fix: should not rely on runtimeByEntries

packages/runtime/plugin-runtime/src/cli/code.ts

@@ -20,13 +20,6 @@ import { resolveSSRMode } from './ssr/mode';
 import * as template from './template';
 import * as serverTemplate from './template.server';
 
-function getSSRMode(
-  entry: string,
-  config: AppToolsNormalizedConfig,
-): 'string' | 'stream' | false {
-  return resolveSSRMode({ entry, config });
-}
-
 export const generateCode = async (
   entrypoints: Entrypoint[],
   appContext: AppToolsContext,
@@ -45,15 +38,25 @@ export const generateCode = async (
   } = appContext;
   await Promise.all(
     entrypoints.map(async entrypoint => {
-      const { entryName, isAutoMount, entry, customEntry, customServerEntry } =
-        entrypoint;
+      const {
+        entryName,
+        isAutoMount,
+        entry,
+        customEntry,
+        customServerEntry,
+        nestedRoutesEntry,
+      } = entrypoint;
       const { plugins: runtimePlugins } =
         await hooks._internalRuntimePlugins.call({
           entrypoint,
           plugins: [],
         });
       if (isAutoMount) {
-        const ssrMode = getSSRMode(entryName, config);
+        const ssrMode = resolveSSRMode({
+          entry: entryName,
+          config,
+          nestedRoutesEntry,
+        });
         let indexCode = '';
         // index.jsx
         if (!ssrMode && config.server.rsc) {

packages/runtime/plugin-runtime/src/cli/ssr/index.ts

@@ -6,6 +6,7 @@ import type {
   ServerUserConfig,
 } from '@modern-js/app-tools';
 import type { CLIPluginAPI } from '@modern-js/plugin';
+import type { Entrypoint } from '@modern-js/types';
 import { LOADABLE_STATS_FILE, isUseSSRBundle } from '@modern-js/utils';
 import type { RsbuildPlugin } from '@rsbuild/core';
 import { resolveSSRMode } from './mode';
@@ -43,12 +44,32 @@ const hasStringSSREntry = (userConfig: AppToolsNormalizedConfig): boolean => {
   return false;
 };
 
+/**
+ * Check if any entry uses string SSR mode.
+ * Returns true if at least one entry uses 'string' SSR mode.
+ */
 const checkUseStringSSR = (
   config: AppToolsNormalizedConfig,
   appDirectory?: string,
+  entrypoints?: Entrypoint[],
 ): boolean => {
-  const ssrMode = resolveSSRMode({ config, appDirectory });
-  return ssrMode === 'string';
+  // If entrypoints are provided, check each entry
+  if (entrypoints && entrypoints.length > 0) {
+    for (const entrypoint of entrypoints) {
+      const ssrMode = resolveSSRMode({
+        entry: entrypoint.entryName,
+        config,
+        appDirectory,
+        nestedRoutesEntry: entrypoint.nestedRoutesEntry,
+      });
+      if (ssrMode === 'string') {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  return true;
 };
 
 const ssrBuilderPlugin = (
@@ -70,12 +91,12 @@ const ssrBuilderPlugin = (
           : 'node';
 
       const appContext = modernAPI.getAppContext();
-      const { appDirectory } = appContext;
+      const { appDirectory, entrypoints } = appContext;
 
       const useLoadablePlugin =
         isUseSSRBundle(userConfig) &&
         !isServerEnvironment &&
-        checkUseStringSSR(userConfig, appDirectory);
+        checkUseStringSSR(userConfig, appDirectory, entrypoints);
 
       return mergeEnvironmentConfig(config, {
         source: {

packages/runtime/plugin-runtime/src/cli/ssr/mode.ts

@@ -17,8 +17,9 @@ export function resolveSSRMode(params: {
   entry?: string;
   config: AppToolsNormalizedConfig;
   appDirectory?: string;
+  nestedRoutesEntry?: string;
 }): SSRMode {
-  const { entry, config, appDirectory } = params;
+  const { entry, config, appDirectory, nestedRoutesEntry } = params;
 
   // 1. Check if SSG is enabled first (SSG takes precedence over SSR when both are configured)
   const isSsgEnabled =
@@ -29,19 +30,11 @@ export function resolveSSRMode(params: {
         : Object.keys(config.output.ssgByEntries).length > 0));
 
   if (isSsgEnabled) {
-    // If user explicitly disables conventional routing (non-conventional routing), force 'string'
-    const entryRouterConfig = entry
-      ? config.runtimeByEntries?.[entry]?.router
-      : undefined;
-    const routerConfig =
-      entryRouterConfig !== undefined
-        ? entryRouterConfig
-        : config.runtime?.router;
-
-    if (!routerConfig) {
+    if (nestedRoutesEntry) {
+      return 'stream';
+    } else {
       return 'string';
     }
-
     if (appDirectory) {
       return isReact18(appDirectory) ? 'stream' : 'string';
     }

packages/runtime/plugin-runtime/src/router/cli/code/index.ts

@@ -171,6 +171,7 @@ export const generateCode = async (
           entry: entrypoint.entryName,
           config,
           appDirectory: appContext.appDirectory,
+          nestedRoutesEntry: entrypoint.nestedRoutesEntry,
         });
 
         if (ssrMode === 'stream') {