Objects/object.c places tp_name into TypeError and AttributeError exception messages via an inconsistent mess of %.50s, %.100s, and %.200s PyErr_FromFormat format string specifiers.

We butt heads with this at work routinely. Especially on the mere 50 character limit cases. When wrapping C++ classes within a deep directory tree or namespace the .tp_name of the class your pybind11 or otherwise generated extension module code will use can easily be longer than that.

We're going ahead with a local patch to make these consistent with a limit of 200 internally for now, which I'd like to apply here.

But the question arises: What practical reason do we limit the rendered size of tp_name for at all?

Truncating is always the wrong thing to do for information within an error message, the beginning and end of a name string are usually the most unique deterministic parts useful as a debugging aid. If we are to truncate at all rather than just use an unbounded %s format for tp_name we should elide characters from the middle with a ... placeholder. If we don't have a format specifier that can do that for PyUnicodeObject, one would need to be added.

Is there ever a situation where a C PyTypeObject's tp_name can be assigned to an arbitrary length string at runtime?

(There may be places outside of object.c doing this with tp_name as well, I consider finding those and being consistent in approach there part of this issue)

This theme has come up in different areas in the past, but those were for general str/repr of things which are larger cans of worms. Not the tp_name field. For example #57558 and other things generally mentioned via #51579 which added our length specifiers to PyUnicode formatting.