Uploading incomplete mulitpolygon relations - rather block than warn?

[pch14@…]

I propose that the validator should block upload and not offer the "Continue" option, when it prompts "Incomplete multipolygon-relation modified" (may not be the exact wording). Perhaps offer a "Download elements" option instead, or, good enough, select the relation(s), so one does not have to search for it.

Rationale: Its "warning" only, but may hide an "error". Recently I destroyed a large multipolygon because I did somehow create an intersection in it. Trying to find out, how that could have happened, I guess it is because I moved a node, close to the border, maybe even outside of the downloaded data area, and later click through the warning - Blocking should not unreasonably burden mappers much as it is quick most of the time.

[skyper]

No, please, not as long as the test is not improved. See #18610.

• Why do I need all members for the check? direct member in relation's member list should be sufficient most of the time.
• The intersecting/crossing is a problem on its own and JOSM should already warn about it inside downloaded area with an own warning.
• Moving a node is a complete different case which can lead to many problems, so I rather handle the results direct after the action.
• Moving a node outside downloaded area should raise a warning.

Why is this strict warning only raised for modification of MPs. Split way, does break PTv2 relations under certain conditions, atm, but I do not get warnings about modified route relations.

[pch14@…]

Hmm, there must be more at play - just right now I pulled a node of an inner area "shingle" outside of its outer ring in a "water:river" multipoly; Hitting the upload button, no error, no warning. Everything completely downloaded. Am I confused?

[pch14@…]

I just opened #19526 - as can be seen from case 2 there, the validator needs all the members present to find certain errors in multipolygon relations. (Also, the validator needs to run on the relation, first ;)

I mostly work like this: Open a GPX and a number of geotagged photos, then walk the trace and "Download in current view" as I go along. So I come over a number of relations, and as long as I do not touch any of them, no problem. Multipolygons tend to be large and winding and I too rather not have all their members in view from the start, as to stay focused. But I would not mind, if, before uploading I was forced to fetch them, for the validator be get it right. A broken MP, as I have witnessed, can damage the map quite a lot.

[pch14@…]

Looks like 16761/josm fixes this in a better way. Closed by opener.