fix(node-resolve): resolve symlinked entry point properly (rollup#291)

The regression appeared here uuidjs/uuid#402 (comment)
after upgrading from `rollup-plugin-node-resolve` to `@rollup/plugin-node-solve`

Dependencies entry points are resolved into symlinked path when browser
field map contains paths resolved into real paths.

Author: TrySound

packages/node-resolve/src/util.js

@@ -171,7 +171,12 @@ export function resolveImportSpecifiers(importSpecifierList, resolveOptions) {
         return value;
       }
 
-      return resolveId(importSpecifierList[i], resolveOptions);
+      return resolveId(importSpecifierList[i], resolveOptions).then((result) => {
+        if (!resolveOptions.preserveSymlinks) {
+          result = realpathSync(result);
+        }
+        return result;
+      });
     });
 
     if (i < importSpecifierList.length - 1) {

packages/node-resolve/test/fixtures/symlinked/second/index.browser.js

@@ -0,0 +1 @@
+export default 'not random string';

packages/node-resolve/test/fixtures/symlinked/second/package.json

@@ -0,0 +1,7 @@
+{
+  "name": "second",
+  "main": "./index.js",
+  "browser": {
+    "./index.js": "./index.browser.js"
+  }
+}

packages/node-resolve/test/symlinks.js

@@ -53,6 +53,16 @@ test.serial('resolves symlinked packages', async (t) => {
   t.is(module.exports.number1, module.exports.number2);
 });
 
+test.serial('resolves symlinked packages with browser object', async (t) => {
+  const bundle = await rollup({
+    input: 'symlinked/first/index.js',
+    onwarn: () => t.fail('No warnings were expected'),
+    plugins: [nodeResolve({ browser: true })]
+  });
+  const { module } = await testBundle(t, bundle);
+  t.is(module.exports.number1, 'not random string');
+});
+
 test.serial('preserves symlinks if `preserveSymlinks` is true', async (t) => {
   const bundle = await rollup({
     input: 'symlinked/first/index.js',