Class destructor. Implementation error?

[ajvperth]

Hello,
possibly I found an implementation error in micropython?
on CPython this code:

Code: Select all

class Controller:

    def __init__(self):
        print('__init__()')
    
    def __del__(self):
        print('__del__()')
        
    def run(self):
        print('run()')

try:
    Controller().run()
except KeyboardInterrupt:
    print('\nTerminated, Ctrl-C pressed')
except BaseException as exc:
    print('\nUnhandled exception : ', type(exc), exc)

prints: __init__() then run() and __del__()
on micropython: __init__() and run().

_del__() is missing?? --> the destructor is not called?

[jimmo]

_del__() is missing?? --> the destructor is not called?

This is a documented Micropython limitation:

https://docs.micropython.org/en/latest/ ... ed-classes

The additional overhead of tracking finalisation state for classes would be non-trivial. (We do this in a limited form for built-in types though)

[pythoncoder]

I've believe this is a limitation of CPython too - IIRC the destructor is not guaranteed to be called until you quit the interpreter. In a firmware "run forever" type application that equates to no guarantee at all.

[ajvperth]

Thanks, for pointing me to the page with core language limitations.
I did read it but did not realize the consequences.