From 160957353bbb827f2932dcbe052418d306bcf440 Mon Sep 17 00:00:00 2001
From: Matthew Costabile <mattcosta7@github.com>
Date: Mon, 6 Jul 2026 16:29:14 +0000
Subject: [PATCH] React Compiler migration prep: REACT_COMPILER_ALL flag + skip
 test/story files; remove dead react-compiler eslint override

---
 eslint.config.mjs                        | 15 +++++++--------
 packages/react/script/react-compiler.mjs | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/eslint.config.mjs b/eslint.config.mjs
index 37c4c0adeb0..ca1c13a5651 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -12,7 +12,6 @@ import react from 'eslint-plugin-react'
 import reactHooks from 'eslint-plugin-react-hooks'
 import reactRefreshPlugin from 'eslint-plugin-react-refresh'
 import reactYouMightNotNeedAnEffect from 'eslint-plugin-react-you-might-not-need-an-effect'
-import {unsupportedPatterns as reactCompilerUnsupported} from './packages/react/script/react-compiler.mjs'
 import playwright from 'eslint-plugin-playwright'
 import prettierRecommended from 'eslint-plugin-prettier/recommended'
 import primerReact from 'eslint-plugin-primer-react'
@@ -77,13 +76,13 @@ const config = defineConfig([
       ],
     },
   },
-  // Disable react-compiler rule for files not yet migrated
-  {
-    files: reactCompilerUnsupported.map(p => `packages/react/${p}`),
-    rules: {
-      'react-compiler/react-compiler': 'off',
-    },
-  },
+  // Note: React Compiler lint diagnostics are enforced repo-wide by
+  // eslint-plugin-react-hooks `recommended-latest` (the granular `react-hooks/*`
+  // rules, e.g. `set-state-in-effect`, `immutability`, `refs`, `purity`). The old
+  // monolithic `react-compiler/react-compiler` rule no longer exists (that plugin
+  // is not installed), so there is no per-file compiler-rule override here. Which
+  // files actually get compiled/memoized is gated separately by `isSupported` in
+  // packages/react/script/react-compiler.mjs.
 
   ...fixupConfigRules([github.browser, github.recommended, github.react]),
 
diff --git a/packages/react/script/react-compiler.mjs b/packages/react/script/react-compiler.mjs
index 184c468cfc0..a575285f925 100644
--- a/packages/react/script/react-compiler.mjs
+++ b/packages/react/script/react-compiler.mjs
@@ -58,6 +58,21 @@ const unsupported = new Set(
 )
 
 function isSupported(filepath) {
+  // Never compile test or story files: they aren't shipped, often define ad-hoc
+  // helper components that violate the Rules of React (which makes the compiler
+  // inject hooks into non-components and throw "invalid hook call"), and gain
+  // nothing from memoization. Excluding them also keeps a component's test suite
+  // green when the component itself is migrated.
+  if (/\.(test|stories)\.[cm]?[jt]sx?$/.test(filepath)) {
+    return false
+  }
+  // Opt-in override to compile ALL (non-test) source files, including the
+  // not-yet-migrated ones, so the full test suite can validate a bulk React
+  // Compiler migration. Enable with REACT_COMPILER_ALL=true
+  // (e.g. `REACT_COMPILER_ALL=true npm test`).
+  if (process.env.REACT_COMPILER_ALL === 'true') {
+    return true
+  }
   return !unsupported.has(filepath)
 }