Disable Rails/FindByOrAssignmentMemoization rule #29
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coorasse
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bruno-costanzo,
firemind,
hunchr,
ignaciosy,
odthoma,
rnestler,
schmijos and
sislr
rnestler
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Sep 17, 2025
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rnestler
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Yeah I think it's a subtle thing to be aware of: That the memoization won't work if the query returned nil, but I'm also not sure if the autofix helps a lot, so in favor of disabling it.
sislr
approved these changes
Sep 18, 2025
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A new rule was added to the set, which aims to make memoization more robust when using ActiveRecord's
find_bymethod.It essentially points out cases like this (cobra) and this (fredi), where it aims to ensure that memoization is truly doing what it's intended – ensuring that the query is run only once.
After a short discussion with @coorasse, I'm not sure this subtlety is worth the double (or even worse, 5x) lines of code. Yes, some queries could be ran more than once unnecessarily depending on how often the memoized variable is used, but queries should be cached anyway, which doesn't hinder performance. For this reason, we'd suggest disabling this rule in general.
I personally feel it doesn't bring much to the table, but I'm curious if you see things differently!