Convert git.VerifyRef into a more versatile ShowRefs

mislav · mislav · commit c36b84e550dc · 2020-03-26T19:21:40.000+01:00
This is so we can pass a list of full qualified refs and have them
resolved for both existence and their commit hashes.
diff --git a/command/pr_checkout.go b/command/pr_checkout.go
@@ -66,7 +66,7 @@ func prCheckout(cmd *cobra.Command, args []string) error {
 		cmdQueue = append(cmdQueue, []string{"git", "fetch", headRemote.Name, refSpec})
 
 		// local branch already exists
-		if git.VerifyRef("refs/heads/" + newBranchName) {
+		if _, err := git.ShowRefs("refs/heads/" + newBranchName); err == nil {
 			cmdQueue = append(cmdQueue, []string{"git", "checkout", newBranchName})
 			cmdQueue = append(cmdQueue, []string{"git", "merge", "--ff-only", fmt.Sprintf("refs/remotes/%s", remoteBranch)})
 		} else {
diff --git a/command/pr_checkout_test.go b/command/pr_checkout_test.go
@@ -46,7 +46,7 @@ func TestPRCheckout_sameRepo(t *testing.T) {
 	ranCommands := [][]string{}
 	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
 		switch strings.Join(cmd.Args, " ") {
-		case "git show-ref --verify --quiet refs/heads/feature":
+		case "git show-ref --verify -- refs/heads/feature":
 			return &errorStub{"exit status: 1"}
 		default:
 			ranCommands = append(ranCommands, cmd.Args)
@@ -98,7 +98,7 @@ func TestPRCheckout_urlArg(t *testing.T) {
 	ranCommands := [][]string{}
 	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
 		switch strings.Join(cmd.Args, " ") {
-		case "git show-ref --verify --quiet refs/heads/feature":
+		case "git show-ref --verify -- refs/heads/feature":
 			return &errorStub{"exit status: 1"}
 		default:
 			ranCommands = append(ranCommands, cmd.Args)
@@ -147,7 +147,7 @@ func TestPRCheckout_urlArg_differentBase(t *testing.T) {
 	ranCommands := [][]string{}
 	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
 		switch strings.Join(cmd.Args, " ") {
-		case "git show-ref --verify --quiet refs/heads/feature":
+		case "git show-ref --verify -- refs/heads/feature":
 			return &errorStub{"exit status: 1"}
 		default:
 			ranCommands = append(ranCommands, cmd.Args)
@@ -210,7 +210,7 @@ func TestPRCheckout_branchArg(t *testing.T) {
 	ranCommands := [][]string{}
 	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
 		switch strings.Join(cmd.Args, " ") {
-		case "git show-ref --verify --quiet refs/heads/feature":
+		case "git show-ref --verify -- refs/heads/feature":
 			return &errorStub{"exit status: 1"}
 		default:
 			ranCommands = append(ranCommands, cmd.Args)
@@ -260,7 +260,7 @@ func TestPRCheckout_existingBranch(t *testing.T) {
 	ranCommands := [][]string{}
 	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
 		switch strings.Join(cmd.Args, " ") {
-		case "git show-ref --verify --quiet refs/heads/feature":
+		case "git show-ref --verify -- refs/heads/feature":
 			return &test.OutputStub{}
 		default:
 			ranCommands = append(ranCommands, cmd.Args)
@@ -313,7 +313,7 @@ func TestPRCheckout_differentRepo_remoteExists(t *testing.T) {
 	ranCommands := [][]string{}
 	restoreCmd := utils.SetPrepareCmd(func(cmd *exec.Cmd) utils.Runnable {
 		switch strings.Join(cmd.Args, " ") {
-		case "git show-ref --verify --quiet refs/heads/feature":
+		case "git show-ref --verify -- refs/heads/feature":
 			return &errorStub{"exit status: 1"}
 		default:
 			ranCommands = append(ranCommands, cmd.Args)
diff --git a/git/git.go b/git/git.go
@@ -13,10 +13,31 @@ import (
 	"github.com/cli/cli/utils"
 )
 
-func VerifyRef(ref string) bool {
-	showRef := exec.Command("git", "show-ref", "--verify", "--quiet", ref)
-	err := utils.PrepareCmd(showRef).Run()
-	return err == nil
+// Ref represents a git commit reference
+type Ref struct {
+	Hash string
+	Name string
+}
+
+// ShowRefs resolves fully-qualified refs to commit hashes
+func ShowRefs(ref ...string) ([]Ref, error) {
+	args := append([]string{"show-ref", "--verify", "--"}, ref...)
+	showRef := exec.Command("git", args...)
+	output, err := utils.PrepareCmd(showRef).Output()
+
+	var refs []Ref
+	for _, line := range outputLines(output) {
+		parts := strings.SplitN(line, " ", 2)
+		if len(parts) < 2 {
+			continue
+		}
+		refs = append(refs, Ref{
+			Hash: parts[0],
+			Name: parts[1],
+		})
+	}
+
+	return refs, err
 }
 
 // CurrentBranch reads the checked-out branch for the git repository
