[furcas-discussion] [IMP] Incremental Lexer Crashes

[Stephan Erb]

Hey Thomas,

the IMP branch contains the first partially working IMP editor (see
[1]). Unfortunately the incremental lexer is crashing regularly and I am
unable to find the cause.

The lexer dies with: 

java.lang.ArrayIndexOutOfBoundsException
	at java.lang.System.arraycopy(Native Method)
	at org.eclipse.emf.common.util.BasicEList.addUnique(BasicEList.java:446)
	at org.eclipse.emf.common.notify.impl.NotifyingListImpl.doAddUnique(NotifyingListImpl.java:393)
	at org.eclipse.emf.common.notify.impl.NotifyingListImpl.addUnique(NotifyingListImpl.java:377)
	at org.eclipse.emf.common.util.AbstractEList.add(AbstractEList.java:345)
	at com.sap.ide.cts.parser.incremental.IncrementalLexer.addTokenIfNecessaryAndUpdateOffetsAndLengths(IncrementalLexer.java:675)
	at com.sap.ide.cts.parser.incremental.IncrementalLexer.lexPhase(IncrementalLexer.java:528)
	at com.sap.ide.cts.parser.incremental.IncrementalLexer.lex(IncrementalLexer.java:160)
	at com.sap.ide.cts.parser.incremental.antlr.ANTLRIncrementalLexerAdapter.lex(ANTLRIncrementalLexerAdapter.java:301)
	at com.sap.furcas.ide.editor.imp.services.FurcasParseController.parse(FurcasParseController.java:138)
	at com.sap.furcas.ide.editor.commands.ParseCommand.execute(ParseCommand.java:30)

At lines 518 and 519 within the IncrementalLexer we seem to have
inconsistently versioned TextBlocks: We have a token and its parent
block within the previous version. Now we map both to the current
version. However, during this process, the parent child relation seems
to get lost. The block does no longer contain the token. 

Given your experience with all this TextBlocks versioning, any idea
where I should start digging? 

Thanks!
Stephan

PS: If you want to try it yourself you have to install IMP from
http://download.eclipse.org/technology/imp/updates/


[1]
https://github.com/FURCAS-dev/FURCAS/blob/imp/DSLEngineering/com.sap.furcas.ide.editor/src/com/sap/furcas/ide/editor/imp/