[I] [Bug] Negative time-of-day when casting pre-epoch timestamp to TIME [paimon]

["thswlsqls (via GitHub)" <gi...@apache.org>]

thswlsqls opened a new issue, #8766:
URL: https://github.com/apache/paimon/issues/8766

   **Search before asking**
   - [x] I searched in the [issues](https://github.com/apache/paimon/issues) and found nothing similar.
   
   **Paimon version**
   master @ 345526e26
   
   **Compute Engine**
   Engine-agnostic (core) — casting in paimon-common
   
   **Minimal reproduce step**
   Cast a pre-epoch `TIMESTAMP` to `TIME`. `TimestampToTimeCastRule.create()` (paimon-common/src/main/java/org/apache/paimon/casting/TimestampToTimeCastRule.java line 48) computes the time-of-day as `value.getMillisecond() % MILLIS_PER_DAY`. For a negative millisecond (before 1970-01-01) Java's `%` returns a negative remainder, so the TIME internal value falls outside the valid millis-of-day range `[0, 86_399_999]`.
   
   Example: `1969-12-31 23:00:00` has millisecond `-3_600_000`; `-3_600_000 % 86_400_000 = -3_600_000` instead of `82_800_000` (23:00:00).
   
   **What doesn't meet your expectations?**
   Expected the cast to yield `23:00:00` (82_800_000). Actual result is a negative, invalid time-of-day.
   
   **Anything else?**
   The sibling `TIMESTAMP_WITH_LOCAL_TIME_ZONE` branch delegates to `DateTimeUtils.timestampWithLocalZoneToTime` (always valid), and `DateTimeUtils.formatTimestampMillis` already normalizes negatives (`while (time < 0) time += MILLIS_PER_DAY`). Only the modulo branch omits normalization. Fix: use `Math.floorMod`.
   
   **Are you willing to submit a PR?**
   - [x] I'm willing to submit a PR!
   
   


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Re: [I] [Bug] Negative time-of-day when casting pre-epoch timestamp to TIME [paimon]

["JingsongLi (via GitHub)" <gi...@apache.org>]

JingsongLi closed issue #8766: [Bug] Negative time-of-day when casting pre-epoch timestamp to TIME
URL: https://github.com/apache/paimon/issues/8766


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