When I attempt to use a custom image tile server, JOSM crashes

[anonymous]

What steps will reproduce the problem?

1. add a custom web tile image source, such as ​https://c.sm.mapstack.stamen.com/(terrain-background,watercolor[overlay@50])/{z}/{x}/{y}.png

What is the expected result?

JOSM loads the map source as a layer, or fails to fetch but remains responsive.

What happens instead?

JSOM crashes

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

Revision:18678
Build-Date:2023-03-02 13:38:01

Identification: JOSM/1.5 (18678 en) Mac OS X 10.15.7
OS Build number: Mac OS X 10.15.7 (19H2026)
Memory Usage: 2048 MB / 2048 MB (97 MB allocated, but free)
Java version: 17.0.6+10-LTS, Azul Systems, Inc., OpenJDK 64-Bit Server VM
Look and Feel: com.apple.laf.AquaLookAndFeel
Screen: Display 69677248 1280×800 (scaling 1.00×1.00)
Maximum Screen Size: 1280×800
Best cursor sizes: 16×16→16×16, 32×32→32×32
System property file.encoding: UTF-8
System property sun.jnu.encoding: UTF-8
Locale info: en_US
Numbers with default locale: 1234567890 -> 1234567890
VM arguments: [-Djpackage.app-version=18678, --add-modules=java.scripting,java.sql,javafx.controls,javafx.media,javafx.swing,javafx.web, --add-exports=java.base/sun.security.action=ALL-UNNAMED, --add-exports=java.desktop/com.apple.eawt=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.plugins.jpeg=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.spi=ALL-UNNAMED, --add-opens=java.base/java.lang=ALL-UNNAMED, --add-opens=java.base/java.nio=ALL-UNNAMED, --add-opens=java.base/jdk.internal.loader=ALL-UNNAMED, --add-opens=java.base/jdk.internal.ref=ALL-UNNAMED, --add-opens=java.desktop/javax.imageio.spi=ALL-UNNAMED, --add-opens=java.desktop/javax.swing.text.html=ALL-UNNAMED, --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED, -Djpackage.app-path=/Applications/JOSM.app/Contents/MacOS/JOSM]
Dataset consistency test: No problems found

Map paint styles:
+ https://josm.openstreetmap.de/josmfile?page=Styles/Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/MapillaryDetections&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransportV2&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Styles/SidewalksAndFootways&zip=1

Last errors/warnings:
- 00101.390 E: Handled by bug report queue: java.lang.IllegalArgumentException: Vector tile layers must have a layer name
- 00101.446 E: Handled by bug report queue: java.lang.IllegalArgumentException: Unknown field in vector tile layer value (31)
- 00101.496 E: Handled by bug report queue: java.lang.IllegalArgumentException: Vector tile layers must have a layer name
- 00101.496 W: Too many errors. Dropping ReportedException [thread=Thread[MVT-downloader-34,5,main], exception=java.lang.IllegalArgumentException: Vector tile layers must have a layer name, methodWarningFrom=BugReportExceptionHandler#handleException]
- 00101.539 E: Handled by bug report queue: java.lang.IllegalArgumentException: Vector tile layers must have a layer name
- 00101.539 W: Too many errors. Dropping ReportedException [thread=Thread[MVT-downloader-20,5,main], exception=java.lang.IllegalArgumentException: Vector tile layers must have a layer name, methodWarningFrom=BugReportExceptionHandler#handleException]
- 00101.591 E: Handled by bug report queue: java.lang.IllegalArgumentException: Vector tile layers must have a layer name
- 00101.591 W: Too many errors. Dropping ReportedException [thread=Thread[MVT-downloader-33,5,main], exception=java.lang.IllegalArgumentException: Vector tile layers must have a layer name, methodWarningFrom=BugReportExceptionHandler#handleException]
- 00102.762 E: Handled by bug report queue: java.lang.OutOfMemoryError: Java heap space
- 00103.401 E: Handled by bug report queue: java.lang.OutOfMemoryError: Java heap space



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

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: MVT-downloader-14 (109)
java.lang.NegativeArraySizeException: -85445818
	at org.openstreetmap.josm.data.protobuf.ProtobufParser.readNextBytes(ProtobufParser.java:243)
	at org.openstreetmap.josm.data.protobuf.ProtobufParser.nextLengthDelimited(ProtobufParser.java:207)
	at org.openstreetmap.josm.data.protobuf.ProtobufRecord.<init>(ProtobufRecord.java:53)
	at org.openstreetmap.josm.data.protobuf.ProtobufParser.allRecords(ProtobufParser.java:126)
	at org.openstreetmap.josm.data.imagery.vectortile.mapbox.MVTTile.loadImage(MVTTile.java:54)
	at org.openstreetmap.josm.data.imagery.TMSCachedTileLoaderJob.tryLoadTileImage(TMSCachedTileLoaderJob.java:328)
	at org.openstreetmap.josm.data.imagery.TMSCachedTileLoaderJob.loadingFinished(TMSCachedTileLoaderJob.java:210)
	at org.openstreetmap.josm.data.cache.JCSCachedTileLoaderJob.finishLoading(JCSCachedTileLoaderJob.java:265)
	at org.openstreetmap.josm.data.cache.JCSCachedTileLoaderJob.run(JCSCachedTileLoaderJob.java:234)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)

[taylor.smock]

@anonymous: A good first step would be to use the correct imagery type. We can probably work around the crash and show a semi-intelligent message to the user.