Lee Carré (2021-12-01 17:24:15+00:00): “about the "other guideline", […] it is more or less derived from ACID properties in databases and good practices when pushing commits in codebases.”

I'm familiar. It's a good point.

The problem is a result of multiple factors.

Ideally, yes, a single changeset when making country-wide changes of the same type (e.g. to the same key on multiple elements). Unfortunately, especially for Jersey, the ‘noise’ of large irrelevant changesets then exceeds the ‘signal’ of locally-relevant ones. With no viable solution, it seems.

However, tagging the changeset is a good idea; much simpler than anything else I've seen discussed.

“about OSMCha, but maybe it's something that its developers would accept to consider?”

I would certainly hope so. Shouldn't be difficult to implement. The developers seem to have been thinking in terms of finding specific changesets, rather than filtering out non-local sets. So, it likely just hasn't occured to them to implement negation; it does what they currently need.

I'll try to find some time to search for any existing issues about the same problem / request.

However, it would be much more compelling if whole-France sets were already being tagged #France in order to show real-world need for the change (and to give developers something to test against).

Otherwise it may simply be ignored as a wish-list feature.

Bit of a chicken-and-egg problem, as is common with tech 😋.

“The filtering could be done on a polygon (that would work on all changesets) or on a regexp on the comments (that would require some effort from French contributors).”

Currently I use polygon-based filtering. The problem with that, is that in order to exclude enough noise to be worthwhile, it also ends up excluding large sets which DO make locally-relevant changes. For example, when someone updates the tagging of a chain of shops across the whole British Isles; filtering excludes that set because it's much larger than Jersey, yet the set makes local changes.
Otherwise, back to the original problem; more irrelevant sets (that have a bounding box which includes Jersey) which make zero local changes are still included in the local list of changesets, and overwhelmingly outnumber the locally-relevant sets.

Hence being most interested in your suggestion of simply tagging such sets in a way which makes them easy to filter out. Anything else is a lot more complicated (and even if possible, won't be implemented for a long time).

Your suggestion is simple enough that it should be possible to automate the tagging of changesets, rather than requiring all French mappers to change their habits (which leaves the problem of there always being newbies who don't yet know to add #France).

“I sincerely hope you and contributors who are more expert than me will be able to find and implement a solution that works.”

As do I. Yours is the most promising suggestion, so far. Thankyou for your thoughtful ideas.

Just for my own understanding; how much do you estimate would be involved in having all whole-France changesets tagged with #France? Besides avoiding of guesswork, I'm also completely unfamiliar with the French OSM community.

“Otherwise, you'll just need a vote from your fellow citizens to change the geography 🙂”

Ha! 😁
I won't hold much hope for that. Our politicians struggle with much more basic concerns.

Maybe if the outcome of the Battle of Jersey had been different, than this would be a moot point and we'd be conversing in French.

It would certainly make the current dispute re fishing (post-Brexit) a whole lot simpler, too 😄.