[regression] Combine Way creates invalid way

[Aurimas]

What steps will reproduce the problem?

1. Open combine_way.osm – two relations share one duplicated way.
2. Validate (Shift + V).
3. Validator shows an error "Duplicated ways (1)".
4. Select both ways and use "Combine way" (C).
5. Resolve a conflict by selecting "Keep" for both relations.

What is the expected result?

Ways are combined into one valid way (combine_expected.osm). No validation errors.

What happens instead?

Combined way is invalid. Validator shows 3 errors and one warning:

• Multipolygon is not closed (2)
• Way contains segment twice (1)
• Self-intersecting ways (1)

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

Started to happen sometime around 15558/josm.

[stoecker]

That's wanted behavior. Combine way ONLY combines the way without changing the geometry. As far as I remember you get a notice when the combination result creates data which is unwanted in OSM database and needs further modifications.

Also your description is strange. Calling Combine way for a duplicate way is completely wrong. Combine way is a tool to join multiple split segments of one way into one way.

It's not the correct tool to join identical ways into one.

[Aurimas]

Replying to stoecker:

It's not the correct tool to join identical ways into one.

What is a correct tool to joint identical ways into one?

[stoecker]

Add one of the lines to the second relation and delete the other line.

[Aurimas]

Replying to stoecker:

Add one of the lines to the second relation and delete the other line.

Then it's not a tool, but a workaround with many slow and error prone steps.
Especially if one or both ways are shared by more than 2 relations (quite common for administrative relations).

With "Combine way" it was possible to accomplish this task with two simple and fast steps:

1. Select both ways (manually or from validator results) and use "Combine way" (C).
2. Resolve a conflict by selecting "Keep" for both relations.

It is still possible to accomplish this task with "Combine way", but it now takes more steps (however, still faster than manual relation editing):

1. Select both ways (manually or from validator results) and use "Combine way" (C).
2. Resolve a conflict by selecting "Keep" for both relations.
3. Additionally select both ends of the invalid way.
4. "Split way" (P).
5. Select one of the resulting two ways.
6. Delete it.

[skyper]

Using "copy relation memberships" from utilsplugin2 and then deleting is faster but sadly the order is not preserved.

[skyper]

Is there a reason, to have "combine ways" create invalid ways using a way segment multiple times? I think it would be smarter to automatically remove all but one of the duplicate segments at least if it is at one end of the way.

[stoecker]

Replying to Aurimas:

Replying to stoecker:

Add one of the lines to the second relation and delete the other line.

Then it's not a tool, but a workaround with many slow and error prone steps.
Especially if one or both ways are shared by more than 2 relations (quite common for administrative relations).

Two steps are "many slow and error prone"?

[stoecker]

Replying to skyper:

Is there a reason, to have "combine ways" create invalid ways using a way segment multiple times? I think it would be smarter to automatically remove all but one of the duplicate segments at least if it is at one end of the way.

See the corresponding tickets for the rationale.

[Aurimas]

Replying to stoecker:

Replying to Aurimas:

Replying to stoecker:

Add one of the lines to the second relation and delete the other line.

Then it's not a tool, but a workaround with many slow and error prone steps.
Especially if one or both ways are shared by more than 2 relations (quite common for administrative relations).

Two steps are "many slow and error prone"?

Could you spell out these two steps.
I tried, but could not perform "Add one of the lines to the second relation and delete the other line" in less than ~10 steps.