Conflation Error with LineString

[taylor.smock]

What steps will reproduce the problem?

1. Download the Incorporated Areas shapefile at ​https://emap.mesacounty.us/DownloadData/
2. Download the boundaries for Grand Junction, Colorado (I used overpass api with boundary=administrative)
3. Attempt to conflate the (newer) boundaries for Grand Junction onto the older boundary (by selecting the ways in the relation)

What is the expected result?

1. Either no crash or conflation

What happens instead?

Crash

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

Note: The screenshot has one node in the subject dataset, the issue still occurs without the node selected

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2018-12-31 15:09:58 +0100 (Mon, 31 Dec 2018)
Build-Date:2018-12-31 14:24:10
Revision:14620
Relative:URL: ^/trunk

Identification: JOSM/1.5 (14620 en) Linux Fedora release 29 (Twenty Nine)
Memory Usage: 918 MB / 1820 MB (459 MB allocated, but free)
Java version: 1.8.0_191-b13, Oracle Corporation, OpenJDK 64-Bit Server VM
Screen: :0.0 1440x900, :0.1 1280x1024
Maximum Screen Size: 1440x1024
Java package: java-1.8.0-openjdk:x86_64-1.8.0.191.b13
WebStart package: icedtea-web:noarch-1.7.1
VM arguments: [-Dicedtea-web.bin.name=javaws.itweb, -Dicedtea-web.bin.location=/usr/bin/javaws.itweb]
Dataset consistency test: No problems found

Plugins:
+ Mapillary (v1.5.17)
+ OpenStreetCam (183)
+ apache-commons (34506)
+ apache-http (34632)
+ buildings_tools (34724)
+ conflation (0.6.2)
+ continuosDownload (82)
+ ejml (34389)
+ geotools (34513)
+ graphview (34576)
+ imagery_offset_db (34641)
+ jaxb (34506)
+ jna (34633)
+ jogl (1.2.2)
+ jts (34524)
+ kendzi3d (1.0.205)
+ kendzi3d-resources (0.0.2)
+ log4j (34527)
+ opendata (34805)
+ pt_assistant (2.1.10)
+ utilsplugin2 (34793)
+ wikipedia (v1.1.1)

Tagging presets:
+ http://zibi.openstreetmap.org.pl/kendzi/k/Simple3dPreset/s3db-preset.zip
+ https://josm.openstreetmap.de/josmfile?page=Presets/caravan_site&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/contact(socialnetworks_IMs)&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Healthcare&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/ParkingLanes&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Playground_Equipment&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Simple_Indoor_Tagging&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Surveillance&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/WifiHotspots&zip=1

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/Fixme&zip=1
+ https://github.com/osmlab/appledata/archive/josm_paint_inline_validation.zip
+ https://josm.openstreetmap.de/josmfile?page=Styles/AddressValidator&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Lane_and_Road_Attributes&zip=1
+ https://raw.githubusercontent.com/species/josm-preset-traffic_sign_direction/master/direction.mapcss
- https://www.dropbox.com/s/qo3ai47fpv241jf/Styles_Fixme_and_Notes.zip?raw=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/Schools&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransportV2&zip=1
- https://raw.githubusercontent.com/OpenSidewalks/OpenSidewalks-Schema/master/open_sidewalks.mapcss
- https://github.com/GlassOceanos/indoor-JOSM-style/archive/master.zip
- ${HOME}/Downloads/Kaart_Styles_3.1.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransport&zip=1

Validator rules:
+ ${HOME}/Downloads/osm/hydrant_validation.validator.mapcss
+ https://raw.githubusercontent.com/taylorsmock/KaartValidator/master/kaart.validator.mapcss

Last errors/warnings:
- W: No configuration settings found.  Using hardcoded default values for all pools.
- W: Expecting test 'The US flow rate is usually usgal/min' (i.e., [*[emergency=fire_hydrant][flow_rate'REGEX'^(\d*.\d*|\d*)$][ParameterFunction~inside(class org.openstreetmap.josm.gui.mappaint.Environment,class java.lang.String <US>)]]) to match node emergency=fire_hydrant flow_rate=24000 (i.e., TagMap[flow_rate=24000,emergency=fire_hydrant])
- W: Expecting test 'The US flow rate is usgal/min -- please check the units' (i.e., [*[emergency=fire_hydrant][flow_rate][flow_rate'NREGEX'^(\d*|\d*.\d*|.*usgal\/min)$][ParameterFunction~inside(class org.openstreetmap.josm.gui.mappaint.Environment,class java.lang.String <US>)]]) to match node emergency=fire_hydrant flow_rate="24000 gal/min" (i.e., TagMap[flow_rate=24000 gal/min,emergency=fire_hydrant])
- W: Expecting test 'The US flow rate is usgal/min -- please check the units' (i.e., [*[emergency=fire_hydrant][flow_rate][flow_rate'NREGEX'^(\d*|\d*.\d*|.*usgal\/min)$][ParameterFunction~inside(class org.openstreetmap.josm.gui.mappaint.Environment,class java.lang.String <US>)]]) to match node emergency=fire_hydrant flow_rate=24000 (i.e., TagMap[flow_rate=24000,emergency=fire_hydrant])
- W: couldn't parse wizard input
- E: org.openstreetmap.josm.tools.UncheckedParseException
- E: null is NOT valid
- E: Reason: cvc-elt.1: Cannot find the declaration of element 'metadata'.
- E: Handled by bug report queue: java.lang.IllegalArgumentException: Invalid number of points in LineString (found 1 - must be 0 or >= 2)


=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-1 (23) of JOSM
java.lang.IllegalArgumentException: Invalid number of points in LineString (found 1 - must be 0 or >= 2)
	at com.vividsolutions.jts.geom.LineString.init(LineString.java:102)
	at com.vividsolutions.jts.geom.LineString.<init>(LineString.java:93)
	at org.openstreetmap.josm.plugins.jts.JTSConverter.convertWay(JTSConverter.java:97)
	at org.openstreetmap.josm.plugins.jts.JTSConverter.convert(JTSConverter.java:105)
	at org.openstreetmap.josm.plugins.conflation.OsmFeature.<init>(OsmFeature.java:37)
	at org.openstreetmap.josm.plugins.conflation.MatchesComputation.createFeatureCollection(MatchesComputation.java:119)
	at org.openstreetmap.josm.plugins.conflation.MatchesComputation.generateMatches(MatchesComputation.java:48)
	at org.openstreetmap.josm.plugins.conflation.ConflationToggleDialog$2.realRun(ConflationToggleDialog.java:1147)
	at org.openstreetmap.josm.gui.PleaseWaitRunnable.doRealRun(PleaseWaitRunnable.java:95)
	at org.openstreetmap.josm.gui.PleaseWaitRunnable.run(PleaseWaitRunnable.java:143)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)