chore(model): the easier linter complaints

lib/model/model.go

@@ -195,7 +195,7 @@ var (
 	ErrFolderMissing    = errors.New("no such folder")
 	errNoVersioner      = errors.New("folder has no versioner")
 	// errors about why a connection is closed
-	errStopped                            = errors.New("Syncthing is being stopped")
+	errStopped                            = errors.New("Syncthing is being stopped") //nolint:staticcheck
 	errEncryptionInvConfigLocal           = errors.New("can't encrypt outgoing data because local data is encrypted (folder-type receive-encrypted)")
 	errEncryptionInvConfigRemote          = errors.New("remote has encrypted data and encrypts that data for us - this is impossible")
 	errEncryptionNotEncryptedLocal        = errors.New("remote expects to exchange encrypted data, but is configured for plain data")
@@ -622,24 +622,26 @@ func (m *model) UsageReportingStats(report *contract.Report, version int, previe
 
 			for _, line := range lines {
 				// Allow prefixes to be specified in any order, but only once.
+			loop:
 				for {
-					if strings.HasPrefix(line, "!") && !seenPrefix[0] {
+					switch {
+					case strings.HasPrefix(line, "!") && !seenPrefix[0]:
 						seenPrefix[0] = true
 						line = line[1:]
 						report.IgnoreStats.Inverts++
-					} else if strings.HasPrefix(line, "(?i)") && !seenPrefix[1] {
+					case strings.HasPrefix(line, "(?i)") && !seenPrefix[1]:
 						seenPrefix[1] = true
 						line = line[4:]
 						report.IgnoreStats.Folded++
-					} else if strings.HasPrefix(line, "(?d)") && !seenPrefix[2] {
+					case strings.HasPrefix(line, "(?d)") && !seenPrefix[2]:
 						seenPrefix[2] = true
 						line = line[4:]
 						report.IgnoreStats.Deletable++
-					} else {
+					default:
 						seenPrefix[0] = false
 						seenPrefix[1] = false
 						seenPrefix[2] = false
-						break
+						break loop
 					}
 				}
 
@@ -1227,9 +1229,10 @@ func (m *model) ClusterConfig(conn protocol.Connection, cm *protocol.ClusterConf
 	for _, folder := range cm.Folders {
 		info := &clusterConfigDeviceInfo{}
 		for _, dev := range folder.Devices {
-			if dev.ID == m.id {
+			switch dev.ID {
+			case m.id:
 				info.local = dev
-			} else if dev.ID == deviceID {
+			case deviceID:
 				info.remote = dev
 			}
 			if info.local.ID != protocol.EmptyDeviceID && info.remote.ID != protocol.EmptyDeviceID {
@@ -1451,7 +1454,7 @@ func (m *model) ccHandleFolders(folders []protocol.Folder, deviceCfg config.Devi
 			sameError := false
 			m.mut.Lock()
 			if devs, ok := m.folderEncryptionFailures[folder.ID]; ok {
-				sameError = devs[deviceID] == err
+				sameError = devs[deviceID] == err //nolint:errorlint
 			} else {
 				m.folderEncryptionFailures[folder.ID] = make(map[protocol.DeviceID]error)
 			}
@@ -1461,7 +1464,8 @@ func (m *model) ccHandleFolders(folders []protocol.Folder, deviceCfg config.Devi
 			if sameError {
 				l.Debugln(msg)
 			} else {
-				if rerr, ok := err.(*redactedError); ok {
+				var rerr *redactedError
+				if errors.As(err, &rerr) {
 					err = rerr.redacted
 				}
 				m.evLogger.Log(events.Failure, err.Error())
@@ -2015,7 +2019,7 @@ func (m *model) Request(conn protocol.Connection, req *protocol.Request) (out pr
 
 	// The requestResponse releases the bytes to the buffer pool and the
 	// limiters when its Close method is called.
-	res := newLimitedRequestResponse(int(req.Size), limiter, m.globalRequestLimiter)
+	res := newLimitedRequestResponse(req.Size, limiter, m.globalRequestLimiter)
 
 	defer func() {
 		// Close it ourselves if it isn't returned due to an error
@@ -2061,16 +2065,17 @@ func (m *model) Request(conn protocol.Connection, req *protocol.Request) (out pr
 	}
 
 	n, err := readOffsetIntoBuf(folderFs, req.Name, req.Offset, res.data)
-	if fs.IsNotExist(err) {
+	switch {
+	case fs.IsNotExist(err):
 		l.Debugf("%v REQ(in) file doesn't exist: %s: %q / %q o=%d s=%d", m, deviceID.Short(), req.Folder, req.Name, req.Offset, req.Size)
 		return nil, protocol.ErrNoSuchFile
-	} else if err == io.EOF {
+	case errors.Is(err, io.EOF):
 		// Read beyond end of file. This might indicate a problem, or it
 		// might be a short block that gets padded when read for encrypted
 		// folders. We ignore the error and let the hash validation in the
 		// next step take care of it, by only hashing the part we actually
 		// managed to read.
-	} else if err != nil {
+	case err != nil:
 		l.Debugf("%v REQ(in) failed reading file (%v): %s: %q / %q o=%d s=%d", m, err, deviceID.Short(), req.Folder, req.Name, req.Offset, req.Size)
 		return nil, protocol.ErrGeneric
 	}
@@ -2230,13 +2235,13 @@ func (m *model) SetIgnores(folder string, content []string) error {
 
 func (m *model) setIgnores(cfg config.FolderConfiguration, content []string) error {
 	err := cfg.CheckPath()
-	if err == config.ErrPathMissing {
+	if errors.Is(err, config.ErrPathMissing) {
 		if err = cfg.CreateRoot(); err != nil {
 			return fmt.Errorf("failed to create folder root: %w", err)
 		}
 		err = cfg.CheckPath()
 	}
-	if err != nil && err != config.ErrMarkerMissing {
+	if err != nil && !errors.Is(err, config.ErrMarkerMissing) {
 		return err
 	}
 
@@ -2498,7 +2503,6 @@ func (m *model) ScanFolders() map[string]error {
 	wg := sync.NewWaitGroup()
 	wg.Add(len(folders))
 	for _, folder := range folders {
-		folder := folder
 		go func() {
 			err := m.ScanFolder(folder)
 			if err != nil {
@@ -2677,7 +2681,7 @@ func (m *model) WatchError(folder string) error {
 	runner, _ := m.folderRunners.Get(folder)
 	m.mut.RUnlock()
 	if err != nil {
-		return nil // If the folder isn't running, there's no error to report.
+		return nil //nolint:nilerr // If the folder isn't running, there's no error to report.
 	}
 	return runner.WatchError()
 }
@@ -2744,7 +2748,7 @@ func (m *model) GlobalDirectoryTree(folder, prefix string, levels int, dirsOnly
 	prefix = osutil.NativeFilename(prefix)
 
 	if prefix != "" && !strings.HasSuffix(prefix, sep) {
-		prefix = prefix + sep
+		prefix += sep
 	}
 
 	for f, err := range itererr.Zip(m.sdb.AllGlobalFilesPrefix(folder, prefix)) {
@@ -3456,8 +3460,8 @@ type updatedPendingFolder struct {
 // redactPathError checks if the error is actually a os.PathError, and if yes
 // returns a redactedError with the path removed.
 func redactPathError(err error) (error, bool) {
-	perr, ok := err.(*os.PathError)
-	if !ok {
+	var perr *os.PathError
+	if !errors.As(err, &perr) {
 		return nil, false
 	}
 	return &redactedError{