René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"warn_explicit() issues a warning or an error when used directly in a script","articleBody":"For example, running the following script:\r\n```py\r\nimport warnings\r\nwarnings.warn_explicit('eggs', UserWarning, 'bar', 1, module_globals=globals())\r\n```\r\nemits a warning:\r\n```\r\n$ ./python t.py\r\n\u003cfrozen importlib._bootstrap_external\u003e:932: DeprecationWarning: Module globals is missing a __spec__.loader\r\n/home/serhiy/py/cpython3.13/t.py:1: UserWarning: eggs\r\n  import warnings\r\n```\r\n\r\nRunning it as a module produces an error:\r\n```\r\n$ ./python -m t\r\nTraceback (most recent call last):\r\n  File \"/home/serhiy/py/cpython3.13/Lib/runpy.py\", line 198, in _run_module_as_main\r\n    return _run_code(code, main_globals, None,\r\n                     \"__main__\", mod_spec)\r\n  File \"/home/serhiy/py/cpython3.13/Lib/runpy.py\", line 88, in _run_code\r\n    exec(code, run_globals)\r\n    ~~~~^^^^^^^^^^^^^^^^^^^\r\n  File \"/home/serhiy/py/cpython3.13/t.py\", line 2, in \u003cmodule\u003e\r\n    warnings.warn_explicit('eggs', UserWarning, __file__, 1, module_globals=globals())\r\n    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\r\n  File \"\u003cfrozen importlib._bootstrap_external\u003e\", line 1073, in get_source\r\n  File \"\u003cfrozen importlib._bootstrap_external\u003e\", line 674, in _check_name_wrapper\r\nImportError: loader for t cannot handle __main__\r\n```\r\n\r\nRunning it in the REPL produces similar error:\r\n```pycon\r\n\u003e\u003e\u003e import warnings\r\n... warnings.warn_explicit('eggs', UserWarning, 'bar', 1, module_globals=globals())\r\n... \r\nTraceback (most recent call last):\r\n  File \"\u003cpython-input-0\u003e\", line 2, in \u003cmodule\u003e\r\n    warnings.warn_explicit('eggs', UserWarning, 'bar', 1, module_globals=globals())\r\n    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\r\n  File \"\u003cfrozen importlib._bootstrap_external\u003e\", line 1073, in get_source\r\n  File \"\u003cfrozen importlib._bootstrap_external\u003e\", line 674, in _check_name_wrapper\r\nImportError: loader for _pyrepl.__main__ cannot handle __main__\r\n```\r\n\r\nBut importing it as a module is OK:\r\n```pycon\r\n\u003e\u003e\u003e import t\r\n/home/serhiy/py/cpython3.13/t.py:1: UserWarning: eggs\r\n  import warnings\r\n```\r\n\r\nThe warning was introduced in #86298, but I think that it was for modules created in non-standard way. Running Python code as a script is pretty standard, this is not a user error. We should handle this case specially.\r\n\r\ncc @brettcannon, @warsaw","author":{"url":"https://github.com/serhiy-storchaka","@type":"Person","name":"serhiy-storchaka"},"datePublished":"2024-08-14T13:50:59.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/123011/cpython/issues/123011"}