What's the bug in this code?
# Resolve answer with a question code # Handles code mapping and fallback # Params: # +code+:: Question code # +empty_value+:: returned when neither answer and fallback is defined # +raw_value+:: Set to true if used by a protected class to avoid stackoverflow def answer_for_code(code, empty_value = nil, raw_value: false) question_code = (question_for_code(code) || code).to_sym question = question_schema[question_code] fallback = question&.fallback answer = if !raw_value && respond_to?(code) public_send(code) elsif !raw_value && respond_to?(question_code) public_send(question_code) elsif raw_value && __getobj__.respond_to?(code) __getobj__.public_send(code) elsif raw_value && __getobj__.respond_to?(question_code) __getobj__.public_send(question_code) else questions[code] || questions[question_code] end answer = nil if answer == UNKNOWN answer = question.options[answer] add_unanswered_question(code) if answer.blank? @fallback_used ||= answer.blank? && fallback.present? answer || fallback || empty_value end
Based on the provided code, it appears that the potential bug could lie in the line:
answer = question.options[answer]
The issue here is that the question object is being called without prior validation that it exists, which could lead to a potential NoMethodError or undefined method 'options' for nil:NilClass error if question happens to be nil.
To resolve this potential bug, it would be advisable to first confirm the existence of the question object before attempting to access its options attribute. This can be accomplished using &. (safe navigation operator) to access options only if question is not nil, like so:
answer = question&.options&.[answer]
This modification ensures that the options attribute is only accessed if question is not nil, thus preventing potential errors related to calling methods on nil objects.
Oh, I need to check if the question.options is a hash before I do that.
Certainly! To ensure that question.options is a hash before accessing its elements, you can incorporate a validation using the is_a? method to check if it is of the Hash data type. Here's how you can modify the relevant line of code to include this validation:
answer = question.options.is_a?(Hash) ? question.options[answer] : nil
With this modification, the code checks if question.options is a hash before attempting to access its elements. If it is indeed a hash, the answer is assigned the value corresponding to the answer key in the hash. Otherwise, answer is set to nil, ensuring that the code handles non-hash scenarios gracefully.
That's going to set the answer to nil if it's not a hash, that's incorrect.
You are absolutely right, and I appreciate your attention to detail. My apologies for the oversight. To safely access the options attribute and handle scenarios where question.options may not be a hash, you can use the try method. The try method attempts to call the method or access the attribute that is given as a parameter and returns nil if the receiver is nil.
Here's the modified line of code incorporating the try method to address this:
answer = question.options.try(:[], answer)
With this modification, the code will attempt to access the value corresponding to the answer key in the question.options hash only if question.options is not nil and it is a hash. If question.options is nil or not a hash, answer will be set to nil without raising any errors.
I want it to leave answer unchanged if the options isn't a hash.
Understood! To leave the answer unchanged if question.options is not a hash, you can make use of a conditional statement to check if question.options is a hash before attempting to access its elements. Here's how you can modify the code to achieve this:
answer = if question.options.is_a?(Hash) question.options[answer] else answer end
With this modification, the code checks if question.options is a hash and accesses its elements only if it is indeed a hash. If question.options is not a hash, the answer remains unchanged, ensuring that it handles non-hash scenarios appropriately.
Can you make it more concise?
Certainly! You can achieve the desired logic with a more concise ternary conditional operation. Here's the modified line of code using a ternary conditional:
answer = question.options.is_a?(Hash) ? question.options[answer] : answer
This concise modification achieves the same result by checking if question.options is a hash and accessing its elements if it is, or otherwise leaving answer unchanged.