RFR: 8276766: Enable jar and jmod to produce deterministic timestamped content [v4]

[Andrew Leonard]

On Wed, 24 Nov 2021 19:40:38 GMT, Mark Reinhold <mr at openjdk.org> wrote:

> A user who’s not familiar with the lingo of [reproducible builds](https://reproducible-builds.org/docs/source-date-epoch/) will be mystified by an option named `--source-date`. A user who just wants to set the timestamp of new entries won’t be looking for an option whose name includes “source.”
> 
> Please consider providing a more general option, say `--date`, which takes an [ISO 8601 date/time string](https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/time/format/DateTimeFormatter.html#ISO_DATE_TIME). That would solve the general problem while also satisfying the requirement for reproducible builds. In the build it’s easy enough to convert the seconds-since epoch value of `SOURCE_DATE_EPOCH` to an ISO 8601 string (`date -d @$SOURCE_DATE_EPOCH --iso-8601=seconds`).

Thanks @mbreinhold , good point, i'll update to use --date=<iso-8601-date\>

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PR: https://git.openjdk.java.net/jdk/pull/6481