fix: fast refresh stops on needed bail outs (facebook#11105)

packages/react-dev-utils/webpackHotDevClient.js

@@ -230,6 +230,18 @@ function canApplyUpdates() {
   return module.hot.status() === 'idle';
 }
 
+function canAcceptErrors() {
+  // NOTE: This var is injected by Webpack's DefinePlugin, and is a boolean instead of string.
+  const hasReactRefresh = process.env.FAST_REFRESH;
+
+  const status = module.hot.status();
+  // React refresh can handle hot-reloading over errors.
+  // However, when hot-reload status is abort or fail,
+  // it indicates the current update cannot be applied safely,
+  // and thus we should bail out to a forced reload for consistency.
+  return hasReactRefresh && ["abort", "fail"].indexOf(status) === -1
+}
+
 // Attempt to update code on the fly, fall back to a hard reload.
 function tryApplyUpdates(onHotUpdateSuccess) {
   if (!module.hot) {
@@ -243,11 +255,13 @@ function tryApplyUpdates(onHotUpdateSuccess) {
   }
 
   function handleApplyUpdates(err, updatedModules) {
-    // NOTE: This var is injected by Webpack's DefinePlugin, and is a boolean instead of string.
-    const hasReactRefresh = process.env.FAST_REFRESH;
-    const wantsForcedReload = err || !updatedModules || hadRuntimeError;
-    // React refresh can handle hot-reloading over errors.
-    if (!hasReactRefresh && wantsForcedReload) {
+    const haveErrors = err || hadRuntimeError;
+    // When there is no error but updatedModules is unavailable,
+    // it indicates a critical failure in hot-reloading,
+    // e.g. server is not ready to serve new bundle,
+    // and hence we need to do a forced reload.
+    const needsForcedReload = !err && !updatedModules;
+    if ((haveErrors && !canAcceptErrors()) || needsForcedReload) {
       window.location.reload();
       return;
     }