Logic eval error: stack underflow in bnz

General
,
1

What does the error logic eval error: stack underflow in bnz mean? I’m using pyteal…

2

It means that there is nothing on the stack when you called bnz.
The stack must contain an integer before calling bnz.

For example, this program is incorrect:

#pragma version 5

bnz test

test:
int 1

but this one is correct:

#pragma version 5

int 1
bnz test

test:
int 1
3

What is the most common way to get this error in pyteal?