CFG_VER/APP_VER in the env file: invalid configs replaced, updates follow APP_VER (dev/stable/pin)

internal/service/service_linux.go

@@ -15,8 +15,6 @@ import (
 	"os/signal"
 	"path/filepath"
 	"syscall"
-
-	"gpu-turnstile/internal/config"
 )
 
 // Name matches the Windows service name; the systemd unit is Name + ".service".
@@ -172,26 +170,16 @@ func Install(configPath string, copyBin bool, version string) error {
 			}
 		}
 		exe = installedExe
-		data, readErr := os.ReadFile(etcConfig)
-		switch {
-		case os.IsNotExist(readErr):
-			if configPath != "" {
-				copyFile(configPath, etcConfig, 0o644) //nolint:errcheck // best effort
-			} else if err := os.WriteFile(etcConfig, []byte(config.SampleEnv(version, "")), 0o644); err != nil {
-				// Fully commented sample covering every setting; LOG_FILE
-				// stays commented — stderr goes to the journal on Linux.
-				return fmt.Errorf("write %s: %w", etcConfig, err)
-			}
-		case readErr != nil:
-			return fmt.Errorf("read %s: %w", etcConfig, readErr)
-		default:
-			// An installer-written config from an older version gets any
-			// new settings appended; hand-written files stay untouched.
-			if synced, changed := config.SyncSample(string(data), version, ""); changed {
-				if err := os.WriteFile(etcConfig, []byte(synced), 0o644); err != nil {
-					return fmt.Errorf("write %s: %w", etcConfig, err)
-				}
-			}
+		if _, err := os.Stat(etcConfig); os.IsNotExist(err) && configPath != "" {
+			copyFile(configPath, etcConfig, 0o644) //nolint:errcheck // best effort
+		}
+		// Missing configs get a fully commented sample (LOG_FILE stays
+		// commented — stderr goes to the journal on Linux);
+		// installer-written ones from older versions get new settings
+		// appended; anything without CFG_VER is invalid and gets replaced
+		// (backup kept as .bak).
+		if err := syncEnvFile(etcConfig, version, ""); err != nil {
+			return err
 		}
 	} else if configPath != "" {
 		if abs, absErr := filepath.Abs(configPath); absErr == nil {