fix: Execute HMR reload only when basePath it's the same as request handler

Author: agustints

packages/next/src/server/lib/router-server.ts

@@ -583,13 +583,20 @@ export async function initialize(opts: {
       })
 
       if (opts.dev && developmentBundler && req.url) {
-        const isHMRRequest = req.url.includes('/_next/webpack-hmr')
+        const { basePath } = config
+
+        const isHMRRequestForHostApp =
+          !basePath && req.url.startsWith('/_next/webpack-hmr')
+
+        const isHMRRequestForGuestApp =
+          basePath && pathHasPrefix(req.url, basePath)
+
+        const isHMRRequestForCurrentBasepath =
+          isHMRRequestForHostApp || isHMRRequestForGuestApp
+
         // only handle HMR requests if the basePath in the request
         // matches the basePath for the handler responding to the request
-        const isRequestForCurrentBasepath =
-          !config.basePath || pathHasPrefix(req.url, config.basePath)
-
-        if (isHMRRequest && isRequestForCurrentBasepath) {
+        if (isHMRRequestForCurrentBasepath) {
           return developmentBundler.hotReloader.onHMR(req, socket, head)
         }
       }