From 6a245f943eb1a5d18cd624e127fb4924b5d1662e Mon Sep 17 00:00:00 2001
From: Dominic Griesel <dominic.griesel@nabucasa.com>
Date: Tue, 6 Sep 2022 13:14:49 +0200
Subject: [PATCH] fix: consider locks acquired in the future to be stale

---
 lib/lockfile.js   |  4 +++-
 test/lock.test.js | 13 +++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/lib/lockfile.js b/lib/lockfile.js
index 97b6637..8e67f34 100644
--- a/lib/lockfile.js
+++ b/lib/lockfile.js
@@ -82,7 +82,9 @@ function acquireLock(file, options, callback) {
 }
 
 function isLockStale(stat, options) {
-    return stat.mtime.getTime() < Date.now() - options.stale;
+    // On some systems it can happen that the time is rewinded after a hard reboot
+    // This would leave us with a lock that seems to be held at a future time.
+    return Math.abs(Date.now() - stat.mtime.getTime()) > options.stale;
 }
 
 function removeLock(file, options, callback) {
diff --git a/test/lock.test.js b/test/lock.test.js
index ec4accb..fc22336 100644
--- a/test/lock.test.js
+++ b/test/lock.test.js
@@ -183,6 +183,19 @@ it('should remove and acquire over stale locks', async () => {
     expect(fs.statSync(`${tmpDir}/foo.lock`).mtime.getTime()).toBeGreaterThan(Date.now() - 3000);
 });
 
+it('should remove and acquire locks from the future', async () => {
+    const mtime = new Date(Date.now() + 60000);
+
+    fs.writeFileSync(`${tmpDir}/foo`, '');
+    fs.mkdirSync(`${tmpDir}/foo.lock`);
+    fs.utimesSync(`${tmpDir}/foo.lock`, mtime, mtime);
+
+    await lockfile.lock(`${tmpDir}/foo`);
+
+    expect(fs.statSync(`${tmpDir}/foo.lock`).mtime.getTime()).toBeGreaterThan(Date.now() - 3000);
+    expect(fs.statSync(`${tmpDir}/foo.lock`).mtime.getTime()).toBeLessThan(Date.now() + 3000);
+});
+
 it('should retry if the lockfile was removed when verifying staleness', async () => {
     const mtime = new Date(Date.now() - 60000);
     let count = 0;