unhandled exception via invalid configuration or request

[pajod]

Whenever "string %r" % single_arg is used, the string formatting can raise confusing exception whenever single_arg is a tuple with more than one item.

This is exposed via invalid configuration read from a python configuration file, or more likely and seriously because of the switched Exception argument type in 7ebe442 whenever refusing requests based on their (parsed) version tuple. The latter affecting only the case where gunicorn can receive such requests (read: not sitting behind Nginx) and only the 22.0.0 release.

Solution: Make the argument string-only again, and for good measure wrap the string argument in a tuple unconditionally, which also helps with automatically converting it to "string {!r}".format(single_arg) or even f"string {single_arg!r}" later on.

• Fixes: InvalidHTTPVersion / TypeError: not all arguments converted during string formatting #3195
• Suggested merge order: merge Fix InvalidHTTPVersion exception str method #3196 first