Correct parent chain in v2 push when v1Compatibility files on the disk are inconsistent

This fixes an issue where two images with the same filesystem contents
and configuration but different remote IDs could share a v1Compatibility
file, resulting in corrupted manifests.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Upstream-commit: 0ab6b1d9221f7a2a65c6565fed8f3d6f29fcec2d
Component: engine

components/engine/integration-cli/docker_cli_push_test.go

@@ -2,13 +2,16 @@ package main
 
 import (
 	"archive/tar"
+	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"strings"
 	"time"
 
+	"github.com/docker/docker/image"
 	"github.com/docker/docker/pkg/integration/checker"
 	"github.com/go-check/check"
 )
@@ -83,6 +86,46 @@ func (s *DockerRegistrySuite) TestPushMultipleTags(c *check.C) {
 	}
 }
 
+// TestPushBadParentChain tries to push an image with a corrupted parent chain
+// in the v1compatibility files, and makes sure the push process fixes it.
+func (s *DockerRegistrySuite) TestPushBadParentChain(c *check.C) {
+	repoName := fmt.Sprintf("%v/dockercli/badparent", privateRegistryURL)
+
+	id, err := buildImage(repoName, `
+	    FROM busybox
+	    CMD echo "adding another layer"
+	    `, true)
+	if err != nil {
+		c.Fatal(err)
+	}
+
+	// Push to create v1compatibility file
+	dockerCmd(c, "push", repoName)
+
+	// Corrupt the parent in the v1compatibility file from the top layer
+	filename := filepath.Join(dockerBasePath, "graph", id, "v1Compatibility")
+
+	jsonBytes, err := ioutil.ReadFile(filename)
+	c.Assert(err, check.IsNil, check.Commentf("Could not read v1Compatibility file: %s", err))
+
+	var img image.Image
+	err = json.Unmarshal(jsonBytes, &img)
+	c.Assert(err, check.IsNil, check.Commentf("Could not unmarshal json: %s", err))
+
+	img.Parent = "1234123412341234123412341234123412341234123412341234123412341234"
+
+	jsonBytes, err = json.Marshal(&img)
+	c.Assert(err, check.IsNil, check.Commentf("Could not marshal json: %s", err))
+
+	err = ioutil.WriteFile(filename, jsonBytes, 0600)
+	c.Assert(err, check.IsNil, check.Commentf("Could not write v1Compatibility file: %s", err))
+
+	dockerCmd(c, "push", repoName)
+
+	// pull should succeed
+	dockerCmd(c, "pull", repoName)
+}
+
 func (s *DockerRegistrySuite) TestPushEmptyLayer(c *check.C) {
 	repoName := fmt.Sprintf("%v/dockercli/emptylayer", privateRegistryURL)
 	emptyTarball, err := ioutil.TempFile("", "empty_tarball")