adiffs.osmcha.org only seems to provide changesets after 2024-11-26

[Robbendebiene]

Thanks for providing a convenient way to access adiffs via changeset ids.

I noticed that https://adiffs.osmcha.org/changesets/%ID%.adiff doesn't seem to work for older changesets like for example https://www.openstreetmap.org/changeset/155974562 The oldest changeset adiff I was able to find is timestamped as 2024-11-26. Also this seems to be the only adiff containing a changeset element.

It looks like the changeset adiff generation has been started with a specific planet dump. Is this bevaiour intentional?

[jake-low]

You're correct, data isn't available yet for changesets before 2024-11-26, which is when the first version of the service went online. I should have added a note about that in the README; sorry about that.

The service relies on comparing edits from the planet.openstreetmap.org replication stream against a local mirror of the planet data. It is possible to generate data for old changesets by downloading an old planet file and then replaying old replication files on top of it, generating augmented diffs along the way. I plan to do this, but I've waited to do so because there are a few bugs in the diff generator (including #1) that I'd like to fix first, before spending a ton of compute power on creating diffs for old changesets.

Also this seems to be the only adiff containing a changeset element.

You've actually stumbled upon an (accidental) preview of a planned feature: I'm hoping to include changeset metadata like this in all changesets, but haven't deployed the code to do so yet. A handful of the earliest available changesets have that data due to a deployment error I made during development.

Once I've fixed the outstanding bugs with the diff generator and finished adding support for changeset metadata, I'll backfill as much old data as I can afford compute resources for.

[Robbendebiene]

Thanks for the quick and detailed clarification 🙏