0.15.0 creates an issue during initialization (python 3.8, aws beanstalk graviton) about flask-marshmallow

[Sillocan]

Seeing the same issue on our end.

[sirosen]

Hi there, thanks for reporting this!
I want to note up front that 0.15.0 is the first release in a couple of years, so there's a lot of potential drift to account for, as other packages have updated over time. I'll be trying to understand and fix issues as quickly as I can, but it may take some time.

Could you also let me know the version numbers of the relevant packages you're using?
In particular, versions of marshmallow, flask-sqlalchemy (if applicable), marshmallow-sqlalchemy, and sqlalchemy strike me as relevant. It's best to work out how to reproduce the issue before I try making any adjustments to fix it.

[ChriZzn]

Hi @sirosen,

i have the same Problem, i think it is related with this Update: https://github.com/sqlalchemy/sqlalchemy/releases/tag/rel_2_0_9

Because this change got also Backported to v1.4.48.

[Sillocan]

marshmallow-3.19.0
flask_marshmallow-0.15.0
Flask_SQLAlchemy-2.5.1
marshmallow_sqlalchemy-0.29.0
SQLAlchemy-1.4.47

[inbarshani]

[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"

[packages]
atomicwrites = "*"
boto3="*"
autopep8 = "*"
colorama = "*"
croniter = "*"
firebase-admin = "*"
flask = "==2.0.*"
flask-cors = "*"
flask-mail = "*"
flask-marshmallow = "==0.14.0"
flask-migrate = "*"
flask-sqlalchemy = "==2.5.1"
hubspot3 = "*"
intuit-oauth = "*"
marshmallow-sqlalchemy = "*"
mock = "*"
pdfkit = "*"
psycopg2-binary = "==2.9.5"
pylint = "*"
pytest = "==6.2.0"
python-dotenv = "~=0.21.1"
pytz = "*"
requests = "*"
shapely = "==1.7.1"
soracom = "==0.0.1.post0"
sqlalchemy = "==1.4.46"
coverage-threshold = "==0.4.4"
coverage = "==6.3.2"
orjson = "~=3.7.7"
deepdiff = "~=5.8.1"
flask-jwt-extended = "~=4.4.4"
werkzeug = "~=2.0.1"
flask-bcrypt = "*"
pytest-cov = "~=4.0.0"
pytest-xdist = "~=3.2.1"
filelock = "==3.9.0"
sqlalchemycollector = "*"

[dev-packages]
flake8 = "*"

[requires]
python_version = "3.8"

[sirosen]

It seems very likely that most of these issues stem from the fact that support for flask-sqlalchemy<3 was dropped. This was not correctly documented in the changelog before (sorry!), which has been fixed in the repo and will update on readthedocs with the next release.

There are two comments here which indicate flask-sqlalchemy v2, which supports this guess.

I have pretty limited availability the next few days to respond or work on things, so I'm just going to brain dump some thoughts (hopefully informative and uncontroversial):

• this is not a critical issue, since users can easily pin to v0.14.0 until they're ready to upgrade
• there's no plan to support flask-sqlalchemy v2 in a future release. I would only consider it in extraordinary circumstances -- my intent is to get this library on healthy footing again, including reasonable lower bounds for dependencies
• upgrading to flask-sqlalchemy v3 is a pretty minor matter for most apps -- I recently handled this at work and it was a chore but not a hard one -- and is my recommendation to most users
• as a general recommendation, you should be pinning dependencies for any deployed production applications (pdm, poetry, pipenv, pip-tools, etc)

That last point is not meant to put blame on anyone seeing problems -- if someone is having a bad time because this broke their app I'm genuinely sorry -- but to help make sure that folks walk away with the right conclusions. If you're not pinning dependencies, you're going to experience breakage sooner or later.

[sirosen]

I've been able to reproduce the initial report using flask-sqlalchemy 2.5.1, and confirm that it's fixed with flask-sqlalchemy 3.0.3.
As such, I'm going to close this as a (fixed) documentation issue about ending support for flask-sqlalchemy 2.x

Here's my reproducer for reference:

import flask

from flask_marshmallow import Marshmallow
from flask_sqlalchemy import SQLAlchemy


db = SQLAlchemy()
ma = Marshmallow()


def create_app() -> flask.Flask:
    app = flask.Flask("extapp")
    app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///:memory:"
    db.init_app(app)
    ma.init_app(app)
    return app


app = create_app()