fix: fix parallel install from local directory (#398)

lib/download/local.js

@@ -3,6 +3,7 @@
 const debug = require('debug')('npminstall:download:local');
 const cp = require('mz/child_process');
 const rimraf = require('mz-modules/rimraf');
+const fse = require('fs-extra');
 const fs = require('mz/fs');
 const path = require('path');
 const chalk = require('chalk');
@@ -31,14 +32,18 @@ module.exports = async (pkg, options) => {
 async function localFolder(filepath, pkg, options) {
   debug(`install ${pkg.name}@${pkg.rawSpec} from local folder ${filepath}`);
   try {
+    // everytime copy to a different directory to avoid parallel install
+    const tmpDir = path.join(options.storeDir, '.tmp', uuid());
+    await utils.mkdirp(tmpDir);
+    await fse.copy(filepath, tmpDir);
     // use npm pack to ensure npmignore/gitignore/package.files work fine
-    const res = await cp.exec('npm pack', { cwd: filepath });
+    const res = await cp.exec('npm pack', { cwd: tmpDir });
     if (res && res[0]) {
-      const tarball = path.join(filepath, res[0].trim());
+      const tarball = path.join(tmpDir, res[0].trim());
       try {
         return await localTarball(tarball, pkg, options);
       } finally {
-        await rimraf(tarball);
+        await rimraf(tmpDir);
       }
     }
   } catch (err) {