Add new Lint/HashCompareByIdentity cop
#8796
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fatkodima
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Thank you for the implementation. I was also considering this style rule implementation. Cc @rubocop-hq/rubocop-core |
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I ❤️ it when a cop improves our own code base 🎉
Even though both cases deal with comparing by identity, I wonder if we shouldn't split this into two cops:
- Some people might not like
compare_by_identityand want to disable that (but not the use ofequal? - The
==case is safe (I think 😅), the second case is not quite safe: although unlikely, the hash could store object ids and other stuff that need be compared by values.
Maybe @bbatsov has an opinion on this
Edit: Just read @koic's remark, glad to see we agree about splitting this 😄
| return unless receiver && argument | ||
| def_node_matcher :id_comparison?, <<~PATTERN | ||
| (send | ||
| (send $!nil? :object_id) :== |
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Why the !nil?? We should still replace object_id == other.object_id with equal?(other), and other.object_id == object_id with other.equal?(self) no?
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| replacement = "#{receiver.source}.equal?(#{argument.source})" | ||
| def_node_matcher :id_as_hash_key?, <<~PATTERN | ||
| (send _ {:key? :has_key? :fetch :[] :[]=} (send !nil? :object_id) ...) |
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Same here: hash[object_id] should be an offense
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I ❤️ it when a cop improves our own code base 🎉
Even though both cases deal with comparing by identity, I wonder if we shouldn't split this into two cops:
- Some people might not like
compare_by_identityand want to disable that (but not the use ofequal? - The
==case is safe (I think 😅), the second case is not quite safe: although unlikely, the hash could store object ids and other stuff that need be compared by values.
fatkodima
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Extracted into a separate cop. |
fatkodima
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Lint/IdentityComparison cop with a rule for object_id as hash keysLint/CompareByIdentity cop
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fatkodima
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Lint/CompareByIdentity copLint/HashCompareByIdentity cop
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Thanks! |
This implements a second part of https://rubystyle.guide/#identity-comparison