René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"PEP 737: PyUnicode_FromFormat(): Add %T format to format the type name of an object","articleBody":"It's common to format a type name by accessing `PyTypeObject.tp_name` member. Example:\r\n\r\n```\r\nPyErr_Format(PyExc_TypeError,\r\n             \"__format__ must return a str, not %.200s\",\r\n             Py_TYPE(result)-\u003etp_name);\r\n```\r\n\r\nProblems:\r\n\r\n* `PyTypeObject.tp_name` (`type.__name__`) is less helpful than `PyHeapTypeObject.ht_qualname` (`type.__qualname__`). I would prefer to display the **qualified** type name.\r\n* `PyTypeObject.tp_name` is a UTF-8 encoded string, it requires to **decode the UTF-8 string** at each call.\r\n* I would like to **remove `PyTypeObject` members (`tp_name`)** from the public C API: issue #105970.\r\n* By the way, in the early days of Python, `PyString_FromFormat()` used a buffer with a fixed size, so the output string should be truncated to avoid overflow. But nowadays, `PyUnicode_FromFormat()` allocates a buffer on the heap and is no longer limited to 200 characters. Truncated a type name can miss important information in the error message. I would prefer to **not truncate** the type name.\r\n\r\nI propose adding a ``%T`` format to PyUnicode_FromUnicode() to format the qualified name of an object type. For example, the example would become:\r\n\r\n```\r\nPyErr_Format(PyExc_TypeError,\r\n             \"__format__ must return a str, not %T\", result);\r\n```\r\n\r\nIn 2018, I already added ``%T`` format to PyUnicode_FromFormat(): issue GH-78776. See related [python-dev discussion](https://mail.python.org/archives/list/python-dev@python.org/thread/HKYUMTVHNBVB5LJNRMZ7TPUQKGKAERCJ/#3UAMHYG6UF4MPLXBZORHO4JVKUBRUZ53). The change was reverted.\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-111703\n* gh-112129\n* gh-112133\n* gh-116815\n* gh-116824\n* gh-116839\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/vstinner","@type":"Person","name":"vstinner"},"datePublished":"2023-11-03T14:51:19.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/111696/cpython/issues/111696"}