About `permutations()`, setting the longer length than `iterable` argument to `r` argument returns nothing, error should be returned for this

[hyperkai]

Bug report

Bug description:

About permutations(), setting the longer length than iterable argument to r argument returns nothing as shown below. *In this example, setting 1, 2 and 3 to r argument returns values:

from itertools import permutations

for x in permutations(iterable='ABC', r=4):
    print(x)
# Nothing

So for this, the error like below should be returned:

ValueError: r must be 0 <= x < = iterable length

from itertools import permutations

for x in permutations(iterable='ABC', r=4):
    print(x)
# Nothing

CPython versions tested on:

3.13

Operating systems tested on:

Windows

[tim-one]

I expect this is intentional behavior: if r is greater than the length of the iterable, then there simply are no results of length r to deliver. The docs imply this, although a bit indirectly:

. The length of the output is given by math.perm() which computes n! / (n - r)! when 0 ≤ r ≤ n or zero when r > n.

Note the tail end "zero when r > n".

[skirpichev]

It is also documented by "equivalent" code.

No doubts it's intentional and I don't this it worth to be changed.