Softlock when zooming out quickly with OSMUK cadastral parcels enabled

[robertjwest2002@…]

What steps will reproduce the problem?

1. Download a small area
2. Enable OSMUK Cadastral Parcels
3. Zoom out quickly with the scroll wheel or the View: Zoom to layer hotkey

What is the expected result?

Zooms out without softlocking

What happens instead?

josm softlocks; no buttons or controls work. Windows does not identify the program as 'not responding'.
Unsaved edits are lost if force closing the program with task manager. When I left it running for 30 minutes and a blank error message appeared, I was able to restore the edited data layer next time.

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

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2023-12-07 13:35:12 +0100 (Thu, 07 Dec 2023)
Revision:18907
Build-Date:2023-12-07 16:38:49
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (18907 en_GB) Windows 10 64-Bit
OS Build number: Windows 10 Home 2009 (19045)
Memory Usage: 320 MB / 8176 MB (94 MB allocated, but free)
Java version: 21.0.1+12-LTS, Azul Systems, Inc., OpenJDK 64-Bit Server VM
Look and Feel: com.sun.java.swing.plaf.windows.WindowsLookAndFeel
Screen: \Display0 2560×1440 (scaling 1.00×1.00)
Maximum Screen Size: 2560×1440
Best cursor sizes: 16×16→32×32, 32×32→32×32
System property file.encoding: UTF-8
System property sun.jnu.encoding: Cp1252
Locale info: en_GB
Numbers with default locale: 1234567890 -> 1234567890
VM arguments: [-Dicedtea-web.bin.location=C:\Program Files\OpenWebStart\javaws, -Djava.util.Arrays.useLegacyMergeSort=true, --add-exports=jdk.deploy/com.sun.deploy.config=ALL-UNNAMED, --add-opens=java.desktop/javax.swing.text.html=ALL-UNNAMED, --add-reads=java.naming=ALL-UNNAMED,java.desktop, --add-exports=java.base/sun.security.action=ALL-UNNAMED,java.desktop, --add-reads=java.base=ALL-UNNAMED,java.desktop, --add-exports=java.naming/com.sun.jndi.toolkit.url=ALL-UNNAMED,java.desktop, --add-opens=java.base/jdk.internal.loader=ALL-UNNAMED, --add-exports=java.desktop/com.apple.eawt=ALL-UNNAMED, --add-exports=java.desktop/sun.awt=ALL-UNNAMED,java.desktop, --add-opens=java.base/jdk.internal.ref=ALL-UNNAMED, --add-exports=java.base/sun.security.validator=ALL-UNNAMED,java.desktop, --add-exports=java.desktop/com.sun.imageio.plugins.jpeg=ALL-UNNAMED, --add-exports=java.base/sun.net.www.protocol.jar=ALL-UNNAMED,java.desktop, --add-exports=java.base/jdk.internal.util.jar=ALL-UNNAMED,java.desktop, --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED, --add-exports=java.base/com.sun.net.ssl.internal.ssl=ALL-UNNAMED,java.desktop, --add-exports=javafx.graphics/com.sun.javafx.application=ALL-UNNAMED, --add-modules=java.scripting,java.sql,javafx.controls,javafx.media,javafx.swing,javafx.web, --add-exports=java.desktop/sun.awt.X11=ALL-UNNAMED,java.desktop, --add-exports=java.desktop/sun.applet=ALL-UNNAMED,java.desktop,jdk.jsobject, --add-exports=java.base/sun.net.www.protocol.http=ALL-UNNAMED,java.desktop, --add-opens=java.base/java.lang=ALL-UNNAMED, --add-exports=java.base/sun.security.util=ALL-UNNAMED,java.desktop, --add-exports=java.desktop/com.sun.imageio.spi=ALL-UNNAMED, --add-reads=java.desktop=ALL-UNNAMED,java.naming, --add-opens=java.base/java.nio=ALL-UNNAMED, --add-exports=java.base/sun.security.x509=ALL-UNNAMED,java.desktop, --add-opens=java.desktop/javax.imageio.spi=ALL-UNNAMED, --add-exports=java.desktop/javax.jnlp=ALL-UNNAMED,java.desktop, --add-exports=java.base/sun.security.provider=ALL-UNNAMED,java.desktop, -Djava.security.manager=allow]

Plugins:
+ FastDraw (36126)
+ buildings_tools (36178)
+ imagery_offset_db (36126)
+ jaxb (36118)
+ jogl (1.2.3)
+ kendzi3d-resources (0.0.2)
+ log4j (36176)
+ markseen (14)
+ reltoolbox (36178)
+ reverter (36126)
+ terracer (36181)
+ turnlanes (36126)

Map paint styles:
- https://github.com/bastik/mapcss-tools/raw/osm/mapnik2mapcss/osm-results/mapnik.zip
- https://josm.openstreetmap.de/josmfile?page=Styles/iD&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Enhanced_Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransportV2&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Modified&zip=1

Last errors/warnings:
- 00000.220 W: extended font config - overriding 'filename.Malgun_Gothic=malgun.ttf' with 'MALGUN.TTF'
- 00000.221 W: extended font config - overriding 'filename.Myanmar_Text=mmrtext.ttf' with 'MMRTEXT.TTF'
- 00000.222 W: extended font config - overriding 'filename.Mongolian_Baiti=monbaiti.ttf' with 'MONBAITI.TTF'
- 00002.441 W: Unable to request certificate of https://roottest-g3.pkioverheid.nl
- 00002.825 W: Unable to request certificate of https://roottest-g3.pkioverheid.nl
- 00008.025 W: java.nio.file.FileSystemException: C:\Users\ROBERT~1\AppData\Local\Temp\josm_exec_powershell_7712742894256962271.txt: The process cannot access the file because it is being used by another process
- 00008.025 W: Unable to request certificate of https://grca.nat.gov.tw
- 00013.101 W: java.nio.file.FileSystemException: C:\Users\ROBERT~1\AppData\Local\Temp\josm_exec_powershell_3389053851104870917.txt: The process cannot access the file because it is being used by another process
- 00013.101 W: Unable to request certificate of https://grca.nat.gov.tw

[robertjwest2002@…]

Log

[taylor.smock]

This appears to be due to what is effectively an infinite stream. I'm going to have to debug this a bit to figure out the "best" way to go.
It is effectively a stream of tile positions (0, 0) -> (262143, 262143) at zoom 18, for a total of 68,718,952,449 (68 billion) positions to iterate through. This takes quite a bit of time. Please note that the 262143 were just the first values that I saw exhibit this problem. They changed in subsequent runs.

Now, the reason why this happens is due to an integer overflow problem; the maximum integer (positive) in Java is 2_147_483_647 (2 billion). 68 billion is a _bit_ bigger than 2 billion. When this happens, we have undefined behavior.

I'm strongly inclined to make the modification in JMapViewer instead of JOSM (Math.multiplyExact) and document the ArithmeticException. Alternatively, I can make the change in JOSM and check to see if the value is negative. Having a "too big" number isn't a big issue, since we compare it against the tile cache, which will be _much_ less than 2 billion.

I was able to reliably reproduce, and I suspect I can reproduce with any imagery source that has a min zoom of 18 or higher.

A fairly minimal patch to JOSM would be

core/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java

@@ -1263 +1263 @@
         }
 
         private boolean tooLarge() {
-            return tileCache == null || size() > tileCache.getCacheSize();
+            return tileCache == null || size() > tileCache.getCacheSize() || size() < 0;
         }
 
         /**

I don't like this since there are other locations where size() is called.

[taylor.smock]

In 36198/osm:

See #23367: Give some indication when an integer overflow occurs

In this case, we are throwing an ArithmeticException when an overflow occurs.

[taylor.smock]

In 36199/osm:

Release v2.19: See #23367: Give some indication when an integer overflow occurs in TileRange#size

[taylor.smock]

In 18926/josm:

Fix #23367: Don't try to load too many tiles

In this case, we are catching an ArithmeticException when an integer overflow occurs.

Additionally, fix some lint issues and update some dependencies:

• org.openstreetmap.jmapviewer:jmapviewer: 2.18 -> 2.19
• ch.poole:OpeningHoursParser: 0.27.1 -> 0.28.0
• nl.jqno.equalsverifier:equalsverifier: 3.15.4 -> 3.15.5
• com.google.errorprone:error_prone_core: 2.23.0 -> 2.24.0