'_SQLAlchemyState' object has no attribute 'session'

[Nilster]

Hi there, I am noticing an issue with flask-marshmallow==0.15.0.

File "/src/manage.py", line 5, in
app = create_app()
File "/src/themis/app.py", line 69, in create_app
initialise_extensions(app)
File "/src/themis/app.py", line 79, in initialise_extensions
ma.init_app(app)
File "/usr/local/lib/python3.10/site-packages/flask_marshmallow/init.py", line 116, in init_app
self.SQLAlchemySchema.OPTIONS_CLASS.session = db.session
AttributeError: '_SQLAlchemyState' object has no attribute 'session'

It is working fine with flask-marshmallow==0.14.0 but since launch of 0.15.0, our build pipeline has started to fail because of this issue. Here is trimmed down list of modules for the trio of flask, marshmallow and sqlalchemy

Flask==2.2.2
Flask-SQLAlchemy==2.5.1
psycopg2-binary==2.9.3
itsdangerous==2.1.2
marshmallow==3.19.0
marshmallow-sqlalchemy==0.28.1
SQLAlchemy==1.4.46
flask-migrate==4.0.4

Let me know if you need any more info to recreate the issue.

Thanks.

[sirosen]

Hi there!

The latest version of flask-marshmallow does not support flask-sqlalchemy version 2.5.1; that's what causes this issue. You'll need to coordinate any update to the last flask-marshmallow with flask-sqlalchemy version 3, or pin back your version of flask-marshmallow to v0.14.0.

I'm also going to take a look at adding a feature to detect and emit a more appropriate error message in this case, as you're not the first to encounter this.

[Nilster]

Ok, thanks for the response.

[rbjones92]

Solved my question, thank you sironsen