fix: support reference a scss files which installed to node_modules (#291)

playground/main.js

@@ -2,4 +2,7 @@ import { createApp } from 'vue'
 import App from './App.vue'
 import './testHmrManual'
 
+// test for sass @import
+// import './styles/style.scss'
+
 createApp(App).mount('#app')

playground/package.json

@@ -5,10 +5,11 @@
     "serve": "serve dist"
   },
   "dependencies": {
+    "bootstrap": "^4.5.0",
+    "conditional-exports": "link:./conditional-exports",
     "lodash-es": "link:../node_modules/lodash-es",
     "moment": "link:../node_modules/moment",
-    "rewrite-optimized-test-package": "link:./rewrite-optimized/test-package",
     "resolve-browser-field-test-package": "link:./resolve-browser-field",
-    "conditional-exports": "link:./conditional-exports"
+    "rewrite-optimized-test-package": "link:./rewrite-optimized/test-package"
   }
 }

playground/styles/style.scss

@@ -0,0 +1 @@
+@import 'bootstrap/scss/bootstrap';

playground/yarn.lock

@@ -2,6 +2,11 @@
 # yarn lockfile v1
 
 
+bootstrap@^4.5.0:
+  version "4.5.0"
+  resolved "https://registry.yarnpkg.com/bootstrap/-/bootstrap-4.5.0.tgz#97d9dbcb5a8972f8722c9962483543b907d9b9ec"
+  integrity sha512-Z93QoXvodoVslA+PWNdk23Hze4RBYIkpb5h8I2HY2Tu2h7A0LpAgLcyrhrSUyo2/Oxm2l1fRZPs1e5hnxnliXA==
+
 "conditional-exports@link:./conditional-exports":
   version "0.0.0"
   uid ""

src/node/server/serverPluginModuleRewrite.ts

@@ -254,11 +254,8 @@ export const resolveImport = (
     // 3. resolve extensions.
     const ext = resolver.resolveExt(pathname)
     if (ext) {
-      pathname += ext
-      if (ext[0] === '/') {
-        // in aliased cases the inferred ext can contain multiple slashes
-        pathname = pathname.replace(/\/\/+/g, '/')
-      }
+      // in aliased cases the inferred ext can contain multiple slashes
+      pathname = path.posix.normalize(pathname + ext)
     }
 
     // 4. mark non-src imports

src/node/utils/cssUtils.ts

@@ -78,7 +78,10 @@ export async function compileCss(
           postcssOptions: postcssConfig.options,
           postcssPlugins: postcssConfig.plugins
         }
-      : {})
+      : {}),
+    preprocessOptions: {
+      includePaths: ['node_modules']
+    }
   })
 }