Map Layout composer - Legend item expression not displaying correctly

[Hopper92]

What is the bug or the crash?

When trying to set a legend item with an expression to rename to another field value the legend displays the expression rather than the target field value.

Steps to reproduce the issue

Set legend to auto update and only show items inside linked map:

Expression for the target layer and confirmation it is valid in the preview:

The legend in the map composer showing the expression rather than the target "unitname" value:

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
DataPlotly
4.0.1
debug_vs
0.7
enmapboxplugin
3.12.1
FreehandRasterGeoreferencer
0.8.3
geoscience
1.11
inspireatomclient
0.8.1
MagneticDeclination
2.3.1
mapswipetool_plugin
1.2
Mergin
2023.1
processing_saga_nextgen
0.0.7
ProjectPackager
0.7.2
project_report
1.2
qfieldsync
v4.4.9
Qgis2threejs
2.7.1
QGISSortAndNumber-master
1.0
quick_map_services
0.19.33
SemiAutomaticClassificationPlugin
7.10.11
slyr
6.3.1
slyr_community
4.0.7
splitmultipart
1.0.0
SpreadsheetLayers
2.1.0
SRTM-Downloader
3.1.17
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

I hope this one is an easy fix or an easy workaround is possible? Thankyou!

[roya0045]

Not a bug, the problem is that the expression generator has a feature context where it shouldn't have one to reflect the legend.

[Hopper92]

Not a bug, the problem is that the expression generator has a feature context where it shouldn't have one to reflect the legend.

Thankyou for the response Alex. I don't really understand though, you might have to dumb it down for me haha. Is there a way to achieve what I want without having to manually type the other field value into the legend items?

[roya0045]

Depends on what you're using for the symbology. If it's only a single field you can use the collection function with the filter set to replicate the symbology rule used and pick the first element of the returned array. Though for that to work at the moment it will work in your symbol label is exactly the same value as what is used to perform the classification.