On Tue, 28 Mar 2023 21:06:34 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 five additional > commits since the last revision: > > - Impl cleanup, add Saturday end day conditional > - Rename test, clarify test documentation > - Add type to static declaration of Cal.Builder, since only concerned with > Gregorian for this test > - Pass in amount as 1 directly > - Reuse Calendar.Builder src/java.base/share/classes/java/util/GregorianCalendar.java line 3014: > 3012: */ > 3013: private boolean dayInMinWeek (int day, int startDay, int endDay) { > 3014: endDay = endDay == 0 Why `endDay` can be `0`? If the arguments are `Calendar.XXXDAY`, should they be between 1 to 7? In other words, why is the above calling site doing `getFirstDayOfWeek() - 1`? I'd add some range checks for the input values. test/jdk/java/util/Calendar/RollFromLastToFirstWeek.java line 52: > 50: */ > 51: public class RollFromLastToFirstWeek { > 52: static Calendar.Builder GREGORIAN_BUILDER = new Builder() Nit: `Calendar.` can be omitted (and can be `private static final`) ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1152579044 PR Review Comment: https://git.openjdk.org/jdk/pull/13031#discussion_r1152579338