Markup.__init__ causes error

[kernc]

I obviously don't expect you to debug my --pre CI runs, but what I read points to recent Jinja 3.0.0rc1 / markupsafe 2.0.0rc2 prereleases. Please see: https://github.com/kernc/backtesting.py/runs/2371946706?check_suite_focus=true#step:11:234

The error:

TypeError: object.__init__() takes exactly one argument (the instance to initialize)

issued here:

jinja/src/jinja2/utils.py

Line 843 in d77a91b

super().__init__(*args, **kwargs)

seems to indicate markupsafe.Markup for some reason is object rather than str. 😕

Environment:

• Python version: 3.8
• MarkupSafe version: 2.0.0rc2

[davidism]

It looks like Bokeh is doing from jinja2 import Markup. They should update to from markupsafe import Markup. (This has been the case for a while, but we only recently noticed and made it issue a deprecation warning.)

It does look like overriding __init__ to show a warning is causing issues in this case because of how subclassing str works, so I'll fix that, but ultimately Bokeh will need to update. You can report it to them if you'd like, or if they run their tests with DeprecationWarning turned into errors they'll see failures once they test against Jinja 3.0.

[kernc]

Reported to Bokeh in bokeh/bokeh#11174 and bokeh/bokeh#11175.

Many thanks for your feedback!

[davidism]

I'm not going to make an rc2 release quite yet, I'll wait to see what other feedback comes in. I'd suggest pinning your dependencies for testing (and possibly in general depending on whether you're a library or end-user project), unless you were deliberately testing all pre-releases.

[davidism]

pip install --pre -U jinja2 to get Jinja 3.0.0rc2.