From affd060e003a582678ee1f27ee9a3b5638cc0041 Mon Sep 17 00:00:00 2001
From: Dan Abramov <gaearon@fb.com>
Date: Tue, 25 Jun 2019 03:21:53 -0700
Subject: [PATCH] Fix module push/pop tracking

Reviewed By: threepointone, cpojer

Differential Revision: D15983911

fbshipit-source-id: 9006b82984f326f4160a7e526552cab250e33efd
---
 packages/metro/src/lib/polyfills/require.js | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/packages/metro/src/lib/polyfills/require.js b/packages/metro/src/lib/polyfills/require.js
index ded992e63a..3941812f33 100644
--- a/packages/metro/src/lib/polyfills/require.js
+++ b/packages/metro/src/lib/polyfills/require.js
@@ -70,8 +70,8 @@ const EMPTY = {};
 const {hasOwnProperty} = {};
 
 if (__DEV__) {
-  var RefreshRegNoop = () => {};
-  var RefreshSigNoop = () => type => type;
+  global.$RefreshReg$ = () => {};
+  global.$RefreshSig$ = () => type => type;
 }
 
 function clear(): ModuleList {
@@ -351,6 +351,8 @@ function loadModuleImplementation(
     if (__DEV__) {
       moduleObject.hot = module.hot;
 
+      var prevRefreshReg = global.$RefreshReg$;
+      var prevRefreshSig = global.$RefreshSig$;
       if (Refresh != null) {
         const RefreshRuntime = Refresh;
         global.$RefreshReg$ = (type, id) => {
@@ -358,9 +360,6 @@ function loadModuleImplementation(
         };
         global.$RefreshSig$ =
           RefreshRuntime.createSignatureFunctionForTransform;
-      } else {
-        global.$RefreshReg$ = RefreshRegNoop;
-        global.$RefreshSig$ = RefreshSigNoop;
       }
     }
     moduleObject.id = moduleId;
@@ -396,8 +395,6 @@ function loadModuleImplementation(
         );
       }
 
-      global.$RefreshReg$ = RefreshRegNoop;
-      global.$RefreshSig$ = RefreshSigNoop;
       if (Refresh != null) {
         const isRefreshBoundary = registerExportsForReactRefresh(
           Refresh,
@@ -427,6 +424,8 @@ function loadModuleImplementation(
           'initializingModuleIds is corrupt; something is terribly wrong',
         );
       }
+      global.$RefreshReg$ = prevRefreshReg;
+      global.$RefreshSig$ = prevRefreshSig;
     }
   }
 }