"Update multipolygon" strips natural=coastline from member ways

[DoctorSpeck]

What steps will reproduce the problem?

1. download map data that has a water or wetland multipolygon that has member ways tagged with natural=coastline ex: ​https://www.openstreetmap.org/relation/8246560
2. draw a new way that will become an inner way
3. select the relation by holding shift and double clicking in the multipolygon
4. update the multipolygon using the "update multipolygon" tool (ctrl+shift+B on windows).
5. observe that natural=coastline has been stripped from member ways

What is the expected result?

the new feature will be added to the multipolygon with appropriate inner/outer roles, and existing member ways retain their previous tagging ie. natural=coastline

What happens instead?

any member ways that have natural=coastline individually tagged, will be stripped after the "update multipolygon" command.

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

Sparse editing can cause broken coastline as the user may not be notified of a broken coastline if adjacent coastline segments are not downloaded (it will pass verification checks). This leaves the user to try to remember where the coastline was previously or inadvertently break coastline continuity.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-10-03 13:42:38 +0200 (Sat, 03 Oct 2020)
Revision:17084
Build-Date:2020-10-04 01:30:47
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (17084 en) Windows 10 64-Bit
OS Build number: Windows 10 Pro 2009 (19042)
Memory Usage: 1936 MB / 4096 MB (1346 MB allocated, but free)
Java version: 11.0.8+10, AdoptOpenJDK, OpenJDK 64-Bit Server VM
Look and Feel: com.sun.java.swing.plaf.windows.WindowsLookAndFeel
Screen: \Display0 1920x1200 (scaling 1.0x1.0), \Display1 1680x1050 (scaling 1.0x1.0), \Display2 1680x1050 (scaling 1.0x1.0)
Maximum Screen Size: 1920x1200
Best cursor sizes: 16x16 -> 32x32, 32x32 -> 32x32

Plugins:
+ BuildingGeneralization (23)
+ CADTools (1008)
+ CommandLine (35583)
+ EasyPresets (1604762161)
+ FastDraw (35499)
+ ImproveWay (29)
+ RelationDissolve (0.2.0)
+ RoadSigns (35510)
+ ShapeTools (1240)
+ SimplifyArea (35579)
+ alignways (35583)
+ apache-commons (35524)
+ apache-http (35092)
+ auto_tools (73)
+ buildings_tools (35579)
+ conflation (0.6.6)
+ ejml (35313)
+ ext_tools (35499)
+ flatlaf (35572)
+ geotools (35169)
+ imagery_offset_db (35405)
+ jaxb (35092)
+ jna (35092)
+ jts (35122)
+ mapwithai (1.7.0)
+ measurement (35579)
+ opendata (35513)
+ reltoolbox (35602)
+ reverter (35638)
+ strava_heatmap (1.0)
+ tageditor (35258)
+ terracer (35579)
+ todo (30306)
+ turnlanes (35405)
+ turnlanes-tagging (288)
+ turnrestrictions (35583)
+ utilsplugin2 (35624)
+ wikipedia (1.1.4)

Tagging presets:
+ https://raw.githubusercontent.com/OpenNauticalChart/josm/master/Presets_Hafen.xml
+ https://josm.openstreetmap.de/josmfile?page=Presets/Historical_Objects&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Industrial&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/LaneAttributes&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/ParkingLanes&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Playground_Equipment&zip=1
+ https://raw.githubusercontent.com/yopaseopor/traffic_signs_preset_JOSM/master/US.zip
+ https://josm.openstreetmap.de/josmfile?page=Presets/BuildingPreset&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Community_Centre&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Disc_Golf_Course&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Golf_Course&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Heritage&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/hiking_routes_with_trail_marking&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Maxspeed-zones&zip=1
+ https://raw.githubusercontent.com/OpenNauticalChart/josm/master/INT-1-preset.xml
+ https://josm.openstreetmap.de/josmfile?page=Presets/OpenSeaMap-PresetForSeamarks&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/AdvertisingPreset&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Camp_site_extends&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Healthcare&zip=1
+ https://raw.githubusercontent.com/osmlab/name-suggestion-index/master/dist/name-suggestions.presets.xml
+ https://josm.openstreetmap.de/josmfile?page=Presets/NewTags&zip=1
+ https://raw.githubusercontent.com/species/josm-preset-wheelchair/master/sidewalks_kerbs.xml
+ https://josm.openstreetmap.de/josmfile?page=Presets/OneClick&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/MastAndTower&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/TurnLanes&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/OpenSeaMap_bridge&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Mountains&zip=1

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/Modified&zip=1
+ https://pasharm.github.io/New_basic_style_for_JOSM/New_basic_style.mapcss
- https://github.com/bastik/mapcss-tools/raw/osm/mapnik2mapcss/osm-results/mapnik.zip
- http://kolesar.turistautak.hu/osm/opencellid/api/styles/measurements.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/Schools&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Sidewalks&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Cycleways&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Enhanced_Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Incline&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Lane_features&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Lane_features_ryg&zip=1
- https://raw.githubusercontent.com/OpenSidewalks/OpenSidewalks-Schema/master/open_sidewalks.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/ParkingLanes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Bench&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Admin_Boundaries&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Landcover&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Maxspeed&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/TigerReviewedNo&zip=1
- https://github.com/hotosm/HDM-JOSM-style/archive/master.zip
- https://josm.openstreetmap.de/josmfile?page=Styles/MapWithAI&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/IconTester&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/iD&zip=1
- https://github.com/osmlab/appledata/archive/josm_paint_inline_validation.zip
- https://josm.openstreetmap.de/josmfile?page=Styles/Surface&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Styles/HiDPISupport&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Surface-DataEntry&zip=1
- https://github.com/gmgeo/osmic-josm-style/archive/master.zip
- https://josm.openstreetmap.de/josmfile?page=Styles/Mountains&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/LayerChecker&zip=1
- https://www.openrailwaymap.org/styles/josm-additional.zip
- https://www.openrailwaymap.org/styles/standard.zip

Last errors/warnings:
- 00001.427 W: extended font config - overriding 'filename.Myanmar_Text=mmrtext.ttf' with 'MMRTEXT.TTF'
- 00001.427 W: extended font config - overriding 'filename.Mongolian_Baiti=monbaiti.ttf' with 'MONBAITI.TTF'
- 00009.810 W: Failed to delete outdated plugin '<josm.pref>\plugins\flatlaf.jar'.
- 00009.810 W: Failed to install already downloaded plugin 'flatlaf'. Skipping installation. JOSM is still going to load the old plugin version.
- 00015.541 W: java.io.IOException: The requested URL http://kolesar.turistautak.hu/osm/opencellid/api/styles/measurements.mapcss was not found
- 00016.929 W: Failed to load Mappaint styles from 'http://kolesar.turistautak.hu/osm/opencellid/api/styles/measurements.mapcss'. Exception was: java.io.IOException: The requested URL http://kolesar.turistautak.hu/osm/opencellid/api/styles/measurements.mapcss was not found
- 00016.929 E: java.io.IOException: The requested URL http://kolesar.turistautak.hu/osm/opencellid/api/styles/measurements.mapcss was not found
- 00021.131 W: javax.imageio.IIOException: Caught exception during read:. Cause: java.lang.ArrayIndexOutOfBoundsException: Index 1 out of bounds for length 1
- 00021.131 E: Failed to locate image 'traffic_signs_presets/tunnel.png'
- 00021.131 W:  Tunnel: Could not get presets icon traffic_signs_presets/tunnel.png

[GerdP]

This also happens if you just select a way of the multipolygon and use ctrl+shift+B to update. There is code to prevent this but it doesn't seem to work.

[GerdP]

@Zverikk: For r5225 the problematic code was copied from Reltoolbox plugin.
The following small patch fixes the problem in this ticket and passes all unit tests in CreateMultipolygonActionTest

src/org/openstreetmap/josm/actions/CreateMultipolygonAction.java

@@ -416 +416 @@
                 for (String key : way.keySet()) {
                     if (!values.containsKey(key)) { //relation values take precedence
                         values.put(key, way.get(key));
-                    } else if (!relation.hasKey(key) && !values.get(key).equals(way.get(key))) {
+                    } else if (!values.get(key).equals(way.get(key))) {
                         conflictingKeys.add(key);
                     }
                 }

Do you remember why you added "!relation.hasKey(key)"?
Similar code exists in the block following the comment

filter out empty key conflicts - we need second iteration

I don't understand what this block is about. Is it even possible to have empty keys?

[GerdP]

patch and unit test

[Don-vip]

Milestone renamed

[GerdP]

In 17343/josm:

fix #20110: "Update multipolygon" strips natural=coastline from member ways

• fix and unit test