Cannot resolve conflict due to this error

[anonymous]

What steps will reproduce the problem?

1. Create a bus line relation with stops and ways
2. Somehow there would be a conflict to resolve
3. Attempt to resolve conflict, get this error

What is the expected result?

Conflict dialog box

What happens instead?

This error

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

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2019-07-10 00:52:47 +0200 (Wed, 10 Jul 2019)
Build-Date:2019-07-10 01:30:51
Revision:15238
Relative:URL: ^/trunk

Identification: JOSM/1.5 (15238 en_CA) Windows 10 64-Bit
OS Build number: Windows 10 Home 1909 (18363)
Memory Usage: 436 MB / 1820 MB (231 MB allocated, but free)
Java version: 1.8.0_221-b11, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: \Display0 1366x768
Maximum Screen Size: 1366x768

Dataset consistency test:
[NO DATASET] {Way id=-242133 version=0 MVT> nodes=[{Node id=3562024025 version=2 V lat=43.9680331,lon=-79.2305878}, {Node id=3562024024 version=2 V lat=43.9679867,lon=-79.2306338}, {Node id=701930313 version=4 V lat=43.9679535,lon=-79.2306441}]} is referenced by {Relation id=6951387 version=24 MVT [node 7876731593, node 3067017518, node 3119011078, node 7618467168, node 2379159916, node 2379159918, node 7879999668, node 2379159924, node 2379159926, node 2379159928, node 2379159930, node 2379159935, node 3119382893, node 7880011433, node 7805152272, node 7880011440, node 7880011442, node 7678083767, node 7880011448, node 7880011449, node 7880080890, node 7880080948, node 7880080973, node 7880080991, node 7880082954, node 7880182718, node 7880082981, node 7880182697, node 7880182726, node 3703077862, node 7880182757, node 7880182758, node 7880182795, node 7880182729, node 7880182698, node 7956020560, node 7956020570, node 7956020588, node 7956020611, node 7956020625, node 7956020645, node 7956020647, node 7959989217, node 7959989232, node 7960012891, node 7960012895, node 7960012918, node 7960012950, node 7960012963, node 7960012976, node 7960013014, node 7960013032, node 3052796534, node 3052795900, node 3054614057, node 7960013140, way 844407427, way 848223470, way 80100960, way 844407426, way 56124637, way 56124735, way 56124641, way 56124631, way 56124662, way 56124679, way 330170296, way 56124699, way 431479278, way 431479279, way 306427552, way 428747951, way 306427551, way 550175696, way 74276701, way 74276696, way 550175695, way 815738692, way 550175898, way 815738696, way 815738693, way 844651530, way 844651531, way 844651532, way 306959599, way 306959597, way 306959596, way 550176319, way 550176320, way 550176687, way 550176684, way 550176686, way 550176413, way 550176414, way 223086969, way 306916082, way 223086968, way 462198306, way 55944741, way 462198302, way 55900511, way 462198299, way 462198305, way 307341383, way 549565692, way 55902629, way 825076739, way 55900363, way 825076740, way 825076736, way 55900781, way 503878456, way 55902615, way 844651566, way 250693250, way 306876863, way 55904392, way 55903166, way 436096576, way 436096577, way 55900503, way 436096578, way 436096579, way 55901481, way 436117320, way 436117318, way 436117324, way 436117319, way 436117323, way 436117317, way 436117322, way 55902746, way 844660248, way 55900916, way 55904356, way 844660261, way 844660258, way 844660259, way 844660271, way 55902022, way 844660272, way 844668636, way 55903784, way 55903580, way 55904425, way 55902748, way 55901685, way 55901807, way 55902698, way 55904425, way 436954073, way 436954789, way 55903153, way 55901190, way 55902993, way 55902474, way 55900744, way 55901757, way 55901824, way 436958496, way 436958495, way 436958494, way 436958493, way 55903259, way 55903747, way 55901516, way 161731000, way 161730998, way 55900492, way 55903086, way 55900744, way 55902474, way 55902993, way 55901190, way -241869, way -241861, way 844668596, way 55901149, way 55901760, way 55900512, way 55902603, way 55903237, way 55901995, way 55904398, way 55903327, way 55902672, way 55900377, way 55900830, way 55903250, way 55902113, way 55902459, way 55901124, way 55904445, way 55900335, way 55902597, way 55904461, way 55903245, way 55901267, way 55903839, way 55900541, way 350456722, way 55900877, way -242133, way 55900538, way 55903431, way 55901664, way 55902330, way 55901806, way 93037468, way 93037608, way 93037584, way 502997258, way 93037592, way 93037598, way 93037581, way 93037464, way 93037635, way 853339429, way 93178961, way 93178933, way 93178940, way 844660274, way 162324653, way 252989053, way 55901518, way 55902614, way 55901588, way 55901144, way 252988907, way 55904319, way 252988906, way 93179642, way 55900925, way 55901362, way 55904491, way 93177982, way -242371]} but not found in dataset


Plugins:
+ measurement (35051)
+ utilsplugin2 (35476)

Last errors/warnings:
- E: Handled by bug report queue: java.lang.IllegalArgumentException: Parameter 'member' must not be null
- E: Handled by bug report queue: java.lang.IllegalArgumentException: Parameter 'member' must not be null
- E: Handled by bug report queue: java.lang.IllegalArgumentException: Parameter 'member' must not be null
- W: Warning - <html>The data to be uploaded participates in pending conflicts of layer 'Data Layer 1'.<br>You have to resolve them first.</html>
- E: Handled by bug report queue: java.lang.IllegalArgumentException: Parameter 'member' must not be null
- E: Handled by bug report queue: java.lang.IllegalArgumentException: Parameter 'member' must not be null
- E: org.openstreetmap.josm.io.IllegalDataException: Relation with external id '6951387' refers to a missing object with external id '-242133'.
- E: Error - <html>Could not read file 'temporary 9th line.osm'.<br>Error is:<br>Relation with external id '6951387' refers to a missing object with external id '-242133'.</html>
- W: Warning - <html>The data to be uploaded participates in pending conflicts of layer 'temporary 9th line.osm'.<br>You have to resolve them first.</html>
- E: Handled by bug report queue: java.lang.IllegalArgumentException: Parameter 'member' must not be null


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

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (17) of main
java.lang.IllegalArgumentException: Parameter 'member' must not be null
	at org.openstreetmap.josm.tools.CheckParameterUtil.ensureParameterNotNull(CheckParameterUtil.java:69)
	at org.openstreetmap.josm.data.osm.RelationMember.<init>(RelationMember.java:85)
	at org.openstreetmap.josm.gui.conflict.pair.relation.RelationMemberListMergeModel.cloneEntryForMergedList(RelationMemberListMergeModel.java:91)
	at org.openstreetmap.josm.gui.conflict.pair.relation.RelationMemberListMergeModel.populate(RelationMemberListMergeModel.java:79)
	at org.openstreetmap.josm.gui.conflict.pair.relation.RelationMemberMerger.populate(RelationMemberMerger.java:64)
	at org.openstreetmap.josm.gui.conflict.pair.ConflictResolver.populate(ConflictResolver.java:258)
	at org.openstreetmap.josm.gui.dialogs.ConflictDialog.resolve(ConflictDialog.java:207)
	at org.openstreetmap.josm.gui.dialogs.ConflictDialog.access$200(ConflictDialog.java:78)
	at org.openstreetmap.josm.gui.dialogs.ConflictDialog$ResolveAction.actionPerformed(ConflictDialog.java:466)
	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
	at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
	at java.awt.Component.processMouseEvent(Unknown Source)
	at javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.awt.Component.processEvent(Unknown Source)
	at java.awt.Container.processEvent(Unknown Source)
	at java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.awt.EventQueue.access$500(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue$4.run(Unknown Source)
	at java.awt.EventQueue$4.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)

[GerdP]

Please update JOSM, your version is more than a year old.

[Don-vip]

As your version of Java.