From 8d9f363ed973ae23d331bed98b5b42e88de03088 Mon Sep 17 00:00:00 2001
From: Steve Mao <maochenyan@gmail.com>
Date: Mon, 3 Aug 2015 23:06:22 +1000
Subject: [PATCH] fix(previousTag): incase there is no commits in the first
 release

---
 index.js     |  4 ++--
 test/test.js | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/index.js b/index.js
index 84b5fc049..70442346b 100644
--- a/index.js
+++ b/index.js
@@ -184,9 +184,9 @@ function conventinalChangelog(options, context, gitRawCommitsOpts, parserOpts, w
 
               if (!previousTag) {
                 if (options.append) {
-                  context.previousTag = context.previousTag || commits[0].hash;
+                  context.previousTag = context.previousTag || commits[0] ? commits[0].hash : null;
                 } else {
-                  context.previousTag = context.previousTag || commits[commits.length - 1].hash;
+                  context.previousTag = context.previousTag || commits[commits.length - 1] ? commits[commits.length - 1].hash : null;
                 }
               }
             } else {
diff --git a/test/test.js b/test/test.js
index 4c2eecf93..e48bb9bd7 100644
--- a/test/test.js
+++ b/test/test.js
@@ -399,6 +399,73 @@ describe('conventionalChangelog', function() {
           done();
         }));
     });
+
+    it('should still work if first release has no commits (prepend)', function(done) {
+      shell.exec('git tag v0.0.1 ' + tail);
+      var i = 0;
+
+      conventionalChangelog({
+        releaseCount: 0
+      }, {
+        version: '3.0.0'
+      }, {}, {}, {
+        mainTemplate: '{{previousTag}}...{{currentTag}}',
+        transform: function() {
+          return null;
+        }
+      })
+        .pipe(through(function(chunk, enc, cb) {
+          chunk = chunk.toString();
+
+          if (i === 0) {
+            expect(chunk).to.equal('v2.0.0...v3.0.0');
+          } else if (i === 1) {
+            expect(chunk).to.equal('v0.0.1...v2.0.0');
+          } else if (i === 2) {
+            expect(chunk).to.equal('...v0.0.1');
+          }
+
+          i++;
+          cb();
+        }, function() {
+          expect(i).to.equal(3);
+          done();
+        }));
+    });
+
+    it('should still work if first release has no commits (append)', function(done) {
+      shell.exec('git tag v0.0.1 ' + tail);
+      var i = 0;
+
+      conventionalChangelog({
+        releaseCount: 0,
+        append: true
+      }, {
+        version: '3.0.0'
+      }, {}, {}, {
+        mainTemplate: '{{previousTag}}...{{currentTag}}',
+        transform: function() {
+          return null;
+        }
+      })
+        .pipe(through(function(chunk, enc, cb) {
+          chunk = chunk.toString();
+
+          if (i === 0) {
+            expect(chunk).to.equal('...v0.0.1');
+          } else if (i === 1) {
+            expect(chunk).to.equal('v0.0.1...v2.0.0');
+          } else if (i === 2) {
+            expect(chunk).to.equal('v2.0.0...v3.0.0');
+          }
+
+          i++;
+          cb();
+        }, function() {
+          expect(i).to.equal(3);
+          done();
+        }));
+    });
   });
 
   it('should warn if preset is not found', function(done) {