Support Maven reproducible build feature for repackage

[reitzmichnicht]

Maven introduced with the latest updates the feature to generate reproducible jars.
https://maven.apache.org/guides/mini/guide-reproducible-builds.html

It would be great if the repackage goal of the spring boot plugin would reuse the property <project.build.outputTimestamp> if available and use it for the fatjar timestamp and the zip contents itself.

This is the last obstacle of getting binary equivalent outputs for building the same git revision.

[wilkinsona]

Thanks for the suggestion. It's something that our Gradle plugin already supports so it makes sense to support it with Maven as well.

[wilkinsona]

Maven's war plugin does not make use of <project.build.outputTimestamp> so we cannot support this for war packaging. The symptom of attempting to do so is intermittent build failures as the entries in the source war file are not in the same order from build to build.

[Jurrie]

Sorry for commenting on a closed issue, but I think this needs to be reopened. I believe the maven-war-plugin is fixed because of MWAR-432 and MWAR-436. The most recent version supports <project.build.outputTimestamp> as far as I can tell. Is there something else that's holding back this issue? Should I open a different issue instead?