On Fri, 24 Mar 2023 18:48:41 GMT, Justin Lu <j...@openjdk.org> wrote:
>> This PR fixes the bug which occurred when `Calendar.roll(WEEK_OF_YEAR)`
>> rolled into a minimal first week with an invalid `WEEK_OF_YEAR` and
>> `DAY_OF_WEEK` combo.
>>
>> For example, Rolling _Monday, 30 December 2019_ by 1 week produced _Monday,
>> 31 December 2018_, which is incorrect. This is because `WEEK_OF_YEAR` is
>> rolled from 52 to 1, and the original `DAY_OF_WEEK` is 1. However, there is
>> no Monday in week 1 of 2019. This is exposed when a future method calls
>> `Calendar.complete()`, which eventually calculates a `fixedDate` with the
>> invalid `WEEK_OF_YEAR` and `DAY_OF_WEEK` combo.
>>
>> To prevent this, a check is added for rolls into week 1, which determines if
>> the first week is minimal. If it is indeed minimal, then it is checked if
>> `DAY_OF_WEEK` exists in that week, if not, `WEEK_OF_YEAR` must be
>> incremented by one.
>>
>> After the fix, Rolling _Monday, 30 December 2019_ by 1 week produces
>> _Monday, 7 January 2019_
>
> Justin Lu has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Remove max week methods accidentally comitted
Looks good. Mostly cosmetic comments follow
src/java.base/share/classes/java/util/GregorianCalendar.java line 1315:
> 1313: // rolling up into week 1, as the existing checks
> 1314: // sufficiently handle rolling down into week 1.
> 1315: if (newWeekOfYear == 1 && (isInvalidWeek1())) {
Extra parens around `isInvalidWeek1()`
src/java.base/share/classes/java/util/GregorianCalendar.java line 1316:
> 1314: // sufficiently handle rolling down into week 1.
> 1315: if (newWeekOfYear == 1 && (isInvalidWeek1())) {
> 1316: if (amount > 0) {
Can be folded into the above `if`
src/java.base/share/classes/java/util/GregorianCalendar.java line 3015:
> 3013: private boolean isMinWeek (int days) {
> 3014: return days >= getMinimalDaysInFirstWeek();
> 3015: }
Since this method is only used above once, maybe make the check inline?
src/java.base/share/classes/java/util/GregorianCalendar.java line 3032:
> 3030: // not between 6 7 1 2 3
> 3031: return !(day >= startDay || day <= endDay);
> 3032: }
Could be more readable if the method does not have `Not`, i.e, `daysInMinWeek`?
This would remove the negation in the return statements.
test/jdk/java/util/Calendar/RollToMinWeek.java line 28:
> 26: * @bug 8225641
> 27: * @summary Test the behavior of Calendar.roll(WEEK_OF_YEAR) when the
> last week
> 28: * is rolled up into a minimal week 1 of the same year
`minimal week 1` may be unclear.
test/jdk/java/util/Calendar/RollToMinWeek.java line 43:
> 41: /**
> 42: * Test to validate the behavior of Calendar.roll(WEEK_OF_YEAR, +1)
> 43: * when rolling into a minimal week 1 from the max week. WEEK_OF_YEAR can
IIUC, `minimal` and `max` mean `first` and `last` respectively? I'd rather
change those as it would confuse with `minimal days in the first week`.
test/jdk/java/util/Calendar/RollToMinWeek.java line 52:
> 50: public void rollUpTest(Calendar calendar, String[] validDates){
> 51: if (calendar instanceof GregorianCalendar) {
> 52: testRoll(calendar, validDates, +1);
If the amount is fixed to `+1`, no need to pass it as an argument
test/jdk/java/util/Calendar/RollToMinWeek.java line 98:
> 96: for (int firstDay = 1; firstDay <= 7; firstDay++) {
> 97: calList.add(Arguments.of(buildCalendar("gregory",
> firstDay, weekLength,
> 98: dayOfMonth, 11, 2019),
> validDates[date]));
`11` may better be replaced with `Calendar.DECEMBER`.
test/jdk/java/util/Calendar/RollToMinWeek.java line 114:
> 112: calBuilder.setDate(year, month, dayOfMonth);
> 113: return calBuilder.build();
> 114: }
`Builder` instance can be reused. Also since Builder can method chain, you
could write
static Calendar.Builder CAL_BUILDER = new Builder().setCalendarType(type);
return CAL_BUILDER
.setWeekDefinition(...)
.setDate(...)
.build();
-------------
PR Review: https://git.openjdk.org/jdk/pull/13031#pullrequestreview-1359843143
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149772051
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149771259
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149777645
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149779427
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149838007
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149838132
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149843461
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149847360
PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1149851739
