Add robust error handling for TCP communication

Windows side:
- sendManifest/sendEvent now return errors
- Callers log errors and reconnect on failure

Linux side:
- 30s read timeout to detect dead connections
- Better batch counting and logging
- Proper error logging on disconnect

1 files changed, 33 insertions, 12 deletions

diff --git a/cmd_windows.go b/cmd_windows.go
index dfe137a..621cf3b 100644
--- a/cmd_windows.go
+++ b/cmd_windows.go
@@ -86,7 +86,11 @@ func run() {
 
 		logInfo("watcher: connected, sending manifest ...")
 
-		sendManifest(conn, manifest)
+		if err := sendManifest(conn, manifest); err != nil {
+			logErrorf("send manifest: %v", err)
+			conn.Close()
+			continue
+		}
 
 		logInfo("watcher: monitoring for changes ...")
 
@@ -210,7 +214,9 @@ func watchLoop(ctx context.Context, conn net.Conn, watcher *fsnotify.Watcher, ma
 					delete(manifest.Files, path)
 				}
 
-				sendEvent(conn, evt)
+				if err := sendEvent(conn, evt); err != nil {
+					logErrorf("send event: %v", err)
+				}
 			})
 			mu.Unlock()
 
@@ -274,7 +280,7 @@ func scanDirectory(root string, stack *GitignoreStack) *Manifest {
 	return manifest
 }
 
-func sendManifest(conn net.Conn, manifest *Manifest) {
+func sendManifest(conn net.Conn, manifest *Manifest) error {
 	const batchSize = 1000
 	files := make([]FileMetaJSON, 0, batchSize)
 	paths := make([]string, 0, batchSize)
@@ -291,9 +297,14 @@ func sendManifest(conn net.Conn, manifest *Manifest) {
 			for i, p := range paths {
 				msg.Files[p] = files[i]
 			}
-			data, _ := EncodeMessage(msg)
+			data, err := EncodeMessage(msg)
+			if err != nil {
+				return err
+			}
 			data = append(data, '\n')
-			conn.Write(data)
+			if _, err := conn.Write(data); err != nil {
+				return err
+			}
 			files = files[:0]
 			paths = paths[:0]
 		}
@@ -307,18 +318,27 @@ func sendManifest(conn net.Conn, manifest *Manifest) {
 		for i, p := range paths {
 			msg.Files[p] = files[i]
 		}
-		data, _ := EncodeMessage(msg)
+		data, err := EncodeMessage(msg)
+		if err != nil {
+			return err
+		}
 		data = append(data, '\n')
-		conn.Write(data)
+		if _, err := conn.Write(data); err != nil {
+			return err
+		}
 	}
 
 	done := &ProtocolMessage{Type: "manifest_done"}
-	doneData, _ := EncodeMessage(done)
+	doneData, err := EncodeMessage(done)
+	if err != nil {
+		return err
+	}
 	doneData = append(doneData, '\n')
-	conn.Write(doneData)
+	_, err = conn.Write(doneData)
+	return err
 }
 
-func sendEvent(conn net.Conn, evt FileEvent) {
+func sendEvent(conn net.Conn, evt FileEvent) error {
 	msg := &ProtocolMessage{Path: evt.Path}
 	switch evt.Op {
 	case "create":
@@ -330,10 +350,11 @@ func sendEvent(conn net.Conn, evt FileEvent) {
 	}
 	data, err := EncodeMessage(msg)
 	if err != nil {
-		return
+		return err
 	}
 	data = append(data, '\n')
-	conn.Write(data)
+	_, err = conn.Write(data)
+	return err
 }
 
 func addWatchersRecursively(watcher *fsnotify.Watcher, root string, stack *GitignoreStack) error {