Missing warnings in modifying partial downloaded data with some tools (e.g. splitting ways)

[segubi]

If I delete an item in an area outside the boundaries of downloaded data (or especially if I download subsets of the data via overpass) I get a warning, that these may be part of a relation.

The same warning has to be given if one splits one way, because josm doesn't check (for example during the uploading process) whether the newly created way should be included in eventual parent relations.

The result is that routes get interrupted without warning.

I checked the tools and suggest:

The logic and structural consistency can be disrupted with the following tools, therefore the warning should at least added in:

• split ways
• reverse ways
• disconnecting nodes from ways (it may also interrupt routes with connecting ways which are not visible)
• merge nodes (produces conflicts)

Maybe it could be also advisable for the other tools which are able to destruct the geometry of dependent items:

• Align nodes in line
• Distribute nodes
• Orthogonalize shape
• Mirror

It is already included in:
deleting items, combine ways, simplify ways, unglue ways, join areas

Align nodes in circle behaves differently: It gives no warning if I use it with incomplete data of an overpass-download, and it is completely disabled if I try to adjust a way with a node outside the downloaded data area. A warning (in both cases) as in the other tools would be more appropriate.

[skyper]

For Split way, see #17898 with some pros and cons about too many warning outside download area.

Working outside download area or without any, should not be encouraged and supported by too many warnings.
Especially, without any download area user should care about parent objects and know about the risks. Denying actions on the other hand, like Align nodes in circle/line will make some advanced users, including myself, unhappy.

+1, for a warnings for merge nodes, as any deletion of node should be handled identical
+1, for a notification for disconnecting, as unglue and disconnect should show the identical notifications

reverse ways is quite special, as all nodes might be checked for parent relations, so I am unsure about it right now.

[segubi]

Thanks for the comment. #17898 and the discussion shows nearly all issues I wanted to mention. Maybe the tickets should be merged?

You write "Working outside download area or without any, should not be encouraged and supported by too many warnings. Especially, without any download area user should care about parent objects and know about the risks."

I think, the warnings wouldn't be encouraging. If I just start working without download area - i.e. using overpass downloads - I would be happy about the warnings to learn from, maybe they could be turned off if I really have understood the issue. Would be better to see the warning some times more often than only once...

I am working on relations over quite big areas which aren't downloadable completely. I just learned about the problem as I looked up precisely what happened to "my" relations that were sometimes disrupted by others. I am afraid that I have done the same thing to other relations as well. Will be a lot of work looking through my changesets. I didn't get complaints on this so far, but it takes quite a time to recognize small breaches in the routes...