local snapshot save always has .zip extension

Author: anisaoshafi

internal/snapshot/destination.go

@@ -10,15 +10,16 @@ import (
 
 // ParseDestination resolves the user-supplied path to an absolute local path,
 // or returns an error for cloud/bare names. When dest is empty, a default name
-// based on now (UTC) is used, e.g. "snapshot-2026-05-11T21-04-32".
+// based on now (UTC) is used, e.g. "snapshot-2026-05-11T21-04-32.zip".
+// The returned path always has a .zip extension.
 func ParseDestination(dest string, now time.Time) (string, error) {
 	if dest == "" {
 		dest = "./" + now.UTC().Format("snapshot-2006-01-02T15-04-05")
 	} else if strings.Contains(dest, "://") {
-		return "", fmt.Errorf("cloud destinations are not yet supported — use a file path like ./my-snapshot")
+		return "", fmt.Errorf("cloud destinations are not yet supported — use a file path like ./my-snapshot.zip")
 	} else if !strings.HasPrefix(dest, ".") && !strings.HasPrefix(dest, "~") && !filepath.IsAbs(dest) && filepath.Base(dest) == dest {
 		// bare name with no path separators: reserved for future cloud pod names
-		return "", fmt.Errorf("cloud destinations are not yet supported — use a file path like ./my-snapshot")
+		return "", fmt.Errorf("cloud destinations are not yet supported — use a file path like ./my-snapshot.zip")
 	}
 	if dest == "~" || strings.HasPrefix(dest, "~/") || strings.HasPrefix(dest, `~\`) {
 		home, err := os.UserHomeDir()
@@ -31,5 +32,8 @@ func ParseDestination(dest string, now time.Time) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("resolve path: %w", err)
 	}
+	if !strings.EqualFold(filepath.Ext(abs), ".zip") {
+		abs += ".zip"
+	}
 	return abs, nil
 }

internal/snapshot/destination_test.go

@@ -20,7 +20,7 @@ func TestParseDestinationDefault(t *testing.T) {
 	now := time.Date(2026, 5, 11, 21, 4, 32, 0, time.UTC)
 	got, err := snapshot.ParseDestination("", now)
 	require.NoError(t, err)
-	assert.Equal(t, filepath.Join(wd, "snapshot-2026-05-11T21-04-32"), got)
+	assert.Equal(t, filepath.Join(wd, "snapshot-2026-05-11T21-04-32.zip"), got)
 }
 
 func TestParseDestination(t *testing.T) {
@@ -41,23 +41,31 @@ func TestParseDestination(t *testing.T) {
 	tests := []testCase{
 		{
 			input:    "./my-state",
-			wantPath: filepath.Join(wd, "my-state"),
+			wantPath: filepath.Join(wd, "my-state.zip"),
 		},
 		{
 			input:    filepath.Join(os.TempDir(), "state"),
-			wantPath: filepath.Join(os.TempDir(), "state"),
+			wantPath: filepath.Join(os.TempDir(), "state.zip"),
 		},
 		{
 			input:    "~",
-			wantPath: home,
+			wantPath: home + ".zip",
 		},
 		{
 			input:    "~/snapshots/s",
-			wantPath: filepath.Join(home, "snapshots", "s"),
+			wantPath: filepath.Join(home, "snapshots", "s.zip"),
 		},
 		{
 			input:    "subdir/state",
-			wantPath: filepath.Join(wd, "subdir", "state"),
+			wantPath: filepath.Join(wd, "subdir", "state.zip"),
+		},
+		{
+			input:    "./checkpoint.zip",
+			wantPath: filepath.Join(wd, "checkpoint.zip"),
+		},
+		{
+			input:    "./already.ZIP",
+			wantPath: filepath.Join(wd, "already.ZIP"),
 		},
 		{
 			input:   "my-pod",
@@ -75,9 +83,9 @@ func TestParseDestination(t *testing.T) {
 
 	if runtime.GOOS == "windows" {
 		tests = append(tests,
-			testCase{input: `~\snapshots\s`, wantPath: filepath.Join(home, "snapshots", "s")},
-			testCase{input: `C:\Users\user\snap`, wantPath: `C:\Users\user\snap`},
-			testCase{input: `C:/Users/user/snap`, wantPath: `C:\Users\user\snap`},
+			testCase{input: `~\snapshots\s`, wantPath: filepath.Join(home, "snapshots", "s.zip")},
+			testCase{input: `C:\Users\user\snap`, wantPath: `C:\Users\user\snap.zip`},
+			testCase{input: `C:/Users/user/snap`, wantPath: `C:\Users\user\snap.zip`},
 		)
 	}
 
@@ -88,7 +96,7 @@ func TestParseDestination(t *testing.T) {
 			if tc.wantErr != "" {
 				require.Error(t, err)
 				assert.Contains(t, err.Error(), tc.wantErr)
-				assert.Contains(t, err.Error(), "./my-snapshot")
+				assert.Contains(t, err.Error(), "./my-snapshot.zip")
 				return
 			}
 			require.NoError(t, err)