Adding a new feature through attribute table on an empty layer crashes QGIS

[ViperMiniQ]

What is the bug or the crash?

Trying to add a new feature by opening attribute table crashes QGIS as soon as you press the Add feature button.

Steps to reproduce the issue

1.) Create a temporary vector layer with no fields.
2.) Open attribute table.
3.) Click on Add feature button and observe crash.

Versions

QGIS version	3.99.0-Master
QGIS code revision	825888e6fa3
Libraries
Qt version	6.10.1
Python version	3.14.2
GDAL version	3.11.5 — Eganville
PROJ version	9.6.2
EPSG Registry database version	v12.013 (2025-05-26)
GEOS version	3.14.1-CAPI-1.20.5
SFCGAL version	No support
GeographicLib version	No support
SQLite version	3.50.2
PDAL version	2.9.3
PostgreSQL client version	18.1
SpatiaLite version	5.1.0
QWT version	6.2.0
QScintilla2 version	2.14.1
OS version	Fedora Linux 43 (KDE Plasma Desktop Edition)
This copy of QGIS writes debugging output.
Active Python plugins
MetaSearch	0.3.6
db_manager	0.1.20
grassprovider	2.12.99
processing	2.12.99

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[agiudiceandrea]

Python Stack Trace
Windows fatal exception: access violation

Current thread 0x00002f00 (most recent call first):

Stack Trace

QSortFilterProxyModel::default constructor closure' : QConcatenateTablesProxyModel::headerData : QObject::qt_static_metacall : QMetaObject::activate : QAbstractItemModel::dataChanged : QSortFilterProxyModel::default constructor closure' :
QConcatenateTablesProxyModel::headerData :
QObject::qt_static_metacall :
QMetaObject::activate :
QAbstractItemModel::dataChanged :
QgsAttributeTableModel::reload :
QgsAttributeTableDialog::mActionAddFeatureViaAttributeTable_triggered :
QgsAttributeTableDialog::mActionAddFeature_triggered :
pdal::operatorQgsDecorationGrid::hasFixedMapPosition :
QgisApp::cadDockWidget :
QgsDecorationGrid::hasFixedMapPosition :
QgsMapLayerStyleCommand::id :
QObject::qt_static_metacall :
QMetaObject::activate :
QAction::activate :
QAbstractButton::click :
QAbstractButton::mouseReleaseEvent :
QToolButton::mouseReleaseEvent :
QWidget::event :
QApplicationPrivate::notify_helper :
QApplication::notify :
QgsApplication::notify :
QCoreApplication::notifyInternal2 :
QApplicationPrivate::sendMouseEvent :
QWidgetRepaintManager::updateStaticContentsSize :
QWidgetRepaintManager::updateStaticContentsSize :
QApplicationPrivate::notify_helper :
QApplication::notify :
QgsApplication::notify :
QCoreApplication::notifyInternal2 :
QGuiApplicationPrivate::processMouseEvent :
QWindowSystemInterface::sendWindowSystemEvents :
QEventDispatcherWin32::processEvents :
QWindowsGuiEventDispatcher::processEvents :
QEventLoop::exec :
QCoreApplication::exec :
main :
BaseThreadInitThunk :
RtlUserThreadStart :

QGIS Info
QGIS Version: 3.99.0-Master
QGIS code revision: 7d2ca37
Compiled against Qt: 6.8.1
Running against Qt: 6.8.1
Compiled against GDAL: 3.13.0dev-bc43b4b5a3
Running against GDAL: 3.13.0dev-fdcf0e02ec

System Info
CPU Type: x86_64
Kernel Type: winnt
Kernel Version: 10.0.18362

[agiudiceandrea]

The issue doesn't occur running QGIS LTR 3.40.15 and QGIS 3.44.7.