#29580 RowSourceObserver: a disposed observer is still notified and throws NPE (_scope null) from DerivedViewChannel and GlobalModelEventForwarder

enhancement

major

#29659

TL Views: Popover-Element mit beliebigem Inhalt an einer auslösenden Schaltfläche

#29713

TL Views: a user cannot hide a tile of a <dashboard> and add it again later

#29755

React-UI: Auswahl in Objektlisten (<object-list selection>) – Karten direkt anwählbar

#29756

React view table: Excel export (parity with classic TableComponent) and generic download view action

#29757

React view table: show row count (total / filtered / selected) like the classic table

#29776

TL Views: Einheitliches Drag & Drop für Tabellen, Baum-Tabellen, Bäume und Kanban-Boards mit mehreren Drop-Operationen, Drop-Positionen und Drag-Arten

#29782

Concept: Discover right for the model based security (filtered object sources, masked form fields)

#29785

OpenAPI server: request bodies are not validated against the declared schema

#29786

MUI: Avatar (TLAvatar) mit Material UI darstellen

#29787

React UI: Atomare Bausteine (Schaltflächen, Menü-Auslöser, Checkboxen, Eingabefelder, Chips, …) sehen überall gleich aus und lassen sich durch eine Komponentenbibliothek (z.B. Material UI) ersetzen

#29797

XML import into existing data: resolve IDs against existing objects, skip known subtrees, optional references, language and variables from the input

#29799

Form dependencies: derived fields do not follow edited values; Java script functions cannot report what they read to the ScriptTracer

#29811

TL Views: a <button> ignores the display mode of its command and always shows icon and label

#29812

TL Views: a table column declares its own comparator; enumeration columns follow the enumeration's order

#29814

TL Views: no supported way for a server-side background source (a bus listener) to push a channel value into a view; only <start-job> does it through internal API

#29815

TL Views table: no per-row CSS class (a row cannot be marked as changed, stale or own)

#29816

TL Views table: a <computed-column> cannot be hidden by default (shown only through the column chooser)

#29821

Design System wave 3b: table, tree, column selection and text read the design system package

#29825

Design System: column selection of the React table – grouping as one select, checkbox first, visible and hidden columns apart

#29829

TL Views: Beschreibbarer Kanal, der aus anderen Kanälen vorbelegt wird

#29830

Transaction monitor: Select a time range or a revision range instead of a single day.

#29836

Design System wave 4a: dialog, window, drawer, snackbar and notice bar read the design system package

#29840

Persistent object wrapper hierarchy: remove dead and duplicated code, move stateless behavior into interface defaults, replace class identity checks

#29849

Configuration: an encrypted property value that is not a valid encrypted value is silently "decrypted" to garbage instead of being rejected

#29854

PowerPoint-Präsentationen aus TL-Script erzeugen: deklarative Folienbausteine, Export in eine Firmenvorlage, Analyse von Vorlagen

#29858

Privileged TL-Script functions: authorize a configured script as a whole by a command group on a computed security object

#29859

React-Einfachauswahl: Die aktuell gewählte Option fehlt in der Optionsliste

#29866

Design System wave 4b: app shell, app bar, sidebar and bottom bar read the design system package

#29870

Design System wave 4c: layout containers read the design system package

#29907

Entwicklerkommandos und Skript-Rekorder außerhalb des Produktivmodus für alle Benutzer

minor

#28605

Possibility to download a recorded script

#28995

Column filter should consider comparator of the column when sorting the options

#29801

TL Views: the split of <adaptive-detail> is configurable (size, unit, min-size on <selector> and <detail>; drawer width as drawer-size)

#29805

TL Views: a <value-input> is declared like a model attribute (mandatory, annotations) - a mandatory enumeration input offers no "no value" option

defect

critical

#29784

OpenAPI server: basic authentication of a technical user accepts an empty password when the configured password is empty (e.g. unset environment variable)

#29823

HistoryCompaction: Löschen von REVISION/REVISION_XREF und Umschreiben der Revisionsbereiche in je einer Transaktion lässt die Datenbank explodieren

major

#29580

RowSourceObserver: a disposed observer is still notified and throws NPE (_scope null) from DerivedViewChannel and GlobalModelEventForwarder

#29783

TLScriptFunctions: a script function is bound to an arbitrary overload of the same name, including a private one

#29788

Configuration: the error for an undecodable encrypted property echoes the value (e.g. a plain-text password) into the log

#29789

tl:generate-java fails on the first build after a TopLogic version change: it neither resolves the engine web fragments nor reads the project's own model sources

#29791

TL Views table: the row activation button runs the activation command without selecting its row, so commands reading the selection channel see another row (wrong breadcrumb label)

#29792

TL Views: a closed dialog (and a left tile-stack frame) stays visible for 1 s unless the application ships its own exit animation - move the demo's animations into the engine

#29800

Model patch of an existing database fails when a class gains a generalization and overrides its attributes in the same change

#29806

WrapperGenerator: every top-level class of a module with a singleton extends StructuredElement (regression of #26716)

#29807

WrapperGenerator: classifier constants of two enumerations collide, the generated factory does not compile

#29808

TL Views: the <on-submit> command of a text or number <value-input> runs on Enter only, not when the field is left with a changed value

#29810

TL Views: the selection channel of a <tree> keeps an object deleted in another view, and scripts over it fail

#29813

TL Views: a <tree> does not react to a change of an object it does not display yet, so a node that becomes a child of a shown node does not appear

#29822

CompactHistoryTask: Wartungsfenster bleibt nach dem Lauf aktiv, Task-Ende geht im Neustart der Persistenzschicht verloren

#29824

TL Views table: "Standard wiederherstellen" in the column selection drops a declared group-by (and does not restore the declared sort)

#29837

TestCompileJSPs modifies the module's source webapp and breaks concurrently running scripted tests of the same module

#29838

ClusterManager: a database connection that failed in a cluster transaction is returned to the pool and keeps failing every refetch

#29846

Changing the type of a column with content fails on Oracle (ORA-01439) and of an indexed column on MS SQL Server

#29848

ReportQueueTest.testAddJob fails sporadically: the queue thread may process the job before the test checks that it is queued

#29871

TestZipper.testEmptyFolder fails depending on the order in which the file system lists a folder

#29878

React UI does not react behind a proxy that buffers or refuses the window event stream

minor

#29766

TL-Script add() wirft UnsupportedOperationException bei Multi-Referenz auf transientem Objekt

#29804

XML import: line and column of a message location are formatted with a thousands separator ("line 4,433")

#29809

TL Views: a <value-input type="tl.core:Binary"> shows the file name as text instead of the binary field (no upload, no download)

task

minor

#29790

Upgrade guide 7.11 to 8.0: add the Maven >= 3.8.9 requirement, state that 7.10.x applications can follow it, and point to it from the release notes

#29793

Developer docs: recipe for an application-defined primitive type whose display depends on the owning object (custom datatype, value class, type-level storage, label provider, input control)

defect (User-visible)

major

#29580

RowSourceObserver: a disposed observer is still notified and throws NPE (_scope null) from DerivedViewChannel and GlobalModelEventForwarder

ReactUI

Found in BOS/Consulting (React view layer, TopLogic 8.0.0-alpha8) while building a routing sidebar (ScopeRailControl, a RoutingParticipant that rebuilds its rail when the route's first segment changes).

Symptom 1 (HTTP 500): when the control replaced its rail inside onAttach (route resolution in RouteManager.tryResolvePending → ReactControl.onAttach → ViewServlet.renderPage), the outgoing rail's RowSourceObserver was disposed inside a channel notification, but DerivedViewChannel.recompute still notified the snapshot of listeners it had taken, so the disposed observer ran registerObjectListeners with _scope == null:

java.lang.NullPointerException: Cannot invoke "ModelScope.addModelListener(...)" because "this._scope" is null
  at RowSourceObserver.registerObjectListeners(RowSourceObserver.java:167)
  at DerivedViewChannel.recompute(DerivedViewChannel.java:147)
  at ScopeRailControl.activateRoute(...)
  at RouteManager.tryResolvePending(RouteManager.java:192)
  at ReactControl.onAttach(ReactControl.java:1070)
  at ViewServlet.renderPage(ViewServlet.java:492)

The application worked around it by deferring the disposal through ChannelNotificationScope.afterNotification (Consulting PR #192).

Symptom 2 (swallowed ERROR): the same disposed observer is reached by a second delivery path, a model event synthesised later in the same request:

ERROR EventBuilder - Failed to deliver change event to listener: RowSourceObserver@3a71961c
java.lang.NullPointerException: Cannot invoke "ModelScope.removeModelListener(...)" because "this._scope" is null
  at RowSourceObserver.deregisterObjectListeners(RowSourceObserver.java:176)
  at RowSourceObserver.reEvaluate(RowSourceObserver.java:148)
  at RowSourceObserver.notifyChange(RowSourceObserver.java:139)
  at EventBuilder.notifyListeners(EventBuilder.java:474)
  at GlobalModelEventForwarder.synthesizeModelEvents(GlobalModelEventForwarder.java:165)
  at ReactServlet.handleCommand(ReactServlet.java:487)

EventBuilder catches and logs it; observed once, on the creation of the first project of a fresh installation.

Expected: a RowSourceObserver that has been disposed (its _scope cleared) must not act on a notification: either the observer checks its own liveness at the top of notifyChange/`reEvaluate`/`registerObjectListeners` and returns, or the channel/event dispatch drops listeners that were removed during the notification instead of notifying a CopyOnWriteArrayList snapshot. Any control that tears down a subtree inside a channel notification hits this today.

Reference: BOS/Consulting PRs #187 and #192 (Gitea), review reports of 2026-09-14.

Lösung

Ursache ist allgemein: Eine Benachrichtigung läuft über eine vorab gezogene Liste der Listener (CopyOnWriteArrayList-Snapshot bei Kanälen, gesammelte Empfängermenge im EventBuilder). Ob ein Listener darin noch angemeldet ist, lässt sich mit der add/`remove(listener)`-API nur durch Suche beantworten. Daher ist die Anmeldung auf Handles umgestellt:

Eine Anmeldung liefert ein Registration-Handle (com.top_logic.basic.listener). dispose() markiert es als inaktiv und gibt die Referenz auf den Listener frei; eine laufende Benachrichtigung überspringt inaktive Anmeldungen in O(1). Ein während einer Benachrichtigung abgemeldeter Listener wird damit nicht mehr aufgerufen – für jeden Listener, nicht nur RowSourceObserver.
Speicher ist AbstractObservable/`AbstractListeners` (com.top_logic.basic): Die Liste wird nur ergänzt, nie in-place verkleinert; eine Benachrichtigung läuft bis zur Länge bei ihrem Start, so dass während einer Benachrichtigung nichts kopiert werden muss. Abgemeldete Einträge werden amortisiert entfernt (sobald es mehr tote als lebende gibt, in eine neue Liste), so dass dispose() amortisiert O(1) kostet.
ViewChannel.addListener und ModelScope.addModelListener liefern das Handle; DefaultViewChannel, DerivedViewChannel und DefaultModelScope bauen darauf auf (DefaultModelScope entfernt den Eintrag eines Objekts/Typs, sobald dessen letzte Anmeldung abgemeldet ist). Der EventBuilder sammelt Anmeldungen statt Listener, benachrichtigt jeden Listener höchstens einmal und überspringt inaktive.
removeListener/`removeModelListener` bleiben für Code außerhalb der Engine erhalten (meldet alle Anmeldungen des Listeners ab), sind aber zugunsten von Registration.dispose() als deprecated markiert. Die Aufrufer in der Engine (View-Layer-Controls, LayoutComponent, ObservedObjects, HTMLTemplateFormProvider, …) halten das Handle ihrer Anmeldung und geben es frei. LayoutComponent meldet dabei genau die Beobachtungen ab, die es angemeldet hat (statt sie beim Abmelden aus dem aktuellen Modell neu zu berechnen).
Kanäle sind nicht synchronisiert; sie werden unter der Interaktion der Session (Request bzw. Hintergrund-Job über ReactWindowReplay.inWindow) von jeweils einem Thread benutzt.

Hinweis für Entwickler: addListener/`addModelListener` haben einen anderen Rückgabetyp; Module, die dagegen kompiliert sind, müssen neu übersetzt werden (sonst NoSuchMethodError). removeListener/`removeModelListener` sind deprecated: das Handle des add-Aufrufs aufheben und dispose() aufrufen.