db_persist has problem with postgres

[Twili Spar]

Environment:

Python version: 3.13.3
Django version: 6.0.7
psycopg version: 3.2.12
Postgres version: 18.1

---

Explain the bug:

Here is my code:

tmp = models.GeneratedField(
        db_persist=False,  # In here, I've set the column type as virtual
        expression=models.Q(standard_symbol_tmp__isnull=False),
        null=True,
        output_field=models.BooleanField(),
    )

And when I do makemigrations all things are good, but on migrating, django says:

SystemCheckError: System check identified some issues:

ERRORS:
symbol.Symbol.tmp: (fields.E221) PostgreSQL does not support non-persisted GeneratedFields.
        HINT: Set db_persist=True on the field.

While I know that Postgres supports the VIRTUAL and STORED generated columns, here is the postgres release note ref:
​https://www.postgresql.org/about/news/postgresql-18-released-3142/

While the migration file is created and is like:

class Migration(migrations.Migration):

    # ...rest of the code ...

    operations = [
        migrations.AddField(
            model_name="symbol",
            name="tmp",
            field=models.GeneratedField(
                db_persist=False,
                expression=models.Q(("standard_symbol_tmp__isnull", False)),
                null=True,
                output_field=models.BooleanField(),
            ),
        ),
    ]

And when I set db_persist to True AND DO NOT TOUCH THE migration file and migrate, all things are good, column creates as VIRTUAL in postgres, NOT STORED.

[Twili Spar]

A quick fix

I played with the migration files, when I changed the db_persist=True in my models.py file, I knew that if I run makemigrations one more time, django will create a new migration file for me which changes my VIRTUAL column to STORED, that I didn't wanted, so I did like:

1. Updated the models.py, db_persist=True
2. Run makemigrations one more time to have a migration file like:

   operations = [
           migrations.AlterField(
               model_name="symbol",
               name="tmp",
               field=models.GeneratedField(
                   db_persist=True,  # 👈 This would change the VIRTUAL to STORED in DB, which is not good
                   expression=models.Q(("standard_symbol_tmp__isnull", False)),
                   null=True,
                   output_field=models.BooleanField(),
               ),
           ),
       ]
   

3. I didn't want to run migrate with --fake, so I migration file to

   operations = [
           migrations.SeparateDatabaseAndState(
               state_operations=[
                   migrations.AlterField(
                       model_name="symbol",
                       name="tmp",
                       field=models.GeneratedField(
                           db_persist=True,
                           expression=models.Q(("standard_symbol_tmp__isnull", False)),
                           null=True,
                           output_field=models.BooleanField(),
                       ),
                   ),
               ],
               database_operations=[],  # 👈 nothing runs against the DB
           ),
       ]
   

Then when I run the migrate, Django's migration state updated and my DB DIDN'T CHANGED.