The code https://ideone.com/ctx92s works for 1 000 000. But on my PC it works only for 1024. Wen i am trting give him 1 000 000 - the Python crashes without any words: https://i.stack.imgur.com/1do06.png and in windows we can found this crash report: https://i.stack.imgur.com/nruoa.png --- so it works for low values and crashes on higher values. Buy its no bug... Than - What is it?

sorry - wrong ideone example this one better to look: https://ideone.com/aV9Z8p

CPython pushes a frame on the thread's stack for every Python frame. By default in Windows Python the thread's stack is allowed to grow up to about 2 MB. On Linux the default limit is 8 MB, but a higher limit can be set via `ulimit -s`. After the stack is full, pushing another value will crash the process due to a stack overflow. Windows raises a STATUS_STACK_OVERFLOW (0xC00000FD) exception. Linux raises a SIGSEGV signal (segmentation fault). The default interpreter recursion limit of 1,000 is set to raise a Python RecursionError well before you'd see a hard crash from a stack overflow. If we ballpark a C stack frame at about 1 KB in 64-bit Python, then the default stack size on Windows should support a recursion limit of about 2,000. For a recursion limit of 100,000, I would estimate a 100 MB stack size. You can call threading.stack_size(size_in_bytes) to reserve a larger stack size for new threads. However, in Python code it's better to rewrite such deeply recursive cases to use loops instead.

Thanks a lot! Grace and Honor!