Merge layer: specific order of layers needed to find conflicts

[skyper]

I found this in #8948, see my comment 3. #8947 was about not finding all conflicts.

What steps will reproduce the problem?

1. open attached file​ (Layer A)
2. select all objects
3. revert selection from changeset 16833418.
4. duplicate layer A (-> Layer B)
5. update data of layer A
   • get 28 conflicts (13 ways, 15 nodes)
6. download the area​ (Layer C)
7. merge layer B on layer C

What is the expected result?

Conflicts after 3. or at least after 7..

What happens instead?

No conflicts and no object is modified after 7.. Changes of layer B are silently dropped.

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

I get only get conflicts with "update data" but there should be conflicts or is this a (new) feature. At least no changes and no conflicts after 7. seems strange.
Merging Layer C on Layer B creates the expected conflicts.

Reverter plugin used to create conflicts but I think it is a new feature if properly documented if it does not.

In my eyes, merging layers needs to create conflicts dependent-less on the order as unlike conflicts with server data both layers can have contradicting changes and both are "my" versions.

I remember to have had similar issues when working offline with small overlapping extracts and then merging several modified extracts before upload.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-10-29 00:51:28 +0100 (Thu, 29 Oct 2020)
Revision:17279
Build-Date:2020-10-29 02:30:54
URL:https://josm.openstreetmap.de/svn/trunk

Plugins:
+ reverter (35579)