NullPointerException when editing mapcss validator rules with invalid pseudo class

[Famlam]

What steps will reproduce the problem?

1. Open JOSM on any area
2. Add a custom validator mapcss file (prefs -> validator -> second tab -> add a local file ending on .validator.mapcss)
3. Edit this *.validator.mapcss file (and save) to contain a rule, i.e. add:

   node["traffic_signals:direction"]:connection {
     group: tr("eigen filters");
   	throwWarning: tr("Node met {0} op een kruising van meerdere wegen", "{0.key}");
   }
   

4. Then modify the file to something containing a non-existent pseudo class selector (for example due to a typo, or just being used to press ctrl-S often, or have some autosave on, or ...)

   node["traffic_signals:direction"]:connection:downloaded {
     group: tr("eigen filters");
   	throwWarning: tr("Node met {0} op een kruising van meerdere wegen", "{0.key}");
   }
   

5. Save again. JOSM will crash.

(Note that it does show a warning when initializing JOSM; only when JOSM is already open it really crashes)

What is the expected result?

No crash (maybe a warning)

What happens instead?

Crash

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: 2020-07-30 12:44:04 +0200 (Thu, 30 Jul 2020)
Build-Date:2020-07-31 01:30:49
Revision:16812
Relative:URL: ^/trunk

Identification: JOSM/1.5 (16812 nl) Windows 10 64-Bit
OS Build number: Windows 10 Home 2004 (19041)
Memory Usage: 766 MB / 1820 MB (371 MB allocated, but free)
Java version: 1.8.0_261-b12, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Look and Feel: com.sun.java.swing.plaf.windows.WindowsLookAndFeel
Screen: \Display0 1920x1080 (scaling 1.0x1.0)
Maximum Screen Size: 1920x1080
Best cursor sizes: 16x16 -> 32x32, 32x32 -> 32x32
Dataset consistency test: No problems found

Plugins:
+ OpeningHoursEditor (35414)
+ imagery_offset_db (35405)
+ pt_assistant (2.1.10-80-g7d9bba3)
+ tageditor (35258)
+ turnlanes-tagging (283)
+ undelete (35499)
+ utilsplugin2 (35487)

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

Validator rules:
+ %UserProfile%\Documents\tijdelijke bestanden\josm-eigen.validator.mapcss

Last errors/warnings:
- W: java.net.SocketTimeoutException: Read timed out
- W: java.net.SocketTimeoutException: Read timed out
- W: java.net.SocketTimeoutException: Read timed out
- W: java.net.SocketTimeoutException: Read timed out
- W: java.net.SocketTimeoutException: Read timed out
- W: java.net.SocketTimeoutException: Read timed out
- E: Skipping to the next rule, because of an error:
- E: org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.ParseException: Encountered " "<" "< "" at line 270, column 59.
- E: org.openstreetmap.josm.gui.mappaint.mapcss.MapCSSException: Invalid pseudo class specified: downloaded
- E: Handled by bug report queue: java.lang.NullPointerException


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

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: File Watcher (24)
java.lang.NullPointerException
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.ParseException.initialise(ParseException.java:125)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.ParseException.<init>(ParseException.java:39)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.generateParseException(MapCSSParser.java:3725)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.error_skipto(MapCSSParser.java:2184)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.sheet(MapCSSParser.java:893)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker$TagCheck.readMapCSS(MapCSSTagChecker.java:359)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.addMapCSS(MapCSSTagChecker.java:790)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.addMapCSS(MapCSSTagChecker.java:778)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.reloadRule(MapCSSTagChecker.java:858)
	at org.openstreetmap.josm.io.FileWatcher.processEvents(FileWatcher.java:160)
	at java.lang.Thread.run(Unknown Source)

[skyper]

This exception does not harm a lot but can get annoying . Only auto load function does not work after it. So you need either to manually load changed rules or restart JOSM.

[skyper]

Similar to #19503.

[Famlam]

Perhaps it's advisable to run the auto-load functionality only when (the file has changed and) JOSM actually gets the focus (or better: is about to run the validator)

Warning or error: both are not that useful when you're in your text editor and JOSM is somewhere in the background. They only become useful when you actually want to use the file with rules.

(If so, I guess I should file this as a separate issue, or not?)

[skyper]

It simply should produce warnings like in other cases and not through exceptions. I like the autoload function and as long as you get the warnings only on the console there is no problem.

[simon04]

Full stack trace (in particular with ​JEP 358: Helpful NullPointerExceptions from Java 14)

2020-08-23 11:39:16.935 INFO: Source x.validator.mapcss has been modified. Reloading it...
2020-08-23 11:39:16.938 SEVERE: org.openstreetmap.josm.gui.mappaint.mapcss.MapCSSException: Invalid pseudo class specified: xxx
org.openstreetmap.josm.gui.mappaint.mapcss.MapCSSException: Invalid pseudo class specified: xxx
	at org.openstreetmap.josm.gui.mappaint.mapcss.ConditionFactory$PseudoClassCondition.createPseudoClassCondition(ConditionFactory.java:825)
	at org.openstreetmap.josm.gui.mappaint.mapcss.ConditionFactory.createPseudoClassCondition(ConditionFactory.java:128)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.class_or_pseudoclass(MapCSSParser.java:1545)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.selector(MapCSSParser.java:1129)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.child_selector(MapCSSParser.java:948)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.selectors(MapCSSParser.java:920)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.rule(MapCSSParser.java:905)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.sheet(MapCSSParser.java:889)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker$TagCheck.readMapCSS(MapCSSTagChecker.java:359)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.addMapCSS(MapCSSTagChecker.java:790)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.addMapCSS(MapCSSTagChecker.java:778)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.reloadRule(MapCSSTagChecker.java:858)
	at org.openstreetmap.josm.io.FileWatcher.processEvents(FileWatcher.java:160)
	at java.base/java.lang.Thread.run(Thread.java:834)

2020-08-23 11:39:16.947 SEVERE: Handled by bug report queue: java.lang.NullPointerException
java.lang.NullPointerException: Cannot read field "beginLine" because "currentToken.next" is null
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.ParseException.initialise(ParseException.java:125)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.ParseException.<init>(ParseException.java:39)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.generateParseException(MapCSSParser.java:3725)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.error_skipto(MapCSSParser.java:2184)
	at org.openstreetmap.josm.gui.mappaint.mapcss.parsergen.MapCSSParser.sheet(MapCSSParser.java:893)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker$TagCheck.readMapCSS(MapCSSTagChecker.java:359)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.addMapCSS(MapCSSTagChecker.java:790)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.addMapCSS(MapCSSTagChecker.java:778)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.reloadRule(MapCSSTagChecker.java:858)
	at org.openstreetmap.josm.io.FileWatcher.processEvents(FileWatcher.java:160)
	at java.base/java.lang.Thread.run(Thread.java:834)

In fact, #11593 occurring again…

[simon04]

In 16907/josm:

see #19685, see #11593 - Add JavaCC ParseException.template

Source: ​https://github.com/javacc/javacc/blob/7.0.3/src/main/resources/templates/ParseException.template

[simon04]

In 16908/josm:

fix #19685, see #11593 - Fix NPE in JavaCC ParseException

[simon04]

In 16909/josm:

see #19685, see #11593 - Add non-regression test

[simon04]

Ticket #19667 has been marked as a duplicate of this ticket.