diff --git a/generate/templates/manual/patches/convenient_patches.cc b/generate/templates/manual/patches/convenient_patches.cc
index 79823e37a..27de54fcf 100644
--- a/generate/templates/manual/patches/convenient_patches.cc
+++ b/generate/templates/manual/patches/convenient_patches.cc
@@ -95,8 +95,15 @@ void GitPatch::ConvenientFromDiffWorker::HandleOKCallback() {
   }
 
   if (baton->error) {
+    Local<v8::Object> err;
+    if (baton->error->message) {
+      err = Nan::Error(baton->error->message)->ToObject();
+    } else {
+      err = Nan::Error("Method convenientFromDiff has thrown an error.")->ToObject();
+    }
+    err->Set(Nan::New("errno").ToLocalChecked(), Nan::New(baton->error_code));
     Local<v8::Value> argv[1] = {
-      Nan::Error(baton->error->message)
+      err
     };
     callback->Call(1, argv);
     if (baton->error->message)
diff --git a/generate/templates/manual/revwalk/fast_walk.cc b/generate/templates/manual/revwalk/fast_walk.cc
index 2f263f83f..ec3a10cd7 100644
--- a/generate/templates/manual/revwalk/fast_walk.cc
+++ b/generate/templates/manual/revwalk/fast_walk.cc
@@ -88,8 +88,15 @@ void GitRevwalk::FastWalkWorker::HandleOKCallback()
   {
     if (baton->error)
     {
+      Local<v8::Object> err;
+      if (baton->error->message) {
+        err = Nan::Error(baton->error->message)->ToObject();
+      } else {
+        err = Nan::Error("Method fastWalk has thrown an error.")->ToObject();
+      }
+      err->Set(Nan::New("errno").ToLocalChecked(), Nan::New(baton->error_code));
       Local<v8::Value> argv[1] = {
-        Nan::Error(baton->error->message)
+        err
       };
       callback->Call(1, argv);
       if (baton->error->message)
diff --git a/generate/templates/manual/revwalk/file_history_walk.cc b/generate/templates/manual/revwalk/file_history_walk.cc
index 0f511969f..220482679 100644
--- a/generate/templates/manual/revwalk/file_history_walk.cc
+++ b/generate/templates/manual/revwalk/file_history_walk.cc
@@ -289,8 +289,15 @@ void GitRevwalk::FileHistoryWalkWorker::HandleOKCallback()
   }
 
   if (baton->error) {
+    Local<v8::Object> err;
+    if (baton->error->message) {
+      err = Nan::Error(baton->error->message)->ToObject();
+    } else {
+      err = Nan::Error("Method fileHistoryWalk has thrown an error.")->ToObject();
+    }
+    err->Set(Nan::New("errno").ToLocalChecked(), Nan::New(baton->error_code));
     Local<v8::Value> argv[1] = {
-      Nan::Error(baton->error->message)
+      err
     };
     callback->Call(1, argv);
     if (baton->error->message)
diff --git a/generate/templates/partials/async_function.cc b/generate/templates/partials/async_function.cc
index 633ebbfae..b8e19ddb0 100644
--- a/generate/templates/partials/async_function.cc
+++ b/generate/templates/partials/async_function.cc
@@ -155,8 +155,15 @@ void {{ cppClassName }}::{{ cppFunctionName }}Worker::HandleOKCallback() {
     callback->Call(2, argv);
   } else {
     if (baton->error) {
+      v8::Local<v8::Object> err;
+      if (baton->error->message) {
+        err = Nan::Error(baton->error->message)->ToObject();
+      } else {
+        err = Nan::Error("Method {{ jsFunctionName }} has thrown an error.")->ToObject();
+      }
+      err->Set(Nan::New("errno").ToLocalChecked(), Nan::New(baton->error_code));
       v8::Local<v8::Value> argv[1] = {
-        Nan::Error(baton->error->message)
+        err
       };
       callback->Call(1, argv);
       if (baton->error->message)
diff --git a/test/tests/merge.js b/test/tests/merge.js
index 5bf3cb81c..66728bdb9 100644
--- a/test/tests/merge.js
+++ b/test/tests/merge.js
@@ -1612,4 +1612,26 @@ describe("Merge", function() {
         assert.ok(repository.isDefaultState());
       });
   });
+
+  it("can retrieve error code on if common merge base not found", function() {
+    var repo;
+    return NodeGit.Repository.open(local("../repos/workdir"))
+    .then(function(r) {
+      repo = r;
+      return repo.getCommit("4bd806114ce26503c103c85dcc985021951bbc18");
+    })
+    .then(function(commit) {
+      return commit.getParents(commit.parentcount());
+    })
+    .then(function(parents) {
+      return NodeGit.Merge.base(repo, parents[0], parents[1])
+      .then(function() {
+        return Promise.reject(new Error(
+          "should not be able to retrieve common merge base"));
+      }, function(err) {
+        assert.equal("no merge base found", err.message);
+        assert.equal(NodeGit.Error.CODE.ENOTFOUND, err.errno);
+      });
+    });
+  });
 });