[rush] install-run.js: _cleanInstallFolder() fails on Windows

[mikeharder]

Is this a feature or a bug?

• Feature
• Bug

Please describe the actual behavior.
On Windows, the install-run-rush.js script fails with the following error if it needs to call the _cleanInstallFolder() function inside install-run.js:

Error: Error cleaning the package install folder 
(C:\js\common\temp\install-run\@[email protected]): 
Error: EPERM: operation not permitted, rename 
'C:\js\common\temp\install-run\@[email protected]\node_modules' -> 
'C:\js\common\temp\rush-recycler\install-run-1589914852715'

Here's an easy way to repro:

> node common\scripts\install-run-rush.js --help
> del "common\temp\install-run\@[email protected]\installed.flag"
> node common\scripts\install-run-rush.js --help

I believe the root cause is these two lines:

rushstack/common/scripts/install-run.js

Lines 295 to 296 in 50d6655

	const rushRecyclerFolder = _ensureAndJoinPath(rushTempFolder, 'rush-recycler', `install-run-${Date.now().toString()}`);
	fs.renameSync(nodeModulesFolder, rushRecyclerFolder);

The first line creates the rushRecyclerFolder, and the second line tries to rename nodeModulesFolder to rushRecyclerFolder. The problem is Windows doesn't allow renaming a folder to an existing folder name.

I see two possible solutions:

1. Delete rushRecyclerFolder before the rename:

fs.rmdirSync(rushRecyclerFolder);
fs.renameSync(nodeModulesFolder, rushRecyclerFolder);

2. Rename nodeModulesFolder to a sub-folder under rushRecyclerFolder. Something like:

fs.renameSync(nodeModulesFolder, path.join(rushRecyclerFolder, NODE_MODULES_FOLDER_NAME));

@octogonz, @iclanton: I can submit a PR for this. Do you prefer fix 1 (rmdir) or fix 2 (rename to subdir)? Are there tests in the repo for install-run.js, so I could add a regression test for this scenario?

Versions

• Tool: Rush
• Tool Version: 5.19.3
• Node Version: 10.20.1
  • Is this a LTS version? yes
  • Have you tested on a LTS version? yes
• OS: Windows 10