Default value with an expression and "apply on update"

[aliasatp]

What is the question?

Hi all,
I'm using lizmap 3.5, I have a QGIS project with some expressions as default value for fields. Editing with Lizmap I realised that "apply on update" doesn't work. Instead virtual fields are calculated but not visible.
Am I doing something wrong?
Thanks

Versions

QGIS 3.22.10
QGIS server LTR 3.22
LIZMAP 3.5.1

Check Lizmap plugin

• I have done the step just before in the Lizmap QGIS desktop plugin before opening this ticket. Otherwise, my ticket is not considered valid and might get closed.

QGIS server version, only if the section above doesn't mention the QGIS Server version

3.22.9

Operating system

WINDOWS SERVER R12

Browsers

Firefox

Browsers version

FIREFOX 104.0.2

Relevant log output

No response

[3liz-bot]

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[Gustry]

The expression for default value only works for new objects.
It's not yet supported for editing an existing object.

Let us know if you are really interested. As far as I can remember, it were some technical limitations.

[josemvm]

The expression for default value only works for new objects.

the expression for default value doesn't work for new objects on lwc 3.6(.4)

[Gustry]

the expression for default value doesn't work for new objects on lwc 3.6(.4)

it depends also on the expression used it self : does it need the current geom ? does it need a previous field from the form ?
Even me, I don't know which use cases. For sure, the easiest expression having a single value, like @lizmap_user or now() works for instance.

[gioman]

it depends also on the expression used it self : does it need geom ? does it need a previous field from the form ?

@Gustry for expression involving geometries (example from point fill X and Y values in the table) would not be enough to force users to first draw/edit the geometry and then allow them fill the attributes?

Having expression that fill a field based on the content of another field in the same form is simply impossible to obtain in LMWC or "just" hard to implement?