From b7a14ecc8d931922b44e92496eedf9710ea3ce39 Mon Sep 17 00:00:00 2001
From: Joe Savona <joesavona@fb.com>
Date: Tue, 3 Oct 2023 09:00:11 -0700
Subject: [PATCH] Detect unknown hooks on React namespace

Handles an edge-case from earlier in the stack. When looking up a property on a
shape, if the property is defined we return it. But if it isn't defined, and the
property name is a hook, we treat it like a default custom hook.
---
 .../src/HIR/Environment.ts                    |  9 +++++---
 .../drop-methodcall-usememo.expect.md         | 17 ++++++++++----
 ...ook-unknown-hook-react-namespace.expect.md | 22 +++++++++++++++++++
 ...ional-hook-unknown-hook-react-namespace.js |  7 ++++++
 4 files changed, 48 insertions(+), 7 deletions(-)
 create mode 100644 compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/error.conditional-hook-unknown-hook-react-namespace.expect.md
 create mode 100644 compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/error.conditional-hook-unknown-hook-react-namespace.js

diff --git a/compiler/packages/babel-plugin-react-forget/src/HIR/Environment.ts b/compiler/packages/babel-plugin-react-forget/src/HIR/Environment.ts
index f0b2298ca4..0e1f2662d5 100644
--- a/compiler/packages/babel-plugin-react-forget/src/HIR/Environment.ts
+++ b/compiler/packages/babel-plugin-react-forget/src/HIR/Environment.ts
@@ -374,9 +374,12 @@ export class Environment {
         loc: null,
         suggestions: null,
       });
-      return (
-        shape.properties.get(property) ?? shape.properties.get("*") ?? null
-      );
+      let value =
+        shape.properties.get(property) ?? shape.properties.get("*") ?? null;
+      if (value === null && isHookName(property)) {
+        value = this.#getCustomHookType();
+      }
+      return value;
     } else if (isHookName(property)) {
       return this.#getCustomHookType();
     } else {
diff --git a/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/drop-methodcall-usememo.expect.md b/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/drop-methodcall-usememo.expect.md
index 84e25bb733..0a1381c761 100644
--- a/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/drop-methodcall-usememo.expect.md
+++ b/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/drop-methodcall-usememo.expect.md
@@ -27,21 +27,30 @@ import { unstable_useMemoCache as useMemoCache } from "react";
 import * as React from "react";
 
 function Component(props) {
-  const $ = useMemoCache(2);
+  const $ = useMemoCache(4);
   const c_0 = $[0] !== props.value;
   let t0;
   if (c_0) {
-    t0 = (() => {
+    t0 = () => {
       const x = [];
       x.push(props.value);
       return x;
-    })();
+    };
     $[0] = props.value;
     $[1] = t0;
   } else {
     t0 = $[1];
   }
-  const x_0 = t0;
+  const c_2 = $[2] !== t0;
+  let t1;
+  if (c_2) {
+    t1 = t0();
+    $[2] = t0;
+    $[3] = t1;
+  } else {
+    t1 = $[3];
+  }
+  const x_0 = t1;
   return x_0;
 }
 
diff --git a/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/error.conditional-hook-unknown-hook-react-namespace.expect.md b/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/error.conditional-hook-unknown-hook-react-namespace.expect.md
new file mode 100644
index 0000000000..8b55ba9e0c
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/error.conditional-hook-unknown-hook-react-namespace.expect.md
@@ -0,0 +1,22 @@
+
+## Input
+
+```javascript
+function Component(props) {
+  let x = null;
+  if (props.cond) {
+    x = React.useNonexistentHook();
+  }
+  return x;
+}
+
+```
+
+
+## Error
+
+```
+[ReactForget] InvalidReact: Hooks must always be called in a consistent order, and may not be called conditionally. See the Rules of Hooks (https://react.dev/warnings/invalid-hook-call-warning) (4:4)
+```
+          
+      
\ No newline at end of file
diff --git a/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/error.conditional-hook-unknown-hook-react-namespace.js b/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/error.conditional-hook-unknown-hook-react-namespace.js
new file mode 100644
index 0000000000..0698132c61
--- /dev/null
+++ b/compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/error.conditional-hook-unknown-hook-react-namespace.js
@@ -0,0 +1,7 @@
+function Component(props) {
+  let x = null;
+  if (props.cond) {
+    x = React.useNonexistentHook();
+  }
+  return x;
+}