3.0.{0,1}: SystemError: <built-in function _escape_inner> returned NULL without setting an exception

[ervandew]

We are using markupsafe within a jinja2 environment, and ran into an issue not present in 2.1.5, but occurs in 3.0.0 and 3.0.1, running on python 3.12.6 and python 3.12.7:

Traceback (most recent call last):
  File "markupsafe_error.py", line 9, in <module>
    result = env.from_string('{{ value }}').render({'value': Something()})
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "lib/python3.12/site-packages/jinja2/environment.py", line 1304, in render
    self.environment.handle_exception()
  File "lib/python3.12/site-packages/jinja2/environment.py", line 939, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "<template>", line 1, in top-level template code
  File "lib/python3.12/site-packages/markupsafe/__init__.py", line 45, in escape
    return Markup(_escape_inner(str(s)))
                  ^^^^^^^^^^^^^^^^^^^^^
SystemError: <built-in function _escape_inner> returned NULL without setting an exception

It occurs when attempting to evaluate the result of escape in a jinja template coming from the __str__ of an object, when the jinja environment has autoescape set to True. I realize this is redundant (having autoescape + using escape), but this is in an older code base where tracking down all redundant uses is not ideal and does look to be a regression from 2.1.5 which does not produce an error.

from jinja2 import Environment
from markupsafe import escape

class Something:
  def __str__(self):
    return escape('something')

env = Environment(autoescape=True)
env.from_string('{{ value }}').render({'value': Something()})

Environment:

• Python version: 3.12.6 and 3.12.7
• MarkupSafe version: 3.0.0 and 3.0.1

I'm guessing one of the recent refactorings to the c code may have introduced this regression:
#434
#437

[davidism]

Duplicate of #472