Bug report

Bug description:

This includes any function that calls _PyEval_GetGlobals() or _PyEval_GetFrameLocals(). Here's a list of the ones I noticed:

• globals()
• locals()
• dir()
• vars()
• exec()
• eval()

For example:

from concurrent import interpreters
interp = interpreters.create()

# This raises SystemError.
interp.call(eval, 'True')

Ideally it would fall back to __main__.__dict__ for the globals and locals.

FWIW, this is most obvious with subinterpreters, but a similar problem applies to any user of the C-API that doesn't have a frame set.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-135443: Sometimes Fall Back to __main__.__dict__ For Globals #135491
• [3.14] gh-135443: Sometimes Fall Back to __main__.__dict__ For Globals (gh-135491) #135593