clean commit branches more thoroughly

branches.go

@@ -144,19 +144,29 @@ func switchToCommitBranch(rc requestContext) (string, error) {
 		}
 	}
 
-	// Clean existing output paths
-	for appName, appConfig := range rc.target.branchConfig.AppConfigs {
-		var outputDir string
-		if appConfig.OutputPath != "" {
-			outputDir = filepath.Join(rc.repo.WorkingDir(), appConfig.OutputPath)
-		} else {
-			outputDir = filepath.Join(rc.repo.WorkingDir(), appName)
-		}
-		if err := os.RemoveAll(outputDir); err != nil {
-			return "", errors.Wrapf(err, "error deleting %q", outputDir)
-		}
+	// Clean the branch so we can replace its contents wholesale
+	if err := cleanCommitBranch(rc.repo.WorkingDir()); err != nil {
+		return "", errors.Wrap(err, "error cleaning commit branch")
 	}
 	logger.Debug("cleaned commit branch")
 
 	return commitBranch, nil
 }
+
+// cleanCommitBranch deletes the entire contents of the specified directory
+// EXCEPT for the .git and .kargo-render subdirectories.
+func cleanCommitBranch(dir string) error {
+	dirEntries, err := os.ReadDir(dir)
+	if err != nil {
+		return err
+	}
+	for _, dirEntry := range dirEntries {
+		if dirEntry.Name() == ".git" || dirEntry.Name() == ".kargo-render" {
+			continue
+		}
+		if err = os.RemoveAll(filepath.Join(dir, dirEntry.Name())); err != nil {
+			return err
+		}
+	}
+	return nil
+}

branches_test.go

@@ -1,6 +1,7 @@
 package render
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
@@ -93,3 +94,65 @@ func TestWriteBranchMetadata(t *testing.T) {
 	require.NoError(t, err)
 	require.True(t, exists)
 }
+
+func TestCleanCommitBranch(t *testing.T) {
+	const subdirCount = 50
+	const fileCount = 50
+	// Create dummy repo dir
+	dir, err := createDummyCommitBranchDir(subdirCount, fileCount)
+	defer os.RemoveAll(dir)
+	require.NoError(t, err)
+	// Double-check the setup
+	dirEntries, err := os.ReadDir(dir)
+	require.NoError(t, err)
+	require.Len(t, dirEntries, subdirCount+fileCount+2)
+	// Delete
+	err = cleanCommitBranch(dir)
+	require.NoError(t, err)
+	// .git should not have been deleted
+	_, err = os.Stat(filepath.Join(dir, ".git"))
+	require.NoError(t, err)
+	// .kargo-render should not have been deleted
+	_, err = os.Stat(filepath.Join(dir, ".kargo-render"))
+	require.NoError(t, err)
+	// Everything else should be deleted
+	dirEntries, err = os.ReadDir(dir)
+	require.NoError(t, err)
+	require.Len(t, dirEntries, 2)
+}
+
+func createDummyCommitBranchDir(dirCount, fileCount int) (string, error) {
+	// Create a directory
+	dir, err := os.MkdirTemp("", "")
+	if err != nil {
+		return dir, err
+	}
+	// Add a dummy .git/ subdir
+	if err = os.Mkdir(filepath.Join(dir, ".git"), 0755); err != nil {
+		return dir, err
+	}
+	// Add a dummy .kargo-render/ subdir
+	if err = os.Mkdir(filepath.Join(dir, ".kargo-render"), 0755); err != nil {
+		return dir, err
+	}
+	// Add some other dummy dirs
+	for i := 0; i < dirCount; i++ {
+		if err = os.Mkdir(
+			filepath.Join(dir, fmt.Sprintf("dir-%d", i)),
+			0755,
+		); err != nil {
+			return dir, err
+		}
+	}
+	// Add some dummy files
+	for i := 0; i < fileCount; i++ {
+		file, err := os.Create(filepath.Join(dir, fmt.Sprintf("file-%d", i)))
+		if err != nil {
+			return dir, err
+		}
+		if err = file.Close(); err != nil {
+			return dir, err
+		}
+	}
+	return dir, nil
+}