Injecting variables into locals

[Technologicat]

In short: in recent Pythons, impossible, by design. This is probably a good thing.

In Python ≤ 3.6, as discussed on stupidpythonideas, there was PyFrame_LocalsToFast in the CPython C API, which could be accessed via ctypes. This no longer works in 3.7 and later (PEP 558).

The alternative of using inspect.stack() and mutating the f_locals attribute of the frame object doesn't work, either.

See also Everything in Python is mutable.

(This issue is intentionally left open to collect links to related reading.)