alhudz opened a new pull request, #1762: URL: https://github.com/apache/commons-lang/pull/1762
- [x] Read the [contribution guidelines](CONTRIBUTING.md) for this project. - [ ] Read the [ASF Generative Tooling Guidance](https://www.apache.org/legal/generative-tooling.html) if you use Artificial Intelligence (AI). - [ ] I used AI to create any part of, or all of, this pull request. Which AI tool was used to create this pull request, and to what extent did it contribute? - [x] Run a successful build using the default [Maven](https://maven.apache.org/) goal with `mvn`; that's `mvn` on the command line by itself. - [x] Write unit tests that match behavioral changes, where the tests fail if the changes to the runtime are not applied. This may not always be possible, but it is a best practice. - [x] Write a pull request description that is detailed enough to understand what the pull request does, how, and why. - [x] Each commit in the pull request should have a meaningful subject line and body. Note that a maintainer may squash commits during the merge process. `Repro`: `FastDateFormat.getInstance("YYYY").format(cal)` where `cal` is 15 July 42 BC, that is a `GregorianCalendar` with `ERA` set to `GregorianCalendar.BC`. `Expected`: `-0041`, what `SimpleDateFormat` prints for the same date and pattern. `Actual`: `000` followed by `U+0007`. `YY` gives `,/` against `SimpleDateFormat`'s `-41`. 1. `GregorianCalendar.getWeekYear()` is proleptic, so a BC date gives a negative week year (`-41` here) and `WeekYear` hands it to the wrapped `NumberRule` unchanged. 2. The digit rules build each character arithmetically (`(char) (value + '0')`, `value / 10 + '0'`), so a negative value walks below `'0'` and lands on control characters or unrelated code points rather than digits. `Fix`: emit the sign in `WeekYear` and pass the magnitude down, the same handling `TimeZoneNumberRule` and `Iso8601_Rule` already apply to negative UTC offsets. Every other rule takes its value from `Calendar.get`, which never returns a negative, so `getWeekYear` is the only source of one; `YYY` and `Y` keep the four-digit padding the class Javadoc describes. Checked `YYYY` against `SimpleDateFormat` over 46,667 dates spanning 249 BC to 4188 AD: 2,611 mismatches before this change, 337 of them carrying a control character, and 0 after. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
