Support preserveSymlinks: false (fixes #400) (#401)

* Support preserveSymlinks: false (fixes #400)

* remove only

* Promise.prototype.finally is too new

* Only realpath existing paths

* Update appveyor to ensure symlinks are enabled

appveyor.yml

@@ -6,6 +6,7 @@ clone_depth: 10
 
 init:
   - git config --global core.autocrlf false
+  - git config --global core.symlinks true
 
 environment:
   matrix:

src/index.js

@@ -1,3 +1,4 @@
+import { realpathSync, existsSync } from 'fs';
 import { extname, resolve } from 'path';
 import { sync as nodeResolveSync, isCore } from 'resolve';
 import { createFilter } from 'rollup-pluginutils';
@@ -39,8 +40,15 @@ export default function commonjs(options = {}) {
 			} catch (err) {
 				resolvedId = resolve(id);
 			}
-
 			customNamedExports[resolvedId] = options.namedExports[id];
+
+			if (existsSync(resolvedId)) {
+				const realpath = realpathSync(resolvedId);
+				if (realpath !== resolvedId) {
+					customNamedExports[realpath] = options.namedExports[id];
+				}
+			}
+
 		});
 	}
 

test/samples/symlinked-node-modules/index.js

@@ -0,0 +1 @@
+import { foo } from 'events';

test/test.js

@@ -342,6 +342,42 @@ describe('rollup-plugin-commonjs', () => {
 			});
 		});
 
+		it('handles symlinked node_modules with preserveSymlinks: false', () => {
+			const cwd = process.cwd();
+
+			// ensure we resolve starting from a directory with
+			// symlinks in node_modules.
+
+			process.chdir('samples/symlinked-node-modules');
+
+			return rollup({
+				input: './index.js',
+				onwarn(warning) {
+					// should not get a warning about unknown export 'foo'
+					throw new Error(`Unexpected warning: ${warning.message}`);
+				},
+				plugins: [
+					resolve({
+						preserveSymlinks: false,
+						preferBuiltins: false
+					}),
+					commonjs({
+						namedExports: {
+							events: ['foo']
+						}
+					})
+				]
+			})
+				.then(v => {
+					process.chdir(cwd);
+					return v;
+				})
+				.catch(err => {
+					process.chdir(cwd);
+					throw err;
+				});
+		});
+
 		it('handles named exports for built-in shims', async () => {
 			const bundle = await rollup({
 				input: 'samples/custom-named-exports-browser-shims/main.js',