Deprecate micropackaging

[astrojuanlu]

After some cool-off period in #3750, we saw no indication that users have a desire of keeping our micropackaging functionality, so we decided to eventually remove it.

The first step is to deprecate it for the present 0.19.x cycle.

Every time a user uses kedro micropkg a DeprecationWarning should be shown (or equivalent, see discussion about FutureWarning and DeprecationWarning in various places, for example #2744 (comment))

Since kedro.framework.cli.micropkg is public API too, this warning should also be shown when importing anything from that subpackage.

The warning should communicate to users that this functionality is no longer maintained and will be deleted in Kedro 0.20, and point them to #3750 in case they want to voice a dissenting opinion.

[yury-fedotov]

+, I think it's a nice initiative.

[arek544]

what's an alternative to micropackaging? Should I switch to packaging instead?

[astrojuanlu]

@arek544 Could you detail your use case?

[arek544]

I have multiple modular pipelines that l like to share between projects, so I thought micropackaging would be the best solution so far

[merelcht]

Hi @arek544, thanks for commenting. Micropackaging does suit your use case well and that's also the use case we built the feature for. However, adoption has been very low and most users have found alternative solutions. Are you on our Slack (http://slack.kedro.org/) by any chance? It would be good to explore a different solution for you for when the time comes that micropackaging is removed from Kedro.

[merelcht]

@astrojuanlu you wrote in the description:

Since kedro.framework.cli.micropkg is public API too, this warning should also be shown when importing anything from that subpackage.

The only public method aside from the CLI commands in kedro.framework.cli.micropkg is safe_extract: https://github.com/kedro-org/kedro/blob/main/kedro/framework/cli/micropkg.py#L393, does that really warrant an import deprecation warning? I'd be very surprised if anyone is using that since it's a pretty generic utility method.

[astrojuanlu]

Good to see most of that module is private API, wrote my comment without looking. I also doubt that anybody is using that specific function, but strictly speaking we should, right?