René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"3.12 tracing regression: a conditional in a finally block will revisit the condition before exiting the block.","articleBody":"Python 3.12 introduced a change in tracing behavior.  Now a conditional in a finally block will revisit the condition before exiting the block.\r\n\r\nHere is test.py:\r\n```python\r\nimport sys\r\nprint(sys.version)\r\n\r\ndef example(raise_exc: bool, enter_finally_cond: bool):\r\n    try:\r\n        if raise_exc:\r\n            print(\"raising exception\")\r\n            raise Exception\r\n        print(\"not raising exception\")\r\n    finally:\r\n        if enter_finally_cond:\r\n            print(\"in finally conditional\")\r\n\r\n    print(\"after finally\")\r\n\r\ntry:\r\n    example(raise_exc=True, enter_finally_cond=True)\r\nexcept:\r\n    pass\r\n```\r\n\r\nWhen traced under 3.11:\r\n```\r\n% python3.11 -m trace --trace test.py\r\n --- modulename: test, funcname: \u003cmodule\u003e\r\ntest.py(1): import sys\r\ntest.py(2): print(sys.version)\r\n3.11.4 (main, Jun  7 2023, 08:42:37) [Clang 14.0.3 (clang-1403.0.22.14.1)]\r\ntest.py(4): def example(raise_exc: bool, enter_finally_cond: bool):\r\ntest.py(16): try:\r\ntest.py(17):     example(raise_exc=True, enter_finally_cond=True)\r\n --- modulename: test, funcname: example\r\ntest.py(5):     try:\r\ntest.py(6):         if raise_exc:\r\ntest.py(7):             print(\"raising exception\")\r\nraising exception\r\ntest.py(8):             raise Exception\r\ntest.py(11):         if enter_finally_cond:\r\ntest.py(12):             print(\"in finally conditional\")\r\nin finally conditional\r\ntest.py(18): except:\r\ntest.py(19):     pass\r\n```\r\n\r\nWhen traced under 3.12:\r\n```\r\n% python3.12 -m trace --trace test.py\r\n --- modulename: test, funcname: \u003cmodule\u003e\r\ntest.py(1): import sys\r\ntest.py(2): print(sys.version)\r\n3.12.0b2 (main, Jun  7 2023, 08:47:18) [Clang 14.0.3 (clang-1403.0.22.14.1)]\r\ntest.py(4): def example(raise_exc: bool, enter_finally_cond: bool):\r\ntest.py(16): try:\r\ntest.py(17):     example(raise_exc=True, enter_finally_cond=True)\r\n --- modulename: test, funcname: example\r\ntest.py(5):     try:\r\ntest.py(6):         if raise_exc:\r\ntest.py(7):             print(\"raising exception\")\r\nraising exception\r\ntest.py(8):             raise Exception\r\ntest.py(11):         if enter_finally_cond:\r\ntest.py(12):             print(\"in finally conditional\")\r\nin finally conditional\r\ntest.py(11):         if enter_finally_cond:             # \u003c******\r\ntest.py(18): except:\r\ntest.py(19):     pass\r\n```\r\n\r\nThe extra line is marked with `\u003c******`.  There's no reason for the if statement to be traced again.\r\n\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-109384\n* gh-109411\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/nedbat","@type":"Person","name":"nedbat"},"datePublished":"2023-06-11T18:33:38.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/105658/cpython/issues/105658"}