From a1fa7017f45cf1495588f363340f207a207326c6 Mon Sep 17 00:00:00 2001
From: Alex Hunt <huntie@meta.com>
Date: Thu, 18 Jun 2026 07:58:10 -0700
Subject: [PATCH] Delete interface.js (Flow), relocate __DEV__ global (#57275)

Summary:

`interface.js` was a legacy, Flow-only entry point whose sole content was a bare `declare var __DEV__: boolean;` global, registered as a Flow `[libs]` file.

Relocate into `flow/globals.js`, allowing us to drop this from the package `"files"` (and `"exports"`) list.

Changelog: [Internal]

Differential Revision: D109018822
---
 .flowconfig                          |  1 -
 packages/react-native/flow/global.js |  6 ++++++
 packages/react-native/interface.js   | 21 ---------------------
 packages/react-native/package.json   |  1 -
 4 files changed, 6 insertions(+), 23 deletions(-)
 delete mode 100644 packages/react-native/interface.js

diff --git a/.flowconfig b/.flowconfig
index 3a23617f8124..58ca3c06ee61 100644
--- a/.flowconfig
+++ b/.flowconfig
@@ -39,7 +39,6 @@
 
 [libs]
 flow-typed/
-packages/react-native/interface.js
 packages/react-native/flow/
 
 [options]
diff --git a/packages/react-native/flow/global.js b/packages/react-native/flow/global.js
index dc6de666ec02..3082f3fc48c1 100644
--- a/packages/react-native/flow/global.js
+++ b/packages/react-native/flow/global.js
@@ -86,3 +86,9 @@ declare var global: {
   // Undeclared properties are implicitly `any`.
   [string | symbol]: any,
 };
+
+// Declared as a bare global so unqualified `__DEV__` references type-check as
+// `boolean`. The suppression is a no-op in this checkout but avoids a duplicate
+// declaration where `__DEV__` is also declared by another Flow libdef.
+// $FlowFixMe[libdef-override]
+declare var __DEV__: boolean;
diff --git a/packages/react-native/interface.js b/packages/react-native/interface.js
deleted file mode 100644
index b17169a6b153..000000000000
--- a/packages/react-native/interface.js
+++ /dev/null
@@ -1,21 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @flow strict
- * @format
- */
-
-'use strict';
-
-// NOTE: Hmm... I don't think declaring variables within this module actually
-// accomplishes anything besides documenting that these globals are expected to
-// exist. So I think the correct "fix" to this lint warning is to delete this
-// entire file. But in lieu of doing that... no harm for now in keeping this
-// file around, even if it is only for documentation purposes. ¯\_(ツ)_/¯
-
-/* eslint-disable no-unused-vars */
-
-declare var __DEV__: boolean;
diff --git a/packages/react-native/package.json b/packages/react-native/package.json
index 6ea146756613..01ad9377f2c3 100644
--- a/packages/react-native/package.json
+++ b/packages/react-native/package.json
@@ -80,7 +80,6 @@
     "gradle/libs.versions.toml",
     "index.js",
     "index.js.flow",
-    "interface.js",
     "jest-preset.js",
     "Libraries",
     "LICENSE",