[josm-dev] How to resolve conflicts?

[Dirk Stöcker]

On Mon, 19 Jul 2010, M∡rtin Koppenhoefer wrote:

> As it seems that recent JOSMs contain a severe bug for conflict
> handling, which is the suggested way to avoid duplicate nodes and
> ways? Usually this gets preceded by an error during upload with the
> question: do you want to
> a) synchronize the (way/node) only
> b) synchronize the whole data set
> c) cancel
>
> Which is the right answer to click in order to minimize conflicts?
> What steps should be done afterwards?
> related information here:
> http://josm.openstreetmap.de/ticket/5215

JOSM never had a detection to find that new elements in editor are equal 
to elements on the database. As soon as upload went well for the server, 
but josm doen't get informed about there is a problem.

We don't have a "match new stuff to server stuff and drop it when equal". 
This would be required to fix this issue.

Mainly it is caused by missing transaction security of the API. In the 
past when only one single element was uploaded at once it was not as 
obvious as it is now.

What to do: When you have this situation that upload may have aborted 
after the elements got accepted by server:

- Download the same area in a new layer.
- Check if your changes exist there as well.
   Yes: Drop the layer with the original changes.
   No:  Upload again, as first upload failed.

There is no need to use JOSM conflict resolution at all. It can't handle 
these cases.

If this happens to you more often: Do smaller changesets. The issue 
probably appears when server needs to long for validity checking and a 
timeout catches. Smaller changesets will reduce that problem.

Ciao
-- 
http://www.dstoecker.eu/ (PGP key available)