If you’re getting an error that reads “ERR value is out of range, must be positive” in Redis, it’s probably because you’re passing a negative count value to the SPOP command.

To fix this issue, make sure the second argument (if supplied) is a positive value.

Example of Error

Here’s an example of code that produces the above error:

SPOP animals -2

Result:

(error) ERR value is out of range, must be positive

In this case I specified a negative value for the second argument, which resulted in the error.

Solution

To fix the issue, simply make sure the second argument (if supplied) is a positive value:

SPOP animals 2

Result:

1) "Horse"
2) "Zebra"

We can also eliminate the error by omitting the second argument altogether:

SPOP animals

Result:

"Bird"

In this case, only one member is popped.

Passing zero will also eliminate the error, but it will also result in an empty array (i.e. no members will be popped):

SPOP animals 0

Result:

(empty array)

Either way, the solution to ensure that we’re not passing a negative value as the second argument.