Bug report

The docstring line length check is performed before the parameter descriptions are added to the docstring:

        max_width = f.docstring_line_width
        summary_len = len(lines[0])
        max_body = max(map(len, lines[1:]))
        ...
        if not parameters_marker_count:
            lines.insert(2, '{parameters}')

So a description of any length is accepted without a warning.

24 functions in the current tree have parameter description lines longer than the limit (the number of too long lines is in parentheses):

• _lzma.LZMADecompressor (4)
• select.epoll (3)
• int.to_bytes (2)
• select.kqueue.control (2)
• str.encode (2)
• winreg.SetValueEx (2)
• _sqlite3.Connection.getconfig
• _sqlite3.Connection.setconfig
• _sre.template
• _winapi.RegisterEventSource
• _zstd.ZstdCompressor.set_pledged_input_size
• bytearray.decode
• bytearray.rsplit
• bytearray.split
• bytearray.take_bytes
• bytes.decode
• bytes.rsplit
• bytes.split
• gc.set_debug
• os.timerfd_create
• select.poll.poll
• winreg.ConnectRegistry
• winreg.DeleteTree
• zlib._ZlibDecompressor

This is easy to miss for a cloned function, which inherits the descriptions of the function it clones: bytes.split and bytes.rsplit (and the bytearray pair) both have a 69 character line, and rewrapping the description in bytes.split does not make Argument Clinic report anything for either of them.

This is a leftover of #150285.

Linked PRs

• gh-155228: Check the length of parameter descriptions in Argument Clinic #155251