Add whiteout handling by switching to a two-phase approach. (#139)

* Add whiteout handling by switching to a two-phase approach.

Also only handle hardlinks within one layer

* Simplify the run test.

integration_tests/dockerfiles/Dockerfile_test_mv_add

@@ -0,0 +1,3 @@
+FROM busybox
+ADD context/tars /tmp/tars
+RUN mv /tmp/tars /foo

integration_tests/dockerfiles/Dockerfile_test_run

@@ -14,6 +14,6 @@
 
 FROM gcr.io/google-appengine/debian9
 RUN echo "hey" > /etc/foo
-RUN apt-get update && apt-get install -y \
-  bzr \
-  cvs \
+RUN echo "baz" > /etc/baz
+RUN cp /etc/baz /etc/bar
+RUN rm /etc/baz

integration_tests/dockerfiles/config_test_mv_add.json

@@ -0,0 +1,12 @@
+[
+  {
+    "Image1": "gcr.io/kaniko-test/docker-test-mv-add:latest",
+    "Image2": "gcr.io/kaniko-test/kaniko-test-mv-add:latest",
+    "DiffType": "File",
+    "Diff": {
+      "Adds": null,
+      "Dels": null,
+      "Mods": null
+    }
+  }
+]

integration_tests/dockerfiles/config_test_run.json

@@ -6,43 +6,7 @@
     "Diff": {
       "Adds": null,
       "Dels": null,
-      "Mods": [
-        {
-          "Name": "/var/log/dpkg.log",
-          "Size1": 57481,
-          "Size2": 57481
-        },
-        {
-          "Name": "/var/log/apt/term.log",
-          "Size1": 23671,
-          "Size2": 23671
-        },
-        {
-          "Name": "/var/cache/ldconfig/aux-cache",
-          "Size1": 8057,
-          "Size2": 8057
-        },
-        {
-          "Name": "/var/log/apt/history.log",
-          "Size1": 5661,
-          "Size2": 5661
-        },
-        {
-          "Name": "/var/log/alternatives.log",
-          "Size1": 2579,
-          "Size2": 2579
-        },
-        {
-          "Name": "/usr/lib/python2.7/dist-packages/keyrings/__init__.pyc",
-          "Size1": 140,
-          "Size2": 140
-        },
-        {
-          "Name": "/usr/lib/python2.7/dist-packages/lazr/__init__.pyc",
-          "Size1": 136,
-          "Size2": 136
-        }
-      ]
+      "Mods": null
     }
   }
 ]