[Postgres] default value displayed instead of NULL

[troopa81]

What is the bug or the crash?

When a row contains NULL, the DEFAULT expression is displayed instead of NULL

Steps to reproduce the issue

1. Create a Postgres test table and add some rows

create table default_int_2 ( id serial primary key, entier integer DEFAULT 2+2 );
insert into default_int_2 ("entier") values(1);
insert into default_int_2 ("entier") values(NULL);
insert into default_int_2 ("entier") values(4);

2. Open the attribute table
3. the default value is displayed although it should be NULL
   

Versions

QGIS master bc37888854

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

Incoming PR!