Complain about free-floating building:part

[mkoniecz]

What steps will reproduce the problem?

1. Create a closed way
2. Tag it with building:part=yes
3. Unselect it
4. Run validator

What is the expected result?

Validator complains about building:part that is not inside any building area.

What happens instead?

Nothing.

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

Triggered by ​https://github.com/westnordost/StreetComplete/issues/1858

I suspect that it may be impossible due to performance issues.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-05-18 09:57:52 +0200 (Mon, 18 May 2020)
Revision:16460
Build-Date:2020-05-19 01:30:51
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (16460 en_GB) Linux Ubuntu 19.10
Memory Usage: 263 MB / 976 MB (151 MB allocated, but free)
Java version: 11.0.7+10-post-Ubuntu-2ubuntu219.10, Ubuntu, OpenJDK 64-Bit Server VM
Screen: :0.0 1920x1080
Maximum Screen Size: 1920x1080
Java package: openjdk-11-jre:amd64-11.0.7+10-2ubuntu2~19.10
Java ATK Wrapper package: libatk-wrapper-java:all-0.35.0-3
libcommons-logging-java: libcommons-logging-java:all-1.2-2
fonts-noto: fonts-noto:-
Dataset consistency test: No problems found

Plugins:
+ buildings_tools (35405)
+ measurement (35405)
+ reverter (35409)

[GerdP]

The wiki (1) seems to allow this when the building:part area is member of a type=building relation?
(1) ​https://wiki.openstreetmap.org/wiki/Simple_3D_buildings#Building_parts

[mkoniecz]

requiring type=building anyway indirectly requires building area:

​https://wiki.openstreetmap.org/wiki/Relation:building

"outline one or more The area that makes up the building outline, e.g. the walls. This outline needs to be tagged with Tag:building=yes or another building value for compatibility with 2D-renderers. "

[GerdP]

I meant this sentence:
"The building parts can be located in any possible way (inside, outside, intersecting, touching) relative to the building outline in the presence of the type=building relation."
​https://wiki.openstreetmap.org/wiki/Simple_3D_buildings#Building_relations

[mkoniecz]

No idea what is being proposed there. I posted ​https://wiki.openstreetmap.org/wiki/Talk:Simple_3D_buildings#building_part_outside_outline

[GerdP]

What about the sample given in the wiki?
​https://wiki.openstreetmap.org/wiki/File:Minlevel.svg
I think the middle is outside.

[mkoniecz]

I would map it with middle inside. Maybe overhangs would qualify as the intended example? For example a micromapped roof, starting 30cm outside of walls. Or underground extension would qualify?

Still, min_height, building:min_Level location=undeground exceptions should be sufficient to have only valid reports.