week 53 and anyway will return an incorrect date for the US locale and one of the week before.

Test case

The following works for Locale.UK but not Locale.US:

var date = new Date(2022-1900, 12-1, 26);
var locale = Locale.US;
var pattern = "yyyy-'W'ww";
assertEquals(
    new Date(
        new DateTimeFormatter.forPattern(pattern).withLocale(locale).parseMillis(
            new SimpleDateFormat(pattern, locale).format(date)
        )
    ),
    date
);