Sort relation's member: Better protection of incomplete relations.

[skyper]

What steps will reproduce the problem?

1. Open an incomplete (route) relation in relation editor with only some downloaded members
2. (Select first member)
3. click on "Sort the relation's members" or "Sort the selected relation's members and everything below"

What is the expected result?

A warning asking if I want to (completely) sort a relation with incomplete members. With options to save answer as usual.

What happens instead?

No warning and order of relation is destroyed as the downloaded members are sorted on top

Please provide any additional information below. Attach a screenshot if possible.

Not sure how to proper handle the situation because denying sorting on incomplete relations is too restrictive.

1. Members object type way should not be sorted at all if no connection is possible
2. Members object type way should not be sorted to a lower numbered position than the lowest numbered position of a complete member with object type way

My most distracting user fault, modifying relations and their order is unintentional sorting with only one member instead of a handful spread somewhere selected. In my editing scenarios, I would love to get the warning represented even with complete relations and "Sort the relation`s members". At least for route relations it would help me and not distract much.

In my eyes, it could be made more difficult to unintentionally, completely sort (route) relations by downgrading "Sort the relation's members" to "Sort the selected relation's members" and making "Sort the selected relation`s members and everything below" available in normal mode.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-04-06 02:17:07 +0200 (Mon, 06 Apr 2020)
Revision:16239
Build-Date:2020-04-06 00:18:43
URL:https://josm.openstreetmap.de/svn/trunk

[skyper]

Maybe, it is easier too disable most of sorting of incomplete relations, see #20643.