From 32ef606678bac055c8a9f473c93ad2e4aca3bf30 Mon Sep 17 00:00:00 2001
From: Joe Savona <joesavona@fb.com>
Date: Wed, 26 Jun 2024 16:06:13 -0700
Subject: [PATCH] [compiler] Add todo fixtures for local reassignment in an
 async callback

[ghstack-poisoned]
---
 ...local-variable-in-async-callback.expect.md | 58 +++++++++++++++++++
 ...assign-local-variable-in-async-callback.js | 16 +++++
 .../packages/snap/src/SproutTodoFilter.ts     |  1 +
 3 files changed, 75 insertions(+)
 create mode 100644 compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo.invalid-reassign-local-variable-in-async-callback.expect.md
 create mode 100644 compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo.invalid-reassign-local-variable-in-async-callback.js

diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo.invalid-reassign-local-variable-in-async-callback.expect.md b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo.invalid-reassign-local-variable-in-async-callback.expect.md
new file mode 100644
index 0000000000000..aa07cce436136
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo.invalid-reassign-local-variable-in-async-callback.expect.md
@@ -0,0 +1,58 @@
+
+## Input
+
+```javascript
+function Component() {
+  let value = null;
+  const reassign = async () => {
+    await foo().then((result) => {
+      // Reassigning a local variable in an async function is *always* mutating
+      // after render, so this should error regardless of where this ends up
+      // getting called
+      value = result;
+    });
+  };
+
+  const onClick = async () => {
+    await reassign();
+  };
+  return <div onClick={onClick}>Click</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+function Component() {
+  const $ = _c(2);
+  let value;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    value = null;
+    $[0] = value;
+  } else {
+    value = $[0];
+  }
+  let t0;
+  if ($[1] === Symbol.for("react.memo_cache_sentinel")) {
+    const reassign = async () => {
+      await foo().then((result) => {
+        value = result;
+      });
+    };
+
+    const onClick = async () => {
+      await reassign();
+    };
+
+    t0 = <div onClick={onClick}>Click</div>;
+    $[1] = t0;
+  } else {
+    t0 = $[1];
+  }
+  return t0;
+}
+
+```
+      
\ No newline at end of file
diff --git a/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo.invalid-reassign-local-variable-in-async-callback.js b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo.invalid-reassign-local-variable-in-async-callback.js
new file mode 100644
index 0000000000000..1ba759e3b8ae7
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo.invalid-reassign-local-variable-in-async-callback.js
@@ -0,0 +1,16 @@
+function Component() {
+  let value = null;
+  const reassign = async () => {
+    await foo().then((result) => {
+      // Reassigning a local variable in an async function is *always* mutating
+      // after render, so this should error regardless of where this ends up
+      // getting called
+      value = result;
+    });
+  };
+
+  const onClick = async () => {
+    await reassign();
+  };
+  return <div onClick={onClick}>Click</div>;
+}
diff --git a/compiler/packages/snap/src/SproutTodoFilter.ts b/compiler/packages/snap/src/SproutTodoFilter.ts
index c4bc6776da784..8d28ba239a368 100644
--- a/compiler/packages/snap/src/SproutTodoFilter.ts
+++ b/compiler/packages/snap/src/SproutTodoFilter.ts
@@ -487,6 +487,7 @@ const skipFilter = new Set([
   "todo.invalid-reassign-local-variable-in-jsx-callback",
   "todo.invalid-reassign-local-variable-in-hook-argument",
   "todo.invalid-reassign-local-variable-in-effect",
+  "todo.invalid-reassign-local-variable-in-async-callback",
 
   // bugs
   "bug-invalid-hoisting-functionexpr",