René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"PEP 669: for loop fires LINE multiple times for body, but only one for `for`","articleBody":"I'm experimenting with the new monitoring interface in PEP 669. The LINE event happens multiple times for the line in the body of a for loop (as I expect), but the for statement itself only gets an event on entering, not each time around the loop.\r\n\r\nThis code:\r\n```python\r\nimport sys\r\n\r\ndef loop3():\r\n    for i in range(3):\r\n        print(i)\r\n    print(\"done\")\r\n\r\nthe_code = loop3.__code__\r\n\r\ndef line_callback(code, line_number):\r\n    assert code == the_code\r\n    print(f\"LINE: {line_number}\")\r\n\r\nmy_id = sys.monitoring.COVERAGE_ID\r\nsys.monitoring.use_tool_id(my_id, \"repro\")\r\nsys.monitoring.register_callback(my_id, sys.monitoring.events.LINE, line_callback)\r\nsys.monitoring.set_local_events(my_id, the_code, sys.monitoring.events.LINE)\r\n\r\nloop3()\r\n```\r\nproduces:\r\n```\r\nLINE: 4\r\nLINE: 5\r\n0\r\nLINE: 5\r\n1\r\nLINE: 5\r\n2\r\nLINE: 6\r\ndone\r\n```\r\nI would expect Line 4 to be monitored after each \"LINE: 5\", including after the last one.\r\n\r\nThis is with commit 263abd333d of CPython.","author":{"url":"https://github.com/nedbat","@type":"Person","name":"nedbat"},"datePublished":"2023-05-06T16:34:00.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":13},"url":"https://github.com/104239/cpython/issues/104239"}