What is the order of evaluation for ACL fields?

The order of evaluation for Access Control List (ACL) fields in ServiceNow is crucial for understanding how access permissions are determined. The correct sequence is that the system first checks the "Requires role," then evaluates the "Condition," and finally runs any "Script" that might apply.

When evaluating ACLs, the "Requires role" is checked first because it establishes the fundamental access rights of the user based on the roles they possess. If the user lacks the required roles, the evaluation stops there, and access is denied without progressing further.

Next, the "Condition" field is evaluated. This field allows for more nuanced access control by incorporating conditions that affect whether a user should be granted access. For instance, even if a user has the required roles, specific conditions programmed in this field could further restrict access based on additional parameters like the field values or context of the record being accessed.

Finally, if both the required roles and conditions have been met, the "Script" is executed. This field can implement complex logic to grant or deny access programmatically, allowing for a more detailed and custom access control mechanism.

This order of evaluation is essential for ensuring that the simplest permission checks are handled first before delving into more complicated scripts, enhancing system performance and security