Now that we have a cgit lister, this should be a no brainer.
If that's the case, we need it up and running quickly.

Merged and closed related old task T2314, here is a reference on related work on Zenodo: https://blog.jupyter.org/binder-with-zenodo-af68ed6648a6

In T2942#56223, @zack wrote:

My answer is a very emphatic YES.

There are many reasons for this, including avoiding metadata pollution, encouraging people to also deposit content to the archive, and hash collision risks (if we have not archived something, there is no guarantee we will ever use the hash contained in that SWHID for the software artifact that the metadata submitter thinks is referenced by it).

Thanks Antoine, any way to have this kind of errors also reported in the admin dashboard for save code now.

It looks like you already agree, but FWIW I'd also would like to have a dedicated (micro)service that keeps an up-to-date bloom filter for the entire archive, with a REST API.
It might be useful for other use cases (swh-scanner comes to mind, but I'm sure we'll find others as time passes).

In T2912#55849, @olasd wrote:

Thanks for sketching out this proposal! It looks quite promising (and neat!).

Updated the proposal with your suggestions, thanks!

In T2912#55487, @vlorentz wrote:

A Python library may be an issue, as it requires a central process with a global lock. Sharding by hash may fix the issue, though.