Fix: setting the container name to the image

In commit 47ac961 the image name that is used
for setting the container name is taken from the resolved image
unless it is empty.

The image has the "Names" field and right now the first name is
taken. However, when the image is a tagged image, the container name
will end up using the original name instead of the given one.

For example:

$ buildah tag busybox busybox1
$ buildah from busybox1

Will set the name of the container as "busybox-working-container"
while it was expected to be "busybox1-working-container".

This patch fixes this particular issue.

Signed-off-by: Boaz Shuster <ripcurld.github@gmail.com>

Closes: #399
Approved by: rhatdan

new.go

@@ -77,6 +77,24 @@ func pullAndFindImage(store storage.Store, imageName string, options BuilderOpti
 	return img, ref, nil
 }
 
+func getImageName(name string, img *storage.Image) string {
+	imageName := name
+	if len(img.Names) > 0 {
+		imageName = img.Names[0]
+		// When the image used by the container is a tagged image
+		// the container name might be set to the original image instead of
+		// the image given in the "form" command line.
+		// This loop is supposed to fix this.
+		for _, n := range img.Names {
+			if strings.Contains(n, name) {
+				imageName = n
+				break
+			}
+		}
+	}
+	return imageName
+}
+
 func imageNamePrefix(imageName string) string {
 	prefix := imageName
 	s := strings.Split(imageName, "/")
@@ -207,9 +225,7 @@ func newBuilder(store storage.Store, options BuilderOptions) (*Builder, error) {
 	image := options.FromImage
 	imageID := ""
 	if img != nil {
-		if len(img.Names) > 0 {
-			image = img.Names[0]
-		}
+		image = getImageName(image, img)
 		imageID = img.ID
 	}
 	if manifest, config, err = imageManifestAndConfig(ref, systemContext); err != nil {

new_test.go

@@ -0,0 +1,28 @@
+package buildah
+
+import (
+	"testing"
+
+	"github.com/containers/storage"
+)
+
+func TestGetImageName(t *testing.T) {
+	tt := []struct {
+		caseName string
+		name     string
+		names    []string
+		expected string
+	}{
+		{"tagged image", "busybox1", []string{"docker.io/library/busybox:latest", "docker.io/library/busybox1:latest"}, "docker.io/library/busybox1:latest"},
+		{"image name not in the resolved image names", "image1", []string{"docker.io/library/busybox:latest", "docker.io/library/busybox1:latest"}, "docker.io/library/busybox:latest"},
+		{"resolved image with empty name list", "image1", []string{}, "image1"},
+	}
+
+	for _, tc := range tt {
+		img := &storage.Image{Names: tc.names}
+		res := getImageName(tc.name, img)
+		if res != tc.expected {
+			t.Errorf("test case '%s' failed: expected %#v but got %#v", tc.caseName, tc.expected, res)
+		}
+	}
+}

tests/from.bats

@@ -73,7 +73,6 @@ load helpers
 }
 
 @test "from-authenticate-cert-and-creds" {
-
   mkdir -p  ${TESTDIR}/auth
   # Create creds and store in ${TESTDIR}/auth/htpasswd
 #  docker run --entrypoint htpasswd registry:2 -Bbn testuser testpassword > ${TESTDIR}/auth/htpasswd
@@ -112,3 +111,14 @@ load helpers
 #  buildah rm $ctrid
 #  buildah rmi -f $(buildah --debug=false images -q)
 }
+
+@test "from-tagged-image" {
+  # Github #396: Make sure the container name starts with the correct image even when it's tagged.
+  cid=$(buildah from --pull=false --signature-policy ${TESTSDIR}/policy.json scratch)
+  buildah commit --signature-policy ${TESTSDIR}/policy.json "$cid" scratch2
+  buildah rm $cid
+  buildah tag scratch2 scratch3
+  cid=$(buildah from --signature-policy ${TESTSDIR}/policy.json scratch3)
+  [ "$cid" == scratch3-working-container ]
+  buildah rmi -f --all
+}