Security · interview question

What is the healthiest performance judgment around input validation?

Multiple choiceMediumchapter-17-curatedpremiumsecurityinput-validation

python

def normalize_order_id(order_id: str) -> str:
    if not order_id.startswith("ORD-"):
        raise ValueError("invalid order id")
    return order_id

Measure before optimizing, then change the part that actually dominates cost instead of guessing from style alone.Delay clarity until production traffic reveals the edge case and then patch it under pressure.Solve the symptom with comments only and avoid changing the code shape around input validation.Keep input validation implicit so the script stays short and hope the next engineer infers the rule.

Answer and explanation

Correct answer

A. Measure before optimizing, then change the part that actually dominates cost instead of guessing from style alone.

Why

Premature optimization is usually weaker than targeted optimization backed by measurement.

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What is the healthiest performance judgment around input validation?

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