From c9207d86856de0b96a98fe95abb5a14b341c9c70 Mon Sep 17 00:00:00 2001
From: Vladimir Agafonkin <agafonkin@gmail.com>
Date: Tue, 7 Feb 2017 17:43:47 +0200
Subject: [PATCH 1/2] optimize buildActionsForCopy routine

---
 src/util/fs.js | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/src/util/fs.js b/src/util/fs.js
index 957b999fe0..5e4a311579 100644
--- a/src/util/fs.js
+++ b/src/util/fs.js
@@ -144,21 +144,24 @@ async function buildActionsForCopy(
       srcFiles = await readdir(src);
     }
 
-    if (await exists(dest)) {
-      const destStat = await lstat(dest);
+    let destStat;
+    try {
+      destStat = await lstat(dest);
+    } catch (e) {}
 
+    if (destStat) {
       const bothSymlinks = srcStat.isSymbolicLink() && destStat.isSymbolicLink();
       const bothFolders = srcStat.isDirectory() && destStat.isDirectory();
       const bothFiles = srcStat.isFile() && destStat.isFile();
 
-      if (srcStat.mode !== destStat.mode) {
-        try {
-          await access(dest, srcStat.mode);
-        } catch (err) {
-          // EINVAL access errors sometimes happen which shouldn't because node shouldn't be giving
-          // us modes that aren't valid. investigate this, it's generally safe to proceed.
-        }
-      }
+      // EINVAL access errors sometimes happen which shouldn't because node shouldn't be giving
+      // us modes that aren't valid. investigate this, it's generally safe to proceed.
+
+      // if (srcStat.mode !== destStat.mode) {
+      //   try {
+      //     await access(dest, srcStat.mode);
+      //   } catch (err) {}
+      // }
 
       if (bothFiles && srcStat.size === destStat.size && +srcStat.mtime === +destStat.mtime) {
         // we can safely assume this is the same file
@@ -186,12 +189,6 @@ async function buildActionsForCopy(
           if (srcFiles.indexOf(file) < 0) {
             const loc = path.join(dest, file);
             possibleExtraneous.add(loc);
-
-            if ((await lstat(loc)).isDirectory()) {
-              for (const file of await readdir(loc)) {
-                possibleExtraneous.add(path.join(loc, file));
-              }
-            }
           }
         }
       }
@@ -207,8 +204,10 @@ async function buildActionsForCopy(
       });
       onDone();
     } else if (srcStat.isDirectory()) {
-      reporter.verbose(reporter.lang('verboseFileFolder', dest));
-      await mkdirp(dest);
+      if (!destStat) {
+        reporter.verbose(reporter.lang('verboseFileFolder', dest));
+        await mkdirp(dest);
+      }
 
       const destParts = dest.split(path.sep);
       while (destParts.length) {

From d77af5037f46f0ae85991f80757ee7f5e6a5a92c Mon Sep 17 00:00:00 2001
From: Vladimir Agafonkin <agafonkin@gmail.com>
Date: Thu, 9 Feb 2017 14:00:31 +0200
Subject: [PATCH 2/2] more resilient sync in util.fs, add comments

---
 src/util/fs.js | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/util/fs.js b/src/util/fs.js
index 5e4a311579..dce58aa78a 100644
--- a/src/util/fs.js
+++ b/src/util/fs.js
@@ -146,9 +146,14 @@ async function buildActionsForCopy(
 
     let destStat;
     try {
+      // try accessing the destination
       destStat = await lstat(dest);
-    } catch (e) {}
+    } catch (e) {
+      // proceed if destination doesn't exist, otherwise error
+      if (e.code !== 'ENOENT') throw e;
+    }
 
+    // if destination exists
     if (destStat) {
       const bothSymlinks = srcStat.isSymbolicLink() && destStat.isSymbolicLink();
       const bothFolders = srcStat.isDirectory() && destStat.isDirectory();
@@ -157,11 +162,11 @@ async function buildActionsForCopy(
       // EINVAL access errors sometimes happen which shouldn't because node shouldn't be giving
       // us modes that aren't valid. investigate this, it's generally safe to proceed.
 
-      // if (srcStat.mode !== destStat.mode) {
-      //   try {
-      //     await access(dest, srcStat.mode);
-      //   } catch (err) {}
-      // }
+      /* if (srcStat.mode !== destStat.mode) {
+        try {
+          await access(dest, srcStat.mode);
+        } catch (err) {}
+      } */
 
       if (bothFiles && srcStat.size === destStat.size && +srcStat.mtime === +destStat.mtime) {
         // we can safely assume this is the same file