feat(rsbuild-plugin): apply the build engine for rslib

`rslib` was left out of the engine entirely, so a library build read none of the
Lynx config and had to mirror the parts it needed by hand.

Apply the engine there too, and skip the plugins that shape or serve a bundle:
`rslib` assembles its own, and `rstest` has none.

Author: upupming

.changeset/rslib-engine.md

@@ -0,0 +1,6 @@
+---
+"@lynx-js/react-rsbuild-plugin": patch
+"@lynx-js/rsbuild-plugin": patch
+---
+
+Apply the Lynx build engine for `rslib` as well, so a library build reads the Lynx config. The plugins that shape or serve a bundle stay off, since `rslib` assembles its own.

packages/rspeedy/plugin-lynx/src/index.ts

@@ -74,26 +74,40 @@ export function isPluginLynxRegistered(
 export function pluginLynx(
   options: LynxPluginOptions = {},
 ): RsbuildPlugin[] {
-  return [
-    {
-      name: PLUGIN_LYNX_NAME,
-      setup() {
-        // A marker, so its presence can be detected. It has no behavior.
-      },
-    },
-    pluginConfig(options),
+  // `rslib` assembles the bundle itself and `rstest` has none.
+  const bundlePlugins = [
     pluginChunkLoading(),
+    pluginLynxDebugMetadata(),
+    pluginOutput(),
+    pluginResolve(),
+    pluginSwc(),
     pluginCssMinimizer(),
     pluginDev(),
-    pluginLynxDebugMetadata(),
     pluginMinify(),
     pluginOptimization(),
-    pluginOutput(),
-    pluginResolve(),
     pluginServer(),
     pluginSourcemap(),
-    pluginSwc(),
     pluginTarget(),
+  ].map((plugin): RsbuildPlugin => ({
+    ...plugin,
+    setup(api) {
+      const { callerName } = api.context
+      if (callerName === 'rslib' || callerName === 'rstest') {
+        return
+      }
+      return plugin.setup(api)
+    },
+  }))
+
+  return [
+    {
+      name: PLUGIN_LYNX_NAME,
+      setup() {
+        // A marker, so its presence can be detected. It has no behavior.
+      },
+    },
+    pluginConfig(options),
     pluginTemplate(),
+    ...bundlePlugins,
   ]
 }

packages/rspeedy/plugin-react/src/autoLynx.ts

@@ -6,16 +6,14 @@ import type { RsbuildContext, RsbuildPlugin } from '@rsbuild/core'
 
 import { isPluginLynxRegistered, pluginLynx } from '@lynx-js/rsbuild-plugin'
 
-// Rspeedy applies `pluginLynx` itself. With plain Rsbuild nothing does, so the
-// build engine is applied here.
+// Rspeedy applies `pluginLynx` itself. Nothing does with plain Rsbuild or
+// `rslib`, so the engine is applied here.
 export function pluginAutoLynx(): RsbuildPlugin {
   return {
     name: 'lynx:react:auto-lynx',
     async setup(api) {
-      // The callers that do not emit a Lynx template do not want the engine
-      // either. See the same condition in `applyEntry`.
-      const { callerName } = api.context
-      if (callerName === 'rslib' || callerName === 'rstest') {
+      // A test run has no bundle for the engine to configure.
+      if (api.context.callerName === 'rstest') {
         return
       }
 

packages/rspeedy/plugin-react/src/entry.ts

@@ -87,8 +87,6 @@ export function applyEntry(
     const emitTemplate = api.context.callerName !== 'rslib'
       && api.context.callerName !== 'rstest'
     if (emitTemplate) {
-      // `pluginAutoLynx` applies the engine for the same callers, so the config
-      // is there whenever a template is emitted.
       if (!lynxConfig) {
         throw new Error(
           'No Lynx config exposed. `pluginLynx` has to be applied for the Lynx build engine to be configured.',

packages/rspeedy/plugin-react/test/auto-lynx.test.ts

@@ -165,7 +165,8 @@ describe('pluginAutoLynx', () => {
     }
   })
 
-  test('does not apply the engine for the rslib caller', async () => {
+  test('applies the engine for the rslib caller, minus the bundle it does not own', async () => {
+    let lynxConfig: unknown
     const rsbuild = await createRsbuild({
       callerName: 'rslib',
       // eslint-disable-next-line n/no-unsupported-features/node-builtins
@@ -174,12 +175,25 @@ describe('pluginAutoLynx', () => {
         mode: 'production',
         environments: { lynx: {} },
         source: { entry: { main: './fixtures/basic.tsx' } },
-        plugins: [pluginReactLynx()],
+        plugins: [
+          pluginReactLynx(),
+          {
+            name: 'test:read-lynx-config',
+            setup(api) {
+              api.modifyBundlerChain(() => {
+                lynxConfig = api.useExposed(
+                  Symbol.for('@lynx-js/rsbuild-plugin:config'),
+                )
+              })
+            },
+          } satisfies RsbuildPlugin,
+        ],
       },
     })
 
     const [config] = await rsbuild.initConfigs()
 
+    expect(lynxConfig).toBeDefined()
     expect(
       config?.plugins?.some(plugin =>
         plugin?.constructor.name === 'LynxTemplatePlugin'