all Python 3inspectfunction

inspect.stack()

stack and frames

A list of FrameInfo records for every frame on the call stack, from the current function out to the module.

Syntax

inspect.stack(context=1) -> list[FrameInfo]

The call is expensive: for every frame inspect reads the source file to fill code_context, so hot code uses inspect.stack(0) or fetches one frame via inspect.currentframe().f_back. The second trap is a leak: a FrameInfo holds a live frame, the frame holds its local variables, and a list stored in a local variable closes a reference cycle, so objects outlive the function until the garbage collector runs. Delete the result in a finally block (del st). File paths and line numbers depend on where the file lives.

Examples

import inspect
def inner():
    st = inspect.stack(0)  # 0 — без чтения исходников
    try:
        return [fi.function for fi in st]
    finally:
        del st  # разорвать цикл кадр → список → кадр
def outer():
    return inner()
print(outer())  # → ['inner', 'outer', '<module>']
print(inspect.stack()[0].lineno)  # → ? номер строки в файле

import gc, inspect, weakref
class Obj: pass
def work():
    obj = Obj()
    st = inspect.stack(0)  # кадр ссылается на st, st — на кадр
    return weakref.ref(obj)
gc.disable()
r = work()
print(r() is None)  # → False — obj пережил функцию
gc.collect()
print(r() is None)  # → True — освободил только сборщик циклов

inspect.stack()

Syntax

Examples

See also