Alter timestamp column on Postgres fails due to missing column length

[circulon]

Migrated from: MasoniteFramework/orm#921
Original author: @dapicester
Originally opened: 2025-02-20
Original state: closed

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I am migrating from Orator. I have a table where I used to define __timestamps__ = ["created_at"] which seems to be unsupported by Masonite ORM. So I set __timestamps__ = False. The actual column on the database table has no default value, so I add a migration:

class AddDefaultToCreatedAt(Migration):
    def up(self):
        with self.schema.table("mytable") as table:
            table.timestamp("created_at").default("CURRENT_TIMESTAMP(6)").change()

The migration fails with the current error:

  QueryException

  syntax error at or near "None"
  LINE 1: ... "stats" ALTER COLUMN "created_at" TYPE TIMESTAMP(None), ALT...
                                                               ^


  at .venv/lib/python3.9/site-packages/masoniteorm/connections/PostgresConnection.py:222 in query
      218│                     if "SELECT" in cursor.statusmessage:
      219│                         return cursor.fetchall()
      220│                     return {}
      221│         except Exception as e:
    → 222│             raise QueryException(str(e)) from e
      223│         finally:
      224│             if self.get_transaction_level() <= 0:
      225│                 self.open = 0
      226│                 self.close_connection()
make: *** [migrate] Error 1

With a debugger I have been able to debug the Blueprint instance:

> blueprint._last_column.name
'mytable'
> blueprint._last_column.type
'timestamp'
> blueprint._last_column.length
None

I got the migration to complete by manually setting _last_column.length = 6 in the debugger session.
Unfortunately I have not been able to find out where the length is actually set, now why it's set to None.