copy & copySync: do not overwrite src & dest paths to avoid side effe…

…cts (#554)

lib/copy-sync/copy-sync.js

@@ -23,11 +23,8 @@ function copySync (src, dest, opts) {
     see https://github.com/jprichardson/node-fs-extra/issues/269`)
   }
 
-  src = path.resolve(src)
-  dest = path.resolve(dest)
-
   // don't allow src and dest to be the same
-  if (src === dest) throw new Error('Source and destination must not be the same.')
+  if (path.resolve(src) === path.resolve(dest)) throw new Error('Source and destination must not be the same.')
 
   if (opts.filter && !opts.filter(src, dest)) return
 
@@ -175,15 +172,15 @@ function copyLink (resolvedSrcPath, dest) {
   return fs.symlinkSync(resolvedSrcPath, dest)
 }
 
-// check if dest exists and/or is a symlink
+// check if dest exists and is a symlink.
 function checkDest (dest) {
   let resolvedPath
   try {
     resolvedPath = fs.readlinkSync(dest)
   } catch (err) {
     if (err.code === 'ENOENT') return notExist
 
-    // dest exists and is a regular file or directory, Windows may throw UNKNOWN error
+    // dest exists and is a regular file or directory, Windows may throw UNKNOWN error.
     if (err.code === 'EINVAL' || err.code === 'UNKNOWN') return existsReg
 
     throw err
@@ -192,10 +189,10 @@ function checkDest (dest) {
 }
 
 // return true if dest is a subdir of src, otherwise false.
-// extract dest base dir and check if that is the same as src basename
+// extract dest base dir and check if that is the same as src basename.
 function isSrcSubdir (src, dest) {
-  let srcArray = src.split(path.sep)
-  let destArray = dest.split(path.sep)
+  let srcArray = path.resolve(src).split(path.sep)
+  let destArray = path.resolve(dest).split(path.sep)
 
   return srcArray.reduce((acc, current, i) => {
     return acc && destArray[i] === current

lib/copy/copy.js

@@ -29,11 +29,8 @@ function copy (src, dest, opts, cb) {
     see https://github.com/jprichardson/node-fs-extra/issues/269`)
   }
 
-  src = path.resolve(src)
-  dest = path.resolve(dest)
-
   // don't allow src and dest to be the same
-  if (src === dest) return cb(new Error('Source and destination must not be the same.'))
+  if (path.resolve(src) === path.resolve(dest)) return cb(new Error('Source and destination must not be the same.'))
 
   if (opts.filter) return handleFilter(checkParentDir, src, dest, opts, cb)
   return checkParentDir(src, dest, opts, cb)
@@ -57,11 +54,10 @@ function startCopy (src, dest, opts, cb) {
 }
 
 function handleFilter (onInclude, src, dest, opts, cb) {
-  Promise.resolve(opts.filter(src, dest))
-    .then(include => {
-      if (include) return onInclude(src, dest, opts, cb)
-      return cb()
-    }, error => cb(error))
+  Promise.resolve(opts.filter(src, dest)).then(include => {
+    if (include) return onInclude(src, dest, opts, cb)
+    return cb()
+  }, error => cb(error))
 }
 
 function getStats (src, dest, opts, cb) {
@@ -114,13 +110,12 @@ function copyFile (srcStat, src, dest, opts, cb) {
 
 function copyFileFallback (srcStat, src, dest, opts, cb) {
   const rs = fs.createReadStream(src)
-  rs.on('error', err => cb(err))
-    .once('open', () => {
-      const ws = fs.createWriteStream(dest, { mode: srcStat.mode })
-      ws.on('error', err => cb(err))
-        .on('open', () => rs.pipe(ws))
-        .once('close', () => setDestModeAndTimestamps(srcStat, dest, opts, cb))
-    })
+  rs.on('error', err => cb(err)).once('open', () => {
+    const ws = fs.createWriteStream(dest, { mode: srcStat.mode })
+    ws.on('error', err => cb(err))
+      .on('open', () => rs.pipe(ws))
+      .once('close', () => setDestModeAndTimestamps(srcStat, dest, opts, cb))
+  })
 }
 
 function setDestModeAndTimestamps (srcStat, dest, opts, cb) {
@@ -232,7 +227,7 @@ function copyLink (resolvedSrcPath, dest, cb) {
   })
 }
 
-// check if dest exists and/or is a symlink
+// check if dest exists and is a symlink.
 function checkDest (dest, cb) {
   fs.readlink(dest, (err, resolvedPath) => {
     if (err) {
@@ -248,10 +243,10 @@ function checkDest (dest, cb) {
 }
 
 // return true if dest is a subdir of src, otherwise false.
-// extract dest base dir and check if that is the same as src basename
+// extract dest base dir and check if that is the same as src basename.
 function isSrcSubdir (src, dest) {
-  let srcArray = src.split(path.sep)
-  let destArray = dest.split(path.sep)
+  let srcArray = path.resolve(src).split(path.sep)
+  let destArray = path.resolve(dest).split(path.sep)
 
   return srcArray.reduce((acc, current, i) => {
     return acc && destArray[i] === current