Project DXF export does not allow to use attribute as DXF layer name

[dr1542]

This error began from version 3.18.0
In project DXF export dialog the drop down list of attributes for exported layers is frozen

QGIS version	3.18.1-Zürich	QGIS code revision	202f1bf
Compiled against Qt	5.11.2	Running against Qt	5.11.2
Compiled against GDAL/OGR	3.1.4	Running against GDAL/OGR	3.1.4
Compiled against GEOS	3.8.1-CAPI-1.13.3	Running against GEOS	3.8.1-CAPI-1.13.3
Compiled against SQLite	3.29.0	Running against SQLite	3.29.0
PostgreSQL Client Version	11.5	SpatiaLite Version	4.3.0
QWT Version	6.1.3	QScintilla2 Version	2.10.8
Compiled against PROJ	6.3.2	Running against PROJ	Rel. 6.3.2, May 1st, 2020
OS Version	Windows 10 (10.0)
Active python plugins	db_manager; MetaSearch; processing

[gioman]

In project DXF export dialog the drop down list of attributes for exported layers is frozen

@dr1542 is this in "in project > import/export > export project to DXF" ?

[dr1542]

@gioman yes, it is in "Project->Import/Export->Export Project to DXF..."

[agiudiceandrea]

I can confirm the issue on Windows with QGIS 3.18.1, while the issue doesn't occur with QGIS 3.16.5.
@dr1542 are you sure the issue also occurs with QGIS 3.18.0?

[dr1542]

@agiudiceandrea

are you sure the issue also occurs with QGIS 3.18.0?

sorry. i can't check it now. When i trying open this dialog qgsi3.18.0 crashes.

[agiudiceandrea]

Indeed, with QGIS 3.18.0 opening the Project to DXF export dialog makes QGIS crash.

It seems the crash in QGIS 3.18.0 was a side effect of #39577 (see #41900 (comment))

The Project to DXF dialog crashing issue was then fixed in 3.18.1 with #41918 (#41925) by @elpaso but apparently he didn't noticed that the functionality was not completely restored.