Strange Behavior Python 3.8 Walrus Operator: chained inequalities

Question

The following code:

a,b=1,2
print((x:=a)<2<(z:=b) or z>1>x)
print((x:=a)<1<(y:=b) or y>1>x)

gives the following output:

False
Traceback (most recent call last):
  File "C:/Users/phili/PycharmProjects/ML 1/CodingBat exercises.py", line 56, in <module>
    print((x:=a)<1<(y:=b) or y>1>x)
NameError: name 'y' is not defined

which seems absolutely inconsistent. Some variations like (x:=1)>=2>(y:=9) or y>=2>x also gives

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'y' is not defined

Does anyone know what's happening?

Answer 1

Apparently chained operators short-circuit. You can see this in this example code:

>>> 1 < 1 < print("Nope")
False  # Nothing else is printed

This is likely because

a < b < c

Is essentially a short-hand of

a < b and b < c

And and short-circuits:

>>> False and print("Nope")
False

This means that since the left-hand check is False, the right side is never evaluated, so y is never set.