"npm test" fails with EPERM at fs.exists() on Windows

[seaoak]

Check List

Please check followings before submitting a new issue.

• I have already read Docs page & Troubleshooting page
• I have already searched existing issues and they are not help to me
• I examined error or warning messages and it's difficult to solve
• Using the latest version of Hexo (run hexo version to check)
• Node.js is higher than 8.6.0

Expected behavior

npm test command passes.

Actual behavior

npm test command fails with Error: EPERM: operation not permitted as follows:

This error is caused by calling fs.exists() for db.json.
The file db.json is removed (unlinked) immediately before.

How to reproduce?

$ git checkout master
$ npm test

Environment

OS: Windows 10 64bit (rev.1909)
Node.js: v12.16.2, v14.1.0, v10.20.1
AntiVirus: none (use "Windows Defender")

Source codes:

$ git log --oneline --decorate -1
2b63f9fc (HEAD -> master, upstream/master) perf(post): simplify codeblock escape (#4254)
$
$ (cd ../hexo-util && git log --oneline --decorate -1)
f5d510a (HEAD -> master, upstream/master, origin/master, origin/HEAD) Merge pull request #199 from curbengh/cache-class
$
$ (cd ../hexo-fs && git log --oneline --decorate -1) | cat
c0a4b6c (HEAD -> master, upstream/master, origin/master, origin/HEAD) ci(appveyor): stop updating npm (#68)
$

[seaoak]

As a trial, I inserted delay (100ms) between fs.unlink() and fs.exists().
The result is OK (two test cases of "Save database" pass).
So I think this issue might be related to race condition of file operation.

diff --git a/test/scripts/filters/save_database.js b/test/scripts/filters/save_database.js
index d6a38368..9180f75a 100644
--- a/test/scripts/filters/save_database.js
+++ b/test/scripts/filters/save_database.js
@@ -3,6 +3,12 @@
 const { exists, unlink } = require('hexo-fs');
 const Promise = require('bluebird');

+const sleep = async (period_ms) => {
+  return new Promise(resolve => {
+    setTimeout(() => resolve(), period_ms);
+  });
+};
+
 describe('Save database', () => {
   const Hexo = require('../../../lib/hexo');
   const hexo = new Hexo();
@@ -17,7 +23,8 @@ describe('Save database', () => {
     const exist = await exists(dbPath);
     exist.should.be.true;

-    unlink(dbPath);
+    await unlink(dbPath);
+    await sleep(100);
   });

   it('do nothing if hexo is not initialized', async () => {

[seaoak]

Before hexo-fs 3.0.0, the EPERM error at fs.access() in fs.exists() was discarded.
I think this is because this issue comes to the surface now.

[seaoak]

This issue seems to be resolved by the PR #4322

[SukkaW]

This issue seems to be resolved by the PR #4322

Ref: hexojs/warehouse#81