[JOSM] "Conflicts when combining ways" becoming annoying

I am tired of having to manually choose which relation to keep, especially when I am merging a freshly created way with no tags or relations into a way that has tags and relations.

How do I get JOSM to automatically merge the ways without forcing me to choose each relation to keep?

How do you merge a way into another one? What command do you use?

I press C to make the existing way absorb the newly-created way, if you get the idea. I am sorry if I sounded frustrated.

Please describe more detailed what you do. C means combine a way with another. What kind of relations are involved?

I’m sorry. Let me try again:

I have been working on administrative boundaries on JOSM. The way I do this is to draw the new boundary as a new way, which by default has no tagging and membership information.

Next, I cut a stub from the way that the new way is replacing, and then connect the stub to the new way, like this:

  S     N

S stands for the stub that has the tagging and relation membership information, and N stands for the new way that I created, which has none.

The expectation is that when I combine the two ways by pressing C, JOSM will automatically keep the tagging and relation membership information of the stub.

The reality is that I get the “Conflicts when combining ways” dialogue, and I have to manually select “keep” for every relation. I thought that it would only be necessary if I was combining two ways that belonged to the same relation, but at different positions (e.g. one way is at position 1 and the other is in position 101).

I can only suggest to do it in a different way: Instead of drawing a new way you can also first cut the existing way and then add new nodes to that way. This works without conflicts.
I’ll try to find out why your way opens the conflict dialog. The same happens when you use Replace Geometry for a way that is member in a relation. My current understanding is that this is not needed when both ways have the same end points.

I looked at this now. I think there is no way to avoid the dialog with your work flow because when you combine the ways you really change the relations, but it should be possible to avoid it when “Replace Geometry” from utilsplugin2 is used like this:
Draw a new way which has the same start and end node as the existing way (and thus the same direction), don’t add any tags.
Select the way to replace and the new way (and nothing else) and use “Replace Geometry” (Shift+Ctrl+G).
In this work flow JOSM can detect that the action doesn’t change the relation(s).
I’ve opened a JOSM ticket with a sample file: https://josm.openstreetmap.de/ticket/17442