Bug when exporting Postgis layers with several geometry columns

[Tonio0774]

What is the bug or the crash?

Since version 3.28, layers with multiple geometry columns are impossible to export.

Steps to reproduce the issue

1- create a post gis layer with 2 geometries (the_geom & the_geom_3857) 2- export in shape leaving the default parameters 3-error message: Vector file export failed. Error: Unsupported type for field the_geom_3857

Versions

3.28.7

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

[Tonio0774]

it also prevents the smooth running of simple functions such as merging and buffer creation

[agiudiceandrea]

@Tonio0774, which version of QGIS the issue doesn't occur with?

[Tonio0774]

@Tonio0774, which version of QGIS the issue doesn't occur with?

it worked in all previous versions 3.22 and 3.16. in version there was a change that when there is a second column surveyor when postgis then all functions and processing no longer work.

in previous versions the second surveyor column was recognized as text in the settings.

[weca-theo]

Can confirm exporting works fine on 3.22.8. Exported a table with 6 geometry columns to GPKG. Exported and loaded to map fine.

[agiudiceandrea]

Already reported at #52225