Fix migrations

backend/alembic/versions/017_admin_logs_nullable_admin_id.py

@@ -9,6 +9,7 @@ from typing import Sequence, Union
 
 from alembic import op
 import sqlalchemy as sa
+from sqlalchemy import inspect
 
 
 # revision identifiers, used by Alembic.
@@ -18,15 +19,29 @@ branch_labels: Union[str, Sequence[str], None] = None
 depends_on: Union[str, Sequence[str], None] = None
 
 
+def is_column_nullable(table_name: str, column_name: str) -> bool:
+    """Check if a column is nullable."""
+    bind = op.get_bind()
+    inspector = inspect(bind)
+    columns = inspector.get_columns(table_name)
+    for col in columns:
+        if col['name'] == column_name:
+            return col.get('nullable', True)
+    return True
+
+
 def upgrade() -> None:
     # Make admin_id nullable for system actions (like auto-unban)
-    op.alter_column('admin_logs', 'admin_id',
-                    existing_type=sa.Integer(),
-                    nullable=True)
+    # Only alter if currently not nullable
+    if not is_column_nullable('admin_logs', 'admin_id'):
+        op.alter_column('admin_logs', 'admin_id',
+                        existing_type=sa.Integer(),
+                        nullable=True)
 
 
 def downgrade() -> None:
     # Revert to not nullable (will fail if there are NULL values)
-    op.alter_column('admin_logs', 'admin_id',
-                    existing_type=sa.Integer(),
-                    nullable=False)
+    if is_column_nullable('admin_logs', 'admin_id'):
+        op.alter_column('admin_logs', 'admin_id',
+                        existing_type=sa.Integer(),
+                        nullable=False)