From 391fb7365e8fa53af5eadf8d673eda1fdda30db9 Mon Sep 17 00:00:00 2001
From: Maxime Bargiel <maximeb@unity3d.com>
Date: Sat, 1 Jun 2019 00:43:31 -0400
Subject: [PATCH] Add heuristics to stats.ino comparison when bigint is not
 available

---
 lib/util/stat.js | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

diff --git a/lib/util/stat.js b/lib/util/stat.js
index 350cb9f7..1361858e 100644
--- a/lib/util/stat.js
+++ b/lib/util/stat.js
@@ -76,7 +76,7 @@ function checkPaths (src, dest, funcName, cb) {
   getStats(src, dest, (err, stats) => {
     if (err) return cb(err)
     const { srcStat, destStat } = stats
-    if (destStat && destStat.ino && destStat.dev && destStat.ino === srcStat.ino && destStat.dev === srcStat.dev) {
+    if (destStat && areIdentical(srcStat, destStat)) {
       return cb(new Error('Source and destination must not be the same.'))
     }
     if (srcStat.isDirectory() && isSrcSubdir(src, dest)) {
@@ -88,7 +88,7 @@ function checkPaths (src, dest, funcName, cb) {
 
 function checkPathsSync (src, dest, funcName) {
   const { srcStat, destStat } = getStatsSync(src, dest)
-  if (destStat && destStat.ino && destStat.dev && destStat.ino === srcStat.ino && destStat.dev === srcStat.dev) {
+  if (destStat && areIdentical(srcStat, destStat)) {
     throw new Error('Source and destination must not be the same.')
   }
   if (srcStat.isDirectory() && isSrcSubdir(src, dest)) {
@@ -111,7 +111,7 @@ function checkParentPaths (src, srcStat, dest, funcName, cb) {
         if (err.code === 'ENOENT') return cb()
         return cb(err)
       }
-      if (destStat.ino && destStat.dev && destStat.ino === srcStat.ino && destStat.dev === srcStat.dev) {
+      if (areIdentical(srcStat, destStat)) {
         return cb(new Error(errMsg(src, dest, funcName)))
       }
       return checkParentPaths(src, srcStat, destParent, funcName, cb)
@@ -122,7 +122,7 @@ function checkParentPaths (src, srcStat, dest, funcName, cb) {
         if (err.code === 'ENOENT') return cb()
         return cb(err)
       }
-      if (destStat.ino && destStat.dev && destStat.ino === srcStat.ino && destStat.dev === srcStat.dev) {
+      if (areIdentical(srcStat, destStat)) {
         return cb(new Error(errMsg(src, dest, funcName)))
       }
       return checkParentPaths(src, srcStat, destParent, funcName, cb)
@@ -145,12 +145,35 @@ function checkParentPathsSync (src, srcStat, dest, funcName) {
     if (err.code === 'ENOENT') return
     throw err
   }
-  if (destStat.ino && destStat.dev && destStat.ino === srcStat.ino && destStat.dev === srcStat.dev) {
+  if (areIdentical(srcStat, destStat)) {
     throw new Error(errMsg(src, dest, funcName))
   }
   return checkParentPathsSync(src, srcStat, destParent, funcName)
 }
 
+function areIdentical (srcStat, destStat) {
+  if (destStat.ino && destStat.dev && destStat.ino === srcStat.ino && destStat.dev === srcStat.dev) {
+    if (nodeSupportsBigInt() || destStat.ino < Number.MAX_SAFE_INTEGER) {
+      // definitive answer
+      return true
+    }
+    // Use additional heuristics if we can't use 'bigint'.
+    // Different 'ino' could be represented the same if they are >= Number.MAX_SAFE_INTEGER
+    // See issue 657
+    if (destStat.size === srcStat.size &&
+        destStat.mode === srcStat.mode &&
+        destStat.nlink === srcStat.nlink &&
+        destStat.atimeMs === srcStat.atimeMs &&
+        destStat.mtimeMs === srcStat.mtimeMs &&
+        destStat.ctimeMs === srcStat.ctimeMs &&
+        destStat.birthtimeMs === srcStat.birthtimeMs) {
+      // heuristic answer
+      return true
+    }
+  }
+  return false
+}
+
 // return true if dest is a subdir of src, otherwise false.
 // It only checks the path strings.
 function isSrcSubdir (src, dest) {