fix(compiler): use Object.is() for cache dependency comparison to handle NaN#35885
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fresh3nough wants to merge 2 commits intofacebook:mainfrom
Open
fix(compiler): use Object.is() for cache dependency comparison to handle NaN#35885fresh3nough wants to merge 2 commits intofacebook:mainfrom
fresh3nough wants to merge 2 commits intofacebook:mainfrom
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Fixes #35854
Summary
The React Compiler generates cache dependency checks using strict inequality (
!==), but this produces incorrect behavior forNaNvalues sinceNaN !== NaNis alwaystruein JavaScript. This causes memoized values withNaNdependencies to be recomputed on every render, breaking the memoization guarantee.React's runtime hook dependency comparison (in
areHookInputsEqual) usesObject.is()semantics, which correctly handlesNaN(Object.is(NaN, NaN)returnstrue). The compiler-generated code should be consistent with this behavior.Changes
CodegenReactiveFunction.ts: Changed the dependency comparison codegen from$[n] !== depto!Object.is($[n], dep), which correctly handles bothNaNand-0/+0edge cases, matching the runtime'sObject.issemantics.Before (generated code):
After (generated code):
How to reproduce
Create a component where a dependency evaluates to
NaN:Before this fix, the memoized value would be recomputed on every render because
NaN !== NaNis alwaystrue.Test plan
cache-nan-dependencyfixture that compiles a component with a NaN dependencyyarn prettierandyarn lincwith no issues