fix(eslint-plugin-query): prevent Object.prototype false positives in no-unstable-deps

.changeset/fix-no-unstable-deps-prototype-lookup.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/eslint-plugin-query': patch
+---
+
+Fix false positive in `no-unstable-deps` when a variable is assigned from a call whose name matches an `Object.prototype` method (e.g. `toString`, `valueOf`, `constructor`).

packages/eslint-plugin-query/src/__tests__/no-unstable-deps.test.ts

@@ -405,3 +405,29 @@ reactHookNames.forEach((reactHookName) => {
     },
   )
 })
+
+const protoMethodNames = [
+  'toString',
+  'valueOf',
+  'constructor',
+  'hasOwnProperty',
+  'isPrototypeOf',
+  'propertyIsEnumerable',
+  'toLocaleString',
+] as const
+
+ruleTester.run('no-unstable-deps', rule, {
+  valid: protoMethodNames.map((method) => ({
+    name: `should not flag variable from "${method}()" call as unstable dep`,
+    code: `
+      import { useCallback } from "React";
+
+      function Component() {
+        const result = ${method}();
+        const cb = useCallback(() => { result }, [result]);
+        return null;
+      }
+    `,
+  })),
+  invalid: [],
+})

packages/eslint-plugin-query/src/rules/no-unstable-deps/no-unstable-deps.rule.ts

@@ -139,7 +139,10 @@ export const rule = createRule({
       }
 
       if (callExpression.callee.type === AST_NODE_TYPES.Identifier) {
-        return trackedCustomHooks[callExpression.callee.name]
+        const calleeName = callExpression.callee.name
+        return Object.hasOwn(trackedCustomHooks, calleeName)
+          ? trackedCustomHooks[calleeName]
+          : undefined
       }
 
       return undefined