$toMillis: >3 fractional-second digits throw raw java.time.DateTimeException instead of truncating to millis (jsonata 2.2.1) #438

Surfaced while comparing JSONata4Java against the jsonata-js 2.2.1 test corpus during the Jackson 3 migration (#430 / PR #431). Pre-existing functional-compatibility gap vs the reference implementation (try.jsonata.org 2.2.1), not a migration regression.

$toMillis with a picture whose fractional-second component supplies more precision than milliseconds throws a raw java.time.DateTimeException instead of truncating to milliseconds like the reference.

Example:

$toMillis("2026-04-08T19:05:04.01987", "[Y0001]-[M01]-[D01]T[H01]:[m01]:[s01].[f1]")

• JSONata4Java: raw java.time.DateTimeException: Invalid value for NanoOfSecond (valid values 0 - 999999999): ...
• jsonata.org 2.2.1: truncates sub-millisecond precision to milliseconds (round-trips to ...019Z).

Expected: truncate to millisecond precision (matching the reference) rather than leaking an internal java.time.DateTimeException.

Reference: jsonata-js 2.2.1.