_PropertySetter silently ignores multiple positional arguments

[dangotbanned]

Adapted from #3659 (comment)

What happened?

Minimal Repro

These are all valid:

import altair as alt

valid_scale = alt.Scale(domain=["M", "F"], range=["#1FC3AA", "#8624F5"])

valid_color_1 = alt.Color().scale(valid_scale)
valid_color_2 = alt.Color().scale(domain=["M", "F"], range=["#1FC3AA", "#8624F5"])

Both of these cases naively just ignore everything after the first argument:

alt.Color().scale(["M", "F"], ["#1FC3AA", "#8624F5"])
# Color({
#  scale: ['M', 'F']
#})

alt.Color().scale(valid_scale, valid_scale, valid_scale)
# Color({
#   scale: Scale({
#     domain: ['M', 'F'],
#     range: ['#1FC3AA', '#8624F5']
#   })
# })

Expected

Behavior similar the wrapped class:

invalid_scale = alt.Scale(["M", "F"], ["#1FC3AA", "#8624F5"])

SchemaValidationError: Multiple errors were found.

Error 1: '['M', 'F']' is an invalid value for `align`. Valid values are of type 'number' or 'object'.

Error 2: '['#1FC3AA', '#8624F5']' is an invalid value for `base`. Valid values are of type 'number' or 'object'.

Cause

_PropertySetter.__call__ doesn't align with SchemaBase.__init__:

altair/tools/schemapi/schemapi.py

Lines 1602 to 1606 in 6beec7b

	def __call__(self, *args: Any, **kwargs: Any):
	obj = self.obj.copy()
	# TODO: use schema to validate
	obj[self.prop] = args[0] if args else kwargs
	return obj

Above, we silently drop any positional args after the first (see recording)

Below, we raise an AssertionError if there is more than 1 positional argument

altair/tools/schemapi/schemapi.py

Lines 1018 to 1038 in 6beec7b

	def __init__(self, *args: Any, **kwds: Any) -> None:
	# Two valid options for initialization, which should be handled by
	# derived classes:
	# - a single arg with no kwds, for, e.g. {'type': 'string'}
	# - zero args with zero or more kwds for {'type': 'object'}
	if self._schema is None:
	msg = (
	f"Cannot instantiate object of type {self.__class__}: "
	"_schema class attribute is not defined."
	""
	)
	raise ValueError(msg)
	if kwds:
	assert len(args) == 0
	else:
	assert len(args) in {0, 1}
	# use object.__setattr__ because we override setattr below.
	object.__setattr__(self, "_args", args)
	object.__setattr__(self, "_kwds", kwds)

Note

Appears to have been present in all 5.* versions

What would you like to happen instead?

I think we should raise for all cases that look like this:

alt.ChannelsClass().property_setter(arg1, arg...)

Which version of Altair are you using?

5.5.0dev