3.12 tracing regression: a conditional in a finally block will revisit the condition before exiting the block. #105658
Description
Python 3.12 introduced a change in tracing behavior. Now a conditional in a finally block will revisit the condition before exiting the block.
Here is test.py:
import sys print(sys.version) def example(raise_exc: bool, enter_finally_cond: bool): try: if raise_exc: print("raising exception") raise Exception print("not raising exception") finally: if enter_finally_cond: print("in finally conditional") print("after finally") try: example(raise_exc=True, enter_finally_cond=True) except: passWhen traced under 3.11:
% python3.11 -m trace --trace test.py --- modulename: test, funcname: <module> test.py(1): import sys test.py(2): print(sys.version) 3.11.4 (main, Jun 7 2023, 08:42:37) [Clang 14.0.3 (clang-1403.0.22.14.1)] test.py(4): def example(raise_exc: bool, enter_finally_cond: bool): test.py(16): try: test.py(17): example(raise_exc=True, enter_finally_cond=True) --- modulename: test, funcname: example test.py(5): try: test.py(6): if raise_exc: test.py(7): print("raising exception") raising exception test.py(8): raise Exception test.py(11): if enter_finally_cond: test.py(12): print("in finally conditional") in finally conditional test.py(18): except: test.py(19): pass When traced under 3.12:
% python3.12 -m trace --trace test.py --- modulename: test, funcname: <module> test.py(1): import sys test.py(2): print(sys.version) 3.12.0b2 (main, Jun 7 2023, 08:47:18) [Clang 14.0.3 (clang-1403.0.22.14.1)] test.py(4): def example(raise_exc: bool, enter_finally_cond: bool): test.py(16): try: test.py(17): example(raise_exc=True, enter_finally_cond=True) --- modulename: test, funcname: example test.py(5): try: test.py(6): if raise_exc: test.py(7): print("raising exception") raising exception test.py(8): raise Exception test.py(11): if enter_finally_cond: test.py(12): print("in finally conditional") in finally conditional test.py(11): if enter_finally_cond: # <****** test.py(18): except: test.py(19): pass The extra line is marked with <******. There's no reason for the if statement to be traced again.