From 15fef933f4a8bd540cfa25bfc794e7ca8687d780 Mon Sep 17 00:00:00 2001
From: Artyom Skrobov <tyomitch@gmail.com>
Date: Wed, 23 Aug 2017 14:09:01 +0100
Subject: [PATCH] Fix: Bad merge when adding new files (#189)

---
 src/patch/apply.js  |  4 ++++
 test/patch/apply.js | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/patch/apply.js b/src/patch/apply.js
index e6509260..e830fc11 100644
--- a/src/patch/apply.js
+++ b/src/patch/apply.js
@@ -85,6 +85,10 @@ export function applyPatch(source, uniDiff, options = {}) {
         toPos = hunk.oldStart + hunk.offset + diffOffset - 1;
     diffOffset += hunk.newLines - hunk.oldLines;
 
+    if (toPos < 0) { // Creating a new file
+      toPos = 0;
+    }
+
     for (let j = 0; j < hunk.lines.length; j++) {
       let line = hunk.lines[j],
           operation = line[0],
diff --git a/test/patch/apply.js b/test/patch/apply.js
index 96ff4703..67965662 100755
--- a/test/patch/apply.js
+++ b/test/patch/apply.js
@@ -461,6 +461,23 @@ describe('patch/apply', function() {
           + 'line5\n');
     });
 
+    it('should create a file', function() {
+      expect(applyPatch('',
+
+          '--- test\theader1\n'
+          + '+++ test\theader2\n'
+          + '@@ -0,0 +1,4 @@\n'
+          + '+line1\n'
+          + '+line2\n'
+          + '+line3\n'
+          + '+line4\n'))
+        .to.equal(
+          'line1\n'
+          + 'line2\n'
+          + 'line3\n'
+          + 'line4\n');
+    });
+
     it('should erase a file', function() {
       expect(applyPatch(
           'line1\n'