Support cloning into existing and empty directory

2 files changed, 54 insertions, 14 deletions

diff --git a/client/go/internal/cli/cmd/clone.go b/client/go/internal/cli/cmd/clone.go
index 6fb97581ea3..a835892990b 100644
--- a/client/go/internal/cli/cmd/clone.go
+++ b/client/go/internal/cli/cmd/clone.go
@@ -6,8 +6,10 @@ package cmd
 
 import (
 	"archive/zip"
+	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"log"
 	"net/http"
 	"os"
@@ -76,6 +78,23 @@ type zipFile struct {
 	modTime time.Time
 }
 
+func (c *cloner) createDirectory(path string) error {
+	if err := os.Mkdir(path, 0755); err != nil {
+		if errors.Is(err, fs.ErrExist) {
+			entries, err := os.ReadDir(path)
+			if err != nil {
+				return err
+			}
+			if len(entries) > 0 {
+				return fmt.Errorf("%s already exists and is not empty", path)
+			}
+		} else {
+			return err
+		}
+	}
+	return nil
+}
+
 // Clone copies the application identified by applicationName into given path. If the cached copy of sample applications
 // has expired (as determined by its entity tag), a current copy will be downloaded from GitHub automatically.
 func (c *cloner) Clone(applicationName, path string) error {
@@ -95,9 +114,8 @@ func (c *cloner) Clone(applicationName, path string) error {
 		dirPrefix := "sample-apps-master/" + applicationName + "/"
 		if strings.HasPrefix(f.Name, dirPrefix) {
 			if !found { // Create destination directory lazily when source is found
-				createErr := os.Mkdir(path, 0755)
-				if createErr != nil {
-					return fmt.Errorf("could not create directory '%s': %w", color.CyanString(path), createErr)
+				if err := c.createDirectory(path); err != nil {
+					return fmt.Errorf("could not create directory: %w", err)
 				}
 			}
 			found = true
@@ -111,7 +129,7 @@ func (c *cloner) Clone(applicationName, path string) error {
 	if !found {
 		return errHint(fmt.Errorf("could not find source application '%s'", color.CyanString(applicationName)), "Use -f to ignore the cache")
 	} else {
-		log.Print("Created ", color.CyanString(path))
+		log.Print("Cloned into ", color.CyanString(path))
 	}
 	return nil
 }
diff --git a/client/go/internal/cli/cmd/clone_test.go b/client/go/internal/cli/cmd/clone_test.go
index f136299db85..3d7250cc760 100644
--- a/client/go/internal/cli/cmd/clone_test.go
+++ b/client/go/internal/cli/cmd/clone_test.go
@@ -18,14 +18,16 @@ import (
 )
 
 func TestClone(t *testing.T) {
-	assertCreated("text-search", "mytestapp", t)
-}
-
-func assertCreated(sampleAppName string, app string, t *testing.T) {
+	origWd, err := os.Getwd()
+	require.Nil(t, err)
+	sampleAppName := "text-search"
+	app := "mytestapp"
 	tempDir := t.TempDir()
 	app1 := filepath.Join(tempDir, "app1")
-	defer os.RemoveAll(app)
-
+	t.Cleanup(func() {
+		os.Chdir(origWd)
+		os.RemoveAll(app)
+	})
 	httpClient := &mock.HTTPClient{}
 	cli, stdout, stderr := newTestCLI(t)
 	cli.httpClient = httpClient
@@ -35,7 +37,7 @@ func assertCreated(sampleAppName string, app string, t *testing.T) {
 	// Initial cloning. GitHub includes the ETag header, but we don't require it
 	httpClient.NextResponseBytes(200, testdata)
 	require.Nil(t, cli.Run("clone", sampleAppName, app1))
-	assert.Equal(t, "Created "+app1+"\n", stdout.String())
+	assert.Equal(t, "Cloned into "+app1+"\n", stdout.String())
 	assertFiles(t, app1)
 
 	// Clone with cache hit
@@ -43,8 +45,27 @@ func assertCreated(sampleAppName string, app string, t *testing.T) {
 	stdout.Reset()
 	app2 := filepath.Join(tempDir, "app2")
 	require.Nil(t, cli.Run("clone", sampleAppName, app2))
-	assert.Equal(t, "Using cached sample apps ...\nCreated "+app2+"\n", stdout.String())
+	assert.Equal(t, "Using cached sample apps ...\nCloned into "+app2+"\n", stdout.String())
 	assertFiles(t, app2)
+	stdout.Reset()
+
+	// Clone to current directory (dot)
+	emptyDir := filepath.Join(tempDir, "mypath1")
+	require.Nil(t, os.Mkdir(emptyDir, 0755))
+	require.Nil(t, os.Chdir(emptyDir))
+	httpClient.NextStatus(http.StatusNotModified)
+	require.Nil(t, cli.Run("clone", sampleAppName, "."))
+	assert.Equal(t, "Using cached sample apps ...\nCloned into .\n", stdout.String())
+	assertFiles(t, ".")
+	stdout.Reset()
+
+	// Clone to non-empty directory
+	httpClient.NextStatus(http.StatusNotModified)
+	nonEmptyDir := filepath.Join(tempDir, "mypath2")
+	require.Nil(t, os.MkdirAll(filepath.Join(nonEmptyDir, "more"), 0755))
+	require.NotNil(t, cli.Run("clone", sampleAppName, nonEmptyDir))
+	assert.Equal(t, "Error: could not create directory: "+nonEmptyDir+" already exists and is not empty\n", stderr.String())
+	stderr.Reset()
 
 	// Clone while ignoring cache
 	headers := make(http.Header)
@@ -53,7 +74,7 @@ func assertCreated(sampleAppName string, app string, t *testing.T) {
 	stdout.Reset()
 	app3 := filepath.Join(tempDir, "app3")
 	require.Nil(t, cli.Run("clone", "-f", sampleAppName, app3))
-	assert.Equal(t, "Created "+app3+"\n", stdout.String())
+	assert.Equal(t, "Cloned into "+app3+"\n", stdout.String())
 	assertFiles(t, app3)
 
 	// Cloning falls back to cached copy if GitHub is unavailable
@@ -62,7 +83,7 @@ func assertCreated(sampleAppName string, app string, t *testing.T) {
 	app4 := filepath.Join(tempDir, "app4")
 	require.Nil(t, cli.Run("clone", "-f=false", sampleAppName, app4))
 	assert.Equal(t, "Warning: could not download sample apps: github returned status 500\n", stderr.String())
-	assert.Equal(t, "Using cached sample apps ...\nCreated "+app4+"\n", stdout.String())
+	assert.Equal(t, "Using cached sample apps ...\nCloned into "+app4+"\n", stdout.String())
 	assertFiles(t, app4)
 
 	// The only cached file is the latest one
@@ -79,6 +100,7 @@ func assertCreated(sampleAppName string, app string, t *testing.T) {
 }
 
 func assertFiles(t *testing.T, app string) {
+	t.Helper()
 	assert.True(t, util.PathExists(filepath.Join(app, "README.md")))
 	assert.True(t, util.PathExists(filepath.Join(app, "src", "main", "application")))
 	assert.True(t, util.IsDirectory(filepath.Join(app, "src", "main", "application")))