Refactor runPull to remove second GetImageReferencesAndAuth

Fix unit tests to catch the regression.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

cli/command/image/pull.go

@@ -41,28 +41,25 @@ func NewPullCommand(dockerCli command.Cli) *cobra.Command {
 }
 
 func runPull(cli command.Cli, opts pullOptions) error {
-	ctx := context.Background()
-	imgRefAndAuth, err := trust.GetImageReferencesAndAuth(ctx, AuthResolver(cli), opts.remote)
-	if err != nil {
+	distributionRef, err := reference.ParseNormalizedNamed(opts.remote)
+	switch {
+	case err != nil:
 		return err
-	}
-
-	distributionRef := imgRefAndAuth.Reference()
-	if opts.all && !reference.IsNameOnly(distributionRef) {
+	case opts.all && !reference.IsNameOnly(distributionRef):
 		return errors.New("tag can't be used with --all-tags/-a")
-	}
-
-	if !opts.all && reference.IsNameOnly(distributionRef) {
+	case !opts.all && reference.IsNameOnly(distributionRef):
 		distributionRef = reference.TagNameOnly(distributionRef)
-		imgRefAndAuth, err = trust.GetImageReferencesAndAuth(ctx, AuthResolver(cli), distributionRef.String())
-		if err != nil {
-			return err
-		}
 		if tagged, ok := distributionRef.(reference.Tagged); ok {
 			fmt.Fprintf(cli.Out(), "Using default tag: %s\n", tagged.Tag())
 		}
 	}
 
+	ctx := context.Background()
+	imgRefAndAuth, err := trust.GetImageReferencesAndAuth(ctx, AuthResolver(cli), distributionRef.String())
+	if err != nil {
+		return err
+	}
+
 	// Check if reference has a digest
 	_, isCanonical := distributionRef.(reference.Canonical)
 	if command.IsTrusted() && !isCanonical {

cli/command/image/pull_test.go

@@ -2,11 +2,14 @@ package image
 
 import (
 	"fmt"
+	"io"
 	"io/ioutil"
+	"strings"
 	"testing"
 
 	"github.com/docker/cli/internal/test"
 	"github.com/docker/cli/internal/test/testutil"
+	"github.com/docker/docker/api/types"
 	"github.com/gotestyourself/gotestyourself/golden"
 	"github.com/stretchr/testify/assert"
 )
@@ -44,20 +47,28 @@ func TestNewPullCommandErrors(t *testing.T) {
 
 func TestNewPullCommandSuccess(t *testing.T) {
 	testCases := []struct {
-		name string
-		args []string
+		name        string
+		args        []string
+		expectedTag string
 	}{
 		{
-			name: "simple",
-			args: []string{"image:tag"},
+			name:        "simple",
+			args:        []string{"image:tag"},
+			expectedTag: "image:tag",
 		},
 		{
-			name: "simple-no-tag",
-			args: []string{"image"},
+			name:        "simple-no-tag",
+			args:        []string{"image"},
+			expectedTag: "image:latest",
 		},
 	}
 	for _, tc := range testCases {
-		cli := test.NewFakeCli(&fakeClient{})
+		cli := test.NewFakeCli(&fakeClient{
+			imagePullFunc: func(ref string, options types.ImagePullOptions) (io.ReadCloser, error) {
+				assert.Equal(t, tc.expectedTag, ref, tc.name)
+				return ioutil.NopCloser(strings.NewReader("")), nil
+			},
+		})
 		cmd := NewPullCommand(cli)
 		cmd.SetOutput(ioutil.Discard)
 		cmd.SetArgs(tc.args)