feat: restart dev server on config changes

.gitignore

@@ -6,6 +6,7 @@
 # Dist
 node_modules
 dist/
+dist-*/
 test-results
 doc_build
 

packages/rstack/src/config.ts

@@ -1,4 +1,4 @@
-import { loadConfig } from '@rstackjs/load-config';
+import { loadConfig, type LoadConfigResult } from '@rstackjs/load-config';
 import type { RsbuildConfigDefinition } from '@rsbuild/core';
 import type { RslibConfigDefinition } from '@rslib/core';
 import type { RslintConfig } from '@rslint/core';
@@ -18,6 +18,10 @@ export type Configs = {
   staged?: StagedConfig;
 };
 
+type LoadedRstackConfig = Pick<LoadConfigResult, 'filePath' | 'dependencies'> & {
+  configs: Configs;
+};
+
 type ConfigState = {
   configs: Configs;
   configPath?: string;
@@ -101,12 +105,12 @@ export const define: Define = {
   staged: (config) => setConfig('staged', config),
 };
 
-export const loadRstackConfig = async (): Promise<Configs> => {
+export const loadRstackConfig = async (): Promise<LoadedRstackConfig> => {
   const state = getConfigState();
   state.configs = {};
 
   try {
-    await loadConfig({
+    const { filePath, dependencies } = await loadConfig({
       loader: 'native',
       exportName: false,
       fresh: true,
@@ -122,7 +126,11 @@ export const loadRstackConfig = async (): Promise<Configs> => {
           }),
     });
 
-    return state.configs;
+    return {
+      configs: state.configs,
+      filePath,
+      dependencies,
+    };
   } finally {
     state.configs = {};
   }

packages/rstack/src/rsbuildConfig.ts

@@ -1,4 +1,4 @@
-import type { RsbuildConfigDefinition, ConfigParams } from '@rsbuild/core';
+import { mergeRsbuildConfig, type RsbuildConfigDefinition, type ConfigParams } from '@rsbuild/core';
 import { loadRstackConfig, type Configs } from './config.js';
 
 const resolveRsbuildConfig = async (configs: Configs, params: ConfigParams) => {
@@ -13,8 +13,21 @@ const resolveRsbuildConfig = async (configs: Configs, params: ConfigParams) => {
 };
 
 const loadRsbuildConfig: RsbuildConfigDefinition = async (params) => {
-  const configs = await loadRstackConfig();
-  return resolveRsbuildConfig(configs, params);
+  const { configs, filePath, dependencies } = await loadRstackConfig();
+  const config = await resolveRsbuildConfig(configs, params);
+
+  if (!filePath) {
+    return config;
+  }
+
+  return mergeRsbuildConfig(config, {
+    dev: {
+      watchFiles: {
+        paths: [filePath, ...dependencies],
+        type: 'reload-server',
+      },
+    },
+  });
 };
 
 export default loadRsbuildConfig;

packages/rstack/src/rslibConfig.ts

@@ -14,7 +14,7 @@ const resolveRslibConfig = async (configs: Configs, params: ConfigParams): Promi
 };
 
 const loadRslibConfig = (async (params: ConfigParams) => {
-  const configs = await loadRstackConfig();
+  const { configs } = await loadRstackConfig();
   return resolveRslibConfig(configs, params);
 }) as RslibConfigDefinition;
 

packages/rstack/src/rslintConfig.ts

@@ -1,7 +1,7 @@
 import { loadRstackConfig } from './config.js';
 import type { RslintConfig } from '@rslint/core';
 
-const configs = await loadRstackConfig();
+const { configs } = await loadRstackConfig();
 const lintExports = configs.lint ?? [];
 
 let lintConfig: RslintConfig;

packages/rstack/src/rspressConfig.ts

@@ -13,6 +13,6 @@ const resolveRspressConfig = async (configs: Configs): Promise<UserConfig> => {
 };
 
 export default async (): Promise<UserConfig> => {
-  const configs = await loadRstackConfig();
+  const { configs } = await loadRstackConfig();
   return resolveRspressConfig(configs);
 };

packages/rstack/src/rstestConfig.ts

@@ -56,7 +56,7 @@ const resolveRstestConfig = async (configs: Configs) => {
 };
 
 const loadRstestConfig = (async (params: ConfigParams) => {
-  const configs = await loadRstackConfig();
+  const { configs } = await loadRstackConfig();
   const testConfig = await resolveRstestConfig(configs);
   return extendsConfig(configs, testConfig, params);
 }) as RstestConfigExport;

packages/rstack/src/staged.ts

@@ -65,7 +65,7 @@ export async function runStagedCLI(args: string[]): Promise<void> {
     return;
   }
 
-  const configs = await loadRstackConfig();
+  const { configs } = await loadRstackConfig();
   const stagedConfig = configs.staged;
   if (!stagedConfig) {
     throw new Error(

packages/rstack/test/config/reload-app-config/index.test.ts

@@ -0,0 +1,50 @@
+import { rm, writeFile } from 'node:fs/promises';
+import path from 'node:path';
+import { expectFile, getRandomPort, test } from '#test-helpers';
+
+test('should restart dev server and reload config when Rstack config changes', async ({
+  execCliAsync,
+}) => {
+  const dist1 = path.join(import.meta.dirname, 'dist');
+  const dist2 = path.join(import.meta.dirname, 'dist-2');
+  const configFile = path.join(import.meta.dirname, 'test-temp-rstack.config.ts');
+
+  await rm(dist1, { recursive: true, force: true });
+  await rm(dist2, { recursive: true, force: true });
+  await rm(configFile, { force: true });
+
+  await writeFile(
+    configFile,
+    `import { define } from 'rstack';
+
+define.app({
+  dev: {
+    writeToDisk: true,
+  },
+  server: { port: ${await getRandomPort()} },
+});
+`,
+  );
+
+  execCliAsync('dev --config test-temp-rstack.config.ts');
+
+  await expectFile(dist1);
+
+  await writeFile(
+    configFile,
+    `import { define } from 'rstack';
+
+define.app({
+  dev: {
+    writeToDisk: true,
+  },
+  output: {
+    distPath: 'dist-2',
+  },
+  server: { port: ${await getRandomPort()} },
+});
+`,
+  );
+
+  await expectFile(dist2);
+}, 30_000);

packages/rstack/test/config/reload-app-config/src/index.js

@@ -0,0 +1 @@
+console.log('hello!');