#27403 Synthetic `UpdateChainLink` chain of `KBDataProducerTask` leads nowhere

enhancement

major

#26283

In-app configured global dialogs

#27411

Smart Startup/Shutdown

#27431

Deploy App Archetype to MavenCentral

minor

#27248

Predefine icons/cliques for buttons/dialogs with theme variables if possible

#27264

Selection components should not unpack one-element sets

#27267

ListModelBuilder shall return a collection in getModel(...).

#27365

Select default selection based on the last (current) selection

#27412

Bulk Dependency Update 2023/06

defect

major

#27388

No display of error text in composition tables

#27407

Selection of the grid disappears with F5

#27408

AbstractFlexDataManager logs warning when loading the same object multiple times

#27446

Incorrect license display for TopLogic modules in the license overview

minor

#27230

Command release service: exception rule does not work

#27275

I18N string as name attribute returns error

#27306

Option providers still do not update calculated suggested values

#27312

Application tests: No recording of inputs in I18N string attributes in grid possible

#27326

Memory hole: Personal configuration is not cleared properly

#27340

Administration: Maintenance mode does not work properly

#27341

TL script: NPE when regular expressions evaluate to "null".

#27343

LayoutEditor: Component channel selection for dialog open buttons wrong

#27344

Unwanted inlining of properties when creating a new app

#27349

Disappearing design buttons in tiles

#27364

Scheduler: Task execution fails with longer results

#27381

Incorrect preassignment in the chart JS template

#27385

Incorrect calculation of the sort order in references

#27400

ResKey: Missing quoting of non-primitive arguments

#27403

Synthetic `UpdateChainLink` chain of `KBDataProducerTask` leads nowhere

#27427

Potential NullPointerException when sorting the results of a quick search

#27429

Assertion error when setting incompatible value in ComplexField

defect

minor

#27403

Synthetic `UpdateChainLink` chain of `KBDataProducerTask` leads nowhere

PersistencyLayer

The tl:KBDataProducerTask creates an artificial UpdateChainLink chain to set its session to the revision being processed. The tl:UpdateChainLink of the latest KnowledgeBase revision has no successor.

If further changes are committed to the tl:KnowledgeBase during processing, an attempt may be made to navigate to the next UpdateChainLink. This results in a NullPointerException:

Stack trace

java.lang.NullPointerException
    at com.top_logic.knowledge.service.db2.DBKnowledgeBase.registerForCleanup(DBKnowledgeBase.java:5303)
    at com.top_logic.knowledge.service.db2.DBKnowledgeItem.updateWithOlderValues(DBKnowledgeItem.java:774)
    at com.top_logic.knowledge.service.db2.DBKnowledgeItem.updateValues(DBKnowledgeItem.java:730)
	at com.top_logic.knowledge.service.db2.DBKnowledgeItem.updateDataForRevision(DBKnowledgeItem.java:370)
    at com.top_logic.knowledge.service.db2.DBKnowledgeItem.findValues(DBKnowledgeItem.java:329)
	at com.top_logic.knowledge.service.db2.DBKnowledgeItem.valuesAlive(DBKnowledgeItem.java:585)
    at com.top_logic.knowledge.service.db2.DBKnowledgeBase.syncCacheLookupCache(DBKnowledgeBase.java:1415)
    at com.top_logic.knowledge.service.db2.DBKnowledgeBase.cleanupAndLookupCache(DBKnowledgeBase.java:5107)
	at com.top_logic.knowledge.service.db2.DBKnowledgeBase.getCachedKey(DBKnowledgeBase.java:5095)
    at com.top_logic.knowledge.service.db2.AbstractDBKnowledgeItem.getKnownKey(AbstractDBKnowledgeItem.java:125)
    at com.top_logic.knowledge.KnowledgeReferenceStorageImpl.loadObjectKey(KnowledgeReferenceStorageImpl.java:328)
	at com.top_logic.knowledge.ByIDReferenceStorageImpl.fetchValue(ByIDReferenceStorageImpl.java:88)
    at com.top_logic.dob.attr.storage.AbstractMOAttributeStorageImpl.loadValue(AbstractMOAttributeStorageImpl.java:73)
	at com.top_logic.knowledge.service.db2.AbstractDBKnowledgeItem.loadAttributeValues(AbstractDBKnowledgeItem.java:277)
	at com.top_logic.knowledge.service.db2.DBKnowledgeItem.refetch(DBKnowledgeItem.java:687)
    at com.top_logic.knowledge.service.db2.DBKnowledgeBase.findOrCreateItem(DBKnowledgeBase.java:5238)
	at com.top_logic.knowledge.service.db2.DBKnowledgeBase.findOrCreateItem(DBKnowledgeBase.java:5194)
    at com.top_logic.knowledge.service.db2.MonomorphicSearch$FullObjectResult.findNext(MonomorphicSearch.java:322)
    at com.top_logic.knowledge.service.db2.MonomorphicSearch$FullObjectResult.getAll(MonomorphicSearch.java:301)
	at com.top_logic.knowledge.service.db2.MonomorphicSearch.search(MonomorphicSearch.java:73)
    at com.top_logic.knowledge.search.AbstractCompiledQuery.search(AbstractCompiledQuery.java:70)
	at com.top_logic.knowledge.service.db2.AbstractAssociationQuery.search(AbstractAssociationQuery.java:147)
    at com.top_logic.knowledge.service.db2.AssociationCache.query(AssociationCache.java:318)
	at com.top_logic.knowledge.service.db2.AssociationCache.getOrCreateGlobalCache(AssociationCache.java:124)
    at com.top_logic.knowledge.service.db2.AssociationCache.lookup(AssociationCache.java:67)
	at com.top_logic.knowledge.service.db2.AssociationCache.getLinksDirect(AssociationCache.java:53)
    at com.top_logic.knowledge.service.db2.DBKnowledgeBase.resolveLinks(DBKnowledgeBase.java:4257)
	at com.top_logic.knowledge.service.AssociationQueryUtil.resolveWrappers(AssociationQueryUtil.java:54)
    at com.top_logic.knowledge.wrap.AbstractWrapper.resolveWrappersTyped(AbstractWrapper.java:997)
	at com.top_logic.knowledge.wrap.AbstractWrapper.resolveWrappersTyped(AbstractWrapper.java:968)
    at com.top_logic.contact.business.PersonContact.getPerson(PersonContact.java:147)
[See appendix for the remaining stack frames]

Test

Cannot be reliably reproduced.