The offline cache doesn't work properly on the program that contains indirect recursive calls to real functions

[PGZXB]

t1.py

import taichi as ti

ti.init(arch=ti.cpu, offline_cache=True, offline_cache_file_path='one/path/to/cache')

@ti.experimental.real_func
def B(i: ti.i32):
  print(f'-> B ', end='')
  if i != 0:
    A(i - 1)

@ti.experimental.real_func
def A(i: ti.i32):
  print(f'-> A ', end='')
  if i != 0:
    B(i - 1)

@ti.kernel
def K1(i: ti.i32):
  print('K1 ', end='')
  A(i)
  print()
  
@ti.kernel
def K2(i: ti.i32):
  print('K2 ', end='')
  B(i)
  print()

K1(5)
K2(5)

t2.py

import taichi as ti

ti.init(arch=ti.cpu, offline_cache=True, offline_cache_file_path='one/path/to/cache')

@ti.experimental.real_func
def B(i: ti.i32):
  print(f'-> B ', end='')
  if i != 0:
    A(i - 1)

@ti.experimental.real_func
def A(i: ti.i32):
  # print(f'-> A ', end='')
  print(f'-> A^ ', end='')
  if i != 0:
    B(i - 1)

@ti.kernel
def K1(i: ti.i32):
  print('K1 ', end='')
  A(i)
  print()
  
@ti.kernel
def K2(i: ti.i32):
  print('K2 ', end='')
  B(i)
  print()

K1(5)
K2(5)

run python t1.py

• Output:

K1 -> A -> B -> A -> B -> A -> B
K2 -> B -> A -> B -> A -> B -> A

Then, run python t2.py

• Output:

# The output is wrong
K1 -> A^ -> B -> A^ -> B -> A^ -> B
K2 -> B -> A -> B -> A -> B -> A

• Correct output:

K1 -> A^ -> B -> A^ -> B -> A^ -> B
K2 -> B -> A^ -> B -> A^ -> B -> A^