Cartographic label placement with "Distance Offset: From Symbol Bounds" shows offset for MultiPoint features

[mblesius]

What is the bug or the crash?

The cartographic labeling placement mode adds a large offset to labels of MultiPoint geometries when the Distance offset from option is set to From Symbol Bounds. For single-part geometries, the offset does not occur.

In the screenshot below, compare the expected behavior that occurs with the labeling of Point 2 with the undesired behavior that occurs for the features Point 1 and Point 3.

Steps to reproduce the issue

1. Add a MultiPoint vector layer with multi-part geometries to a new QGIS project
2. Turn on labeling
3. By default, cartographic labeling should already be selected
4. Make sure that the Distance offset from option is set to From Symbol Bounds

Test data set from the screenshot:
multipoint.zip

Versions

QGIS version	3.30.2-'s-Hertogenbosch	QGIS code revision	0992b53
Qt version	5.15.3
Python version	3.9.5
GDAL/OGR version	3.6.4
PROJ version	9.2.0
EPSG Registry database version	v10.082 (2023-02-06)
GEOS version	3.11.2-CAPI-1.17.2
SQLite version	3.41.1
PDAL version	2.5.2
PostgreSQL client version	unknown
SpatiaLite version	5.0.1
QWT version	6.1.6
QScintilla2 version	2.13.1
OS version	Windows 10 Version 2009
Active Python plugins
db_manager	0.1.20
grassprovider	2.12.99
MetaSearch	0.3.6
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

[elpaso]

I briefly looked at the code, the obstacle geometry is calculated on the bbox of the geometry collection on purpose, see QgsVectorLayerLabelProvider::getPointObstacleGeometry which sets the symbol size, which is then used for the offset in FeaturePart::createCandidatesAtOrderedPositionsOverPoint the single point symbol size is not available at that point so I'm not really sure what should be done here.

@nyalldawson this looks like a bug to me, what do you think?