Merge pull request #24 from arduino/scerza/gracefully-close

Handle closing of uevent reader gracefully

Author: silvanocerza

go.mod

@@ -5,7 +5,7 @@ require (
 	github.com/arduino/go-properties-orderedmap v1.6.0
 	github.com/arduino/pluggable-discovery-protocol-handler/v2 v2.0.1
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/s-urbaniak/uevent v1.0.0
+	github.com/s-urbaniak/uevent v1.0.1
 	go.bug.st/serial v1.3.1
 	golang.org/x/sys v0.0.0-20210806184541-e5e7981a1069
 )

go.sum

@@ -15,8 +15,8 @@ github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/s-urbaniak/uevent v1.0.0 h1:y1e40TmDfCU0l1o/MBpimGJgo2UzTTqBl/0GF6vx/io=
-github.com/s-urbaniak/uevent v1.0.0/go.mod h1:h83SVc1NQj/EubPaK4hWyiG217xLYr+fS+Jf10COrG0=
+github.com/s-urbaniak/uevent v1.0.1 h1:Zy6g16gR1m6iRB+scDtyExP9KRYnuSdTWOYhBE5O620=
+github.com/s-urbaniak/uevent v1.0.1/go.mod h1:h83SVc1NQj/EubPaK4hWyiG217xLYr+fS+Jf10COrG0=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=

sync/sync_linux.go

@@ -19,6 +19,7 @@ package sync
 
 import (
 	"fmt"
+	"io"
 
 	discovery "github.com/arduino/pluggable-discovery-protocol-handler/v2"
 	"github.com/s-urbaniak/uevent"
@@ -49,12 +50,6 @@ func Start(eventCB discovery.EventCallback, errorCB discovery.ErrorCallback) (ch
 
 	// Run synchronous event emitter
 	go func() {
-		defer func() {
-			recover()
-			// This recovers from "bufio: reader returned negative count from Read" panic
-			// when the underlying stream is closed
-		}()
-
 		// Output initial port state
 		for _, port := range current {
 			eventCB("add", toDiscoveryPort(port))
@@ -63,7 +58,11 @@ func Start(eventCB discovery.EventCallback, errorCB discovery.ErrorCallback) (ch
 		dec := uevent.NewDecoder(syncReader)
 		for {
 			evt, err := dec.Decode()
-			if err != nil {
+			if err == io.EOF {
+				// The underlying syncReader has been closed
+				// so there's nothing else to read
+				return
+			} else if err != nil {
 				errorCB(fmt.Sprintf("Error decoding serial event: %s", err))
 				return
 			}