more robust migrations

migrations/versions/c21f243b3640_add_profile_picture_to_user.py

@@ -19,11 +19,14 @@ depends_on = None
 
 def upgrade():
     # ### commands auto generated by Alembic - please adjust! ###
-    op.drop_table('contact')
     conn = op.get_bind()
     inspector = inspect(conn)
+    tables = inspector.get_table_names()
     columns = [col['name'] for col in inspector.get_columns('user')]
     
+    if 'contact' in tables:
+        op.drop_table('contact')
+    
     with op.batch_alter_table('user', schema=None) as batch_op:
         if 'profile_picture' not in columns:
             batch_op.add_column(sa.Column('profile_picture', sa.String(length=255), nullable=True))
@@ -33,8 +36,13 @@ def upgrade():
 
 def downgrade():
     # ### commands auto generated by Alembic - please adjust! ###
+    conn = op.get_bind()
+    inspector = inspect(conn)
+    columns = [col['name'] for col in inspector.get_columns('user')]
+    
     with op.batch_alter_table('user', schema=None) as batch_op:
-        batch_op.drop_column('profile_picture')
+        if 'profile_picture' in columns:
+            batch_op.drop_column('profile_picture')
 
     op.create_table('contact',
     sa.Column('id', sa.INTEGER(), autoincrement=True, nullable=False),