Distinguish missing playlist file from invalid format

A missing or unreadable path now fails with "Could not open playlist file:
no such file" instead of the format-validation message, which was misleading
for a mistyped path. Extracted openPlaylist as the shared resolve-check-sniff
entry point for the print and build commands.

Author: statik

cmd/plt.go

@@ -16,6 +16,7 @@ package cmd
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -49,12 +50,7 @@ offline; no media is downloaded.`,
 }
 
 func runPltPrint(_ *coral.Command, args []string) {
-	path := resolveInputPath(args[0])
-
-	arc, err := sniffPlaylist(path)
-	if err != nil {
-		log.Fatal().Err(err).Msgf("Not a valid purple playlist: %s", path)
-	}
+	arc := openPlaylist(args[0])
 	defer func() { _ = arc.Close() }()
 
 	if arc.schemaVersion != verifiedSchemaVersion {
@@ -93,6 +89,35 @@ func resolveInputPath(p string) string {
 	return p
 }
 
+// checkPlaylistFile reports a clear, path-focused error when the file is
+// missing or unreadable, keeping it distinct from a format-validation failure.
+func checkPlaylistFile(path string) error {
+	if _, err := os.Stat(path); err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return fmt.Errorf("no such file: %s", path)
+		}
+		return fmt.Errorf("could not access %s: %w", path, err)
+	}
+	return nil
+}
+
+// openPlaylist resolves the argument, fails fast with a distinct message when
+// the file is missing, then sniffs and returns the validated archive. Shared
+// by the print and build commands.
+func openPlaylist(rawPath string) *archive {
+	path := resolveInputPath(rawPath)
+
+	if err := checkPlaylistFile(path); err != nil {
+		log.Fatal().Err(err).Msg("Could not open playlist file")
+	}
+
+	arc, err := sniffPlaylist(path)
+	if err != nil {
+		log.Fatal().Err(err).Msgf("Not a valid purple playlist: %s", path)
+	}
+	return arc
+}
+
 // printView is the offline summary rendered by plt print, shared by the text
 // and JSON outputs so both show the same data.
 type printView struct {

cmd/plt_print_test.go

@@ -17,6 +17,7 @@ package cmd
 import (
 	"encoding/json"
 	"math"
+	"os"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -49,6 +50,27 @@ func TestResolveInputPath(t *testing.T) {
 	})
 }
 
+func TestCheckPlaylistFile(t *testing.T) {
+	dir := t.TempDir()
+
+	present := filepath.Join(dir, "present.playlist")
+	if err := os.WriteFile(present, []byte("data"), 0o600); err != nil {
+		t.Fatalf("write fixture: %v", err)
+	}
+	if err := checkPlaylistFile(present); err != nil {
+		t.Errorf("existing file should pass, got: %v", err)
+	}
+
+	missing := filepath.Join(dir, "missing.playlist")
+	err := checkPlaylistFile(missing)
+	if err == nil {
+		t.Fatal("missing file should error")
+	}
+	if !strings.Contains(err.Error(), "no such file") {
+		t.Errorf("error %q should mention 'no such file'", err.Error())
+	}
+}
+
 func TestDescribeSource(t *testing.T) {
 	cases := []struct {
 		name string