From c57f7ffc3ffb8ab828b9032ce6effb477dc5cc30 Mon Sep 17 00:00:00 2001
From: Loilo <florian.reuschel@gmx.de>
Date: Fri, 6 Apr 2018 10:17:04 +0200
Subject: [PATCH] Allow dead symlinks for source/destination, fixes #829

---
 src/ln.js  | 21 +++++++++++++++++++--
 test/ln.js | 21 +++++++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/ln.js b/src/ln.js
index 867cc775..f1f4a73f 100644
--- a/src/ln.js
+++ b/src/ln.js
@@ -39,7 +39,15 @@ function _ln(options, source, dest) {
     dest = path.join(dest, path.basename(sourcePath));
   }
 
-  if (fs.existsSync(dest)) {
+  var destinationExists;
+  try {
+    fs.lstatSync(dest);
+    destinationExists = true;
+  } catch (err) {
+    destinationExists = false;
+  }
+
+  if (destinationExists) {
     if (!options.force) {
       common.error('Destination file exists', { continue: true });
     }
@@ -51,7 +59,16 @@ function _ln(options, source, dest) {
     var isWindows = process.platform === 'win32';
     var linkType = isWindows ? 'file' : null;
     var resolvedSourcePath = isAbsolute ? sourcePath : path.resolve(process.cwd(), path.dirname(dest), source);
-    if (!fs.existsSync(resolvedSourcePath)) {
+
+    var resolvedSourceExists;
+    try {
+      fs.lstatSync(resolvedSourcePath);
+      resolvedSourceExists = true;
+    } catch (err) {
+      resolvedSourceExists = false;
+    }
+
+    if (!resolvedSourceExists) {
       common.error('Source file does not exist', { continue: true });
     } else if (isWindows && common.statFollowLinks(resolvedSourcePath).isDirectory()) {
       linkType = 'junction';
diff --git a/test/ln.js b/test/ln.js
index fee55652..2f00f5a9 100644
--- a/test/ln.js
+++ b/test/ln.js
@@ -157,6 +157,15 @@ test('Inside existing directory', t => {
   );
 });
 
+test('Link to dead source links', t => {
+  shell.cd(t.context.tmp);
+  const result = shell.ln('-s', 'badlink', 'link-to-dead-link');
+  t.is(result.code, 0);
+  t.falsy(result.stderr);
+  t.falsy(shell.error());
+  fs.lstatSync('link-to-dead-link');
+});
+
 test('-f option', t => {
   const result = shell.ln('-f', `${t.context.tmp}/file1.js`, `${t.context.tmp}/file2.js`);
   t.is(result.code, 0);
@@ -181,6 +190,18 @@ test('-sf option', t => {
   });
 });
 
+test('Override dead destination links with -sf', t => {
+  shell.cd(t.context.tmp);
+  const result = shell.ln('-sf', 'file1.txt', 'badlink');
+  t.is(result.code, 0);
+  t.falsy(result.stderr);
+  t.falsy(shell.error());
+  t.is(
+    fs.readFileSync('file1.txt').toString(),
+    fs.readFileSync('badlink').toString()
+  );
+});
+
 test('Abspath regression', t => {
   utils.skipOnWinForEPERM(shell.ln.bind(shell, '-sf', 'file1', path.resolve(`${t.context.tmp}/abspath`)), () => {
     t.truthy(fs.existsSync(`${t.context.tmp}/abspath`));