feat(rust, python)!: consistently return list of date/datetime from lazy date_range

[MarcoGorelli]

closes #7110

This simplifies the logic, but would be a breaking change, so if accepted, might be better to wait for 0.18 or 1.0?

It also simplifies the logic on the user side (I think) - in all the test cases I found where this is used, it removes an unnecessary .implode call

If reviewing, this is much easier if ignoring whitespace: https://github.com/pola-rs/polars/pull/8513/files?w=1

[ritchie46]

I think we should also take this breaking opportunity to change the default lazy=False to eager=False as this will have most merit in the expression API anyway.

Other than that I agree with these changes. Having a dynamic output type dependent on data size was clearly bad design.

[MarcoGorelli]

sounds good - as a separate PR, right?

will also need to address #8512 - preferably after this PR but before the release, as this PR reduces complexity whereas addressing #8512 would increase it

[ritchie46]

sounds good - as a separate PR, right?

Yeap, that's best it seems.

[MarcoGorelli]

here start is an expression, so it behaves like in the lazy manner

polars/py-polars/polars/functions/eager.py

Lines 657 to 661 in 4f574bc

	if (
	not eager
	or isinstance(start, (str, pl.Expr))
	or isinstance(end, (str, pl.Expr))
	):

[ritchie46]

Thanks. Good that we have a consistent output type now.

[ritchie46]

Thanks. Good that we have a consistent output type now.