[Chore] Fix lint warnings from #47247 (#47648)

Author: belimawr

filebeat/input/filestream/input.go

@@ -717,6 +717,7 @@ func (inp *filestream) readFromSource(
 		//nolint:gosec // message.Bytes is always positive
 		metrics.BytesProcessed.Add(uint64(message.Bytes))
 		if isGZIP {
+			//nolint:gosec // message.Bytes is always positive, no risk of overflow here
 			metrics.BytesGZIPProcessed.Add(uint64(message.Bytes))
 		}
 
@@ -725,8 +726,10 @@ func (inp *filestream) readFromSource(
 			_ = mapstr.AddTags(message.Fields, []string{"take_over"})
 		}
 
-		if isGZIP && message.Private == io.EOF {
-			s.EOF = true
+		if isGZIP {
+			if err, ok := (message.Private).(error); ok && errors.Is(err, io.EOF) {
+				s.EOF = true
+			}
 		}
 		if err := p.Publish(message.ToEvent(), s); err != nil {
 			metrics.ProcessingErrors.Inc()

filebeat/input/filestream/internal/input-logfile/input.go

@@ -33,7 +33,6 @@ type managedInput struct {
 	// id is the input ID, it is defined by setting 'id'
 	// in the input configuration
 	id               string
-	metricsID        string
 	manager          *InputManager
 	ackCH            *updateChan
 	sourceIdentifier *SourceIdentifier
@@ -104,10 +103,10 @@ func (inp *managedInput) Run(
 }
 
 func newInputACKHandler(ch *updateChan) beat.EventListener {
-	return acker.EventPrivateReporter(func(acked int, private []interface{}) {
+	return acker.EventPrivateReporter(func(acked int, private []any) {
 		var n uint
 		var last int
-		for i := 0; i < len(private); i++ {
+		for i := range private {
 			current := private[i]
 			if current == nil {
 				continue
@@ -125,6 +124,7 @@ func newInputACKHandler(ch *updateChan) beat.EventListener {
 			return
 		}
 
+		//nolint:errcheck // We know it is alwys the correct type
 		op := private[last].(*updateOp)
 		ch.Send(scheduledUpdate{op: op, n: n})
 	})

filebeat/input/filestream/internal/input-logfile/store.go

@@ -285,7 +285,7 @@ func (s *sourceStore) UpdateIdentifiers(getNewID func(v Value) (string, any)) {
 			//  - 3. Finally, synchronously remove it from the disk store.
 			s.store.UpdateTTL(res, 0)
 			delete(s.store.ephemeralStore.table, res.key)
-			s.store.persistentStore.Remove(res.key)
+			_ = s.store.persistentStore.Remove(res.key)
 			s.store.log.Infof("migrated entry in registry from '%s' to '%s'. Cursor: %v", key, newKey, r.cursor)
 		}
 
@@ -341,7 +341,7 @@ func (s *sourceStore) TakeOver(fn func(Value) (string, any)) {
 	// a Filestream input
 	fromLogInput := map[string]logInputState{}
 	if len(s.identifiersToTakeOver) == 0 {
-		s.store.persistentStore.Each(func(key string, value statestore.ValueDecoder) (bool, error) {
+		_ = s.store.persistentStore.Each(func(key string, value statestore.ValueDecoder) (bool, error) {
 			if strings.HasPrefix(key, "filebeat::logs::") {
 				m := mapstr.M{}
 				if err := value.Decode(&m); err != nil {
@@ -450,7 +450,7 @@ func (s *sourceStore) TakeOver(fn func(Value) (string, any)) {
 			//  - 3. Finally, synchronously remove it from the disk store.
 			s.store.UpdateTTL(res, 0)
 			delete(s.store.ephemeralStore.table, res.key)
-			s.store.persistentStore.Remove(res.key)
+			_ = s.store.persistentStore.Remove(res.key)
 			s.store.log.Infof("migrated entry in registry from '%s' to '%s'. Cursor: %v", k, newKey, r.cursor)
 		}
 
@@ -484,7 +484,7 @@ func (s *sourceStore) TakeOver(fn func(Value) (string, any)) {
 		// it read when Filebeat was starting, thus "overriding" this delete.
 		// We keep it here because when we remove the Log input we will ensure
 		// the entry is actually remove from the disk store.
-		s.store.persistentStore.Remove(k)
+		_ = s.store.persistentStore.Remove(k)
 		res.Release()
 		s.store.log.Infof("migrated entry in registry from '%s' to '%s'. Cursor: %v", k, newKey, res.cursor)
 	}
@@ -507,7 +507,7 @@ func logInputStateFromMapM(m mapstr.M) (logInputState, error) {
 
 	// typeconf.Convert kept failing with an "unsupported" error because
 	// FileStateOS was present, we don't need it, so just delete it.
-	m.Delete("FileStateOS") //nolint:errcheck // The key is always there
+	m.Delete("FileStateOS")
 	if err := typeconv.Convert(&state, m); err != nil {
 		return logInputState{}, fmt.Errorf("cannot convert Log input state: %w", err)
 	}

filebeat/input/filestream/prospector_creator_test.go

@@ -49,7 +49,7 @@ func TestCreateProspector(t *testing.T) {
 					IgnoreInactive: ignoreInactiveSettings[test.ignore_inactive_since],
 				}
 				p, _ := newProspector(c, logp.NewNopLogger(), mustSourceIdentifier("foo-id"))
-				fileProspector := p.(*fileProspector)
+				fileProspector := p.(*fileProspector) //nolint:errcheck // we know the type
 				assert.Equal(t, fileProspector.ignoreInactiveSince, ignoreInactiveSettings[test.ignore_inactive_since])
 			})
 		}

filebeat/input/filestream/prospector_test.go

@@ -107,7 +107,7 @@ func TestProspector_InitUpdateIdentifiers(t *testing.T) {
 	}
 	defer f.Close()
 	tmpFileName := f.Name()
-	fi, err := f.Stat() //nolint:typecheck // It is used on L151
+	fi, err := f.Stat()
 	if err != nil {
 		t.Fatalf("cannot stat test file: %v", err)
 	}