Redis/INCR

When you ( Outcome: error. Key is still absent because RPOPing the last element out of a list nullifies it.

Scenario 2: Key is an integer
Outcome: key incremented.

Scenario 3: Key is a list
Outcome: error. Key is unmodified, because RPUSH and RPOP are each other’s inverse.

Scenario 4: Key is some other type
Outcome: error.