Unable to get or set content in a QgsLayoutItemManualTable

[ThomasG77]

What is the bug or the crash?

I'm unable to get or set table content in a QgsLayoutItemManualTable and it crashes when trying to inspect existing manual table created using GUI.

You can find attached a minimum project (one layout with an existing item, no layers) to test my code

debug-fixed-content-layout.qgz.zip

Steps to reproduce the issue

Open the attached project

Open the PyQGIS console and execute first part

layout_name = 'demo1'
project = QgsProject.instance()
manager = project.layoutManager()
layout = manager.layoutByName(layout_name)
my_item = layout.itemById('debug')
my_frame = my_item.multiFrame()
# Working
print(my_frame.contents())

headers = ['header1', 'header2', 'headerother']
content = [[1, 2, 3], [4, 5, "debug3"]]
result = [[QgsTableCell(f'{c}') for c in line] for line in content]

my_frame.setHeaders([QgsLayoutTableColumn(h) for h in headers])

Then, line by line, execute the following to reproduce the issue

# Below line failed and complains about not accepting a list
my_frame.setTableContents(result)
# Was wondering why, so done. Expecting an object
# but the object is supposed to be a QgsLayoutTableContents of
# QgsLayoutTableRow of QgsTableCell and neither QgsLayoutTableContents
# and QgsLayoutTableRow are available in Python bindings
print(help(my_frame.setTableContents))

# Below line crash QGIS
my_frame.tableContents()

Versions

QGIS version
3.16.3-Hannover
QGIS code revision
94ac9f2
Compiled against Qt
5.9.5
Running against Qt
5.9.5
Compiled against GDAL/OGR
2.2.3
Running against GDAL/OGR
2.2.3
Compiled against GEOS
3.6.2-CAPI-1.10.2
Running against GEOS
3.7.1-CAPI-1.11.1 27a5e771
Compiled against SQLite
3.22.0
Running against SQLite
3.22.0
PostgreSQL Client Version
10.15 (Ubuntu 10.15-0ubuntu0.18.04.1)
SpatiaLite Version
4.3.0a
QWT Version
6.1.3
QScintilla2 Version
2.10.2
PROJ.4 Version
493
OS Version
Ubuntu 18.04.5 LTS
Active python plugins
processing_r;
exportDBmapper;
autoSaver;
LayerBoard;
qtiles;
ImageServerConnector;
qgis_resource_sharing;
processing_wbt;
profiletool;
QuickOSM;
splitmultipart;
quick_map_services;
geometry_paster;
qgisnetworklogger;
french_address;
qgis-maptiler-plugin;
DEMto3D;
SgmExpressionFunctions;
cartolinegen;
geo_sim_processing;
pluginbuilder3;
PluginLoadTimes;
DotMap;
firstaid;
cartography_tools;
qfieldsync;
mask;
qgis2web;
InvisibleLayersAndGroups;
Generalizer3;
lizmap;
french_locator_filter;
plugin_reloader;
LoadQSS;
db_manager;
processing

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

[ThomasG77]

@nyalldawson Thanks for the fix