Quick Answer
The answer is that the script include's function signature changed. This is the most likely cause of undefined errors after a ServiceNow upgrade because when a script include is defined as a public static function and called from multiple business rules, any alteration to its parameters, return type, or method name breaks the existing calls, resulting in the system returning undefined instead of a value. On the ServiceNow Certified Application Developer CAD exam, this scenario tests your understanding of how script includes are compiled and cached; a common trap is confusing undefined errors with not found errors, which would occur if the script include itself was missing. Remember that ACLs do not block server-side execution, and scope changes typically cause access errors, not undefined. A helpful memory tip is to think "signature mismatch equals undefined output" because the calling code expects a specific function contract that no longer exists.
This SNOW-CAD practice question tests your understanding of automating application logic with business rules and scripts. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A script include is defined as a public static function and is called from multiple business rules. After an upgrade, some business rules start failing with 'undefined' errors. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
The script include was made private.
Why wrong: Would cause 'cannot access' error, not undefined.
The script include's ACLs changed.
Why wrong: ACLs do not affect server-side script execution.
The script include's function signature changed.
Function parameter count or name change leads to undefined errors on call.
The script include's scope changed.
Why wrong: Scope change causes access issues, not undefined.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The script include's function signature changed.
Option D is correct because if the function signature changed, calls to it would fail with 'undefined' errors. Option A would cause 'not found' errors, not undefined. Option B ACLs do not affect server-side execution. Option C scope change could cause issues but typically results in access errors, not undefined.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The script include was made private.
Why it's wrong here
Would cause 'cannot access' error, not undefined.
The script include's ACLs changed.
Why it's wrong here
ACLs do not affect server-side script execution.
The script include's function signature changed.
Why this is correct
Function parameter count or name change leads to undefined errors on call.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
The script include's scope changed.
Why it's wrong here
Scope change causes access issues, not undefined.
Common exam traps
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SNOW-CAD NAT questions on configuration and troubleshooting.
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FAQ
Automating application logic with business rules and scripts — This question tests Automating application logic with business rules and scripts — Static NAT maps one inside address to one outside address..
The correct answer is: The script include's function signature changed. — Option D is correct because if the function signature changed, calls to it would fail with 'undefined' errors. Option A would cause 'not found' errors, not undefined. Option B ACLs do not affect server-side execution. Option C scope change could cause issues but typically results in access errors, not undefined.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SNOW-CAD NAT questions on configuration and troubleshooting.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Static NAT maps one inside address to one outside address.
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Last reviewed: Jun 24, 2026
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