Refactor CONSUME_MULTIPLE_SEGMENTS in BaseConverter

[davetapley]

I was going to add types to

falcon/falcon/routing/converters.py

Line 34 in 4910dd7

class BaseConverter(metaclass=abc.ABCMeta):

but as the docs give the type of value ⬇️ depend on CONSUME_MULTIPLE_SEGMENTS.

falcon/falcon/routing/converters.py

Lines 46 to 53 in 4910dd7

	def convert(self, value):
	"""Convert a URI template field value to another format or type.
	Args:
	value (str or List[str]): Original string to convert.
	If ``CONSUME_MULTIPLE_SEGMENTS=True`` this value is a
	list of strings containing the path segments matched by
	the converter.

This is a bit awkward because CONSUME_MULTIPLE_SEGMENTS can only be known at run time, but it's so tightly coupled to the behavior of the class it feels like it should be static.

Can I propose having two classes instead, e.g. BaseConverter and BaseConverterMultipleSegment, with value as str and list[str] respectively?

Then we could probably get rid of ⬇️ and just do an isinstance check.

falcon/falcon/routing/converters.py

Lines 61 to 62 in 4910dd7

	def _consumes_multiple_segments(converter):
	return getattr(converter, 'CONSUME_MULTIPLE_SEGMENTS', False)

[CaselIT]

Hi,

The main reason for the current design is that converters for historical reason do not need to be subclasses of BaseConverter, but ducktyping is used.

I'm not opposed to changing the requirement to have them being a sublcass of BaseConverter and BaseConverterMultipleSegment but it would likely be a v5 since it would be nicer if v4 would just raise deprecation warnings for this.