Fixed send-on-closed channel bug in DiscoveryManager (#1472)

Author: cmaglie

arduino/discovery/discoverymanager/discoverymanager.go

@@ -27,28 +27,22 @@ import (
 // DiscoveryManager is required to handle multiple pluggable-discovery that
 // may be shared across platforms
 type DiscoveryManager struct {
-	discoveries   map[string]*discovery.PluggableDiscovery
-	globalEventCh chan *discovery.Event
+	discoveries map[string]*discovery.PluggableDiscovery
 }
 
 var tr = i18n.Tr
 
 // New creates a new DiscoveryManager
 func New() *DiscoveryManager {
 	return &DiscoveryManager{
-		discoveries:   map[string]*discovery.PluggableDiscovery{},
-		globalEventCh: nil,
+		discoveries: map[string]*discovery.PluggableDiscovery{},
 	}
 }
 
 // Clear resets the DiscoveryManager to its initial state
 func (dm *DiscoveryManager) Clear() {
 	dm.QuitAll()
 	dm.discoveries = map[string]*discovery.PluggableDiscovery{}
-	if dm.globalEventCh != nil {
-		close(dm.globalEventCh)
-		dm.globalEventCh = nil
-	}
 }
 
 // IDs returns the list of discoveries' ids in this DiscoveryManager
@@ -134,9 +128,8 @@ func (dm *DiscoveryManager) StartAll() []error {
 // StartSyncAll the discoveries for this DiscoveryManager,
 // returns an error for each discovery failing to start syncing
 func (dm *DiscoveryManager) StartSyncAll() (<-chan *discovery.Event, []error) {
-	if dm.globalEventCh == nil {
-		dm.globalEventCh = make(chan *discovery.Event, 5)
-	}
+	eventSink := make(chan *discovery.Event, 5)
+	var wg sync.WaitGroup
 	errs := dm.parallelize(func(d *discovery.PluggableDiscovery) error {
 		state := d.State()
 		if state != discovery.Idling || state == discovery.Syncing {
@@ -148,14 +141,22 @@ func (dm *DiscoveryManager) StartSyncAll() (<-chan *discovery.Event, []error) {
 		if err != nil {
 			return fmt.Errorf(tr("start syncing discovery %[1]s: %[2]w"), d.GetID(), err)
 		}
+
+		wg.Add(1)
 		go func() {
 			for ev := range eventCh {
-				dm.globalEventCh <- ev
+				eventSink <- ev
 			}
+			wg.Done()
 		}()
 		return nil
 	})
-	return dm.globalEventCh, errs
+	go func() {
+		wg.Wait()
+		eventSink <- &discovery.Event{Type: "quit"}
+		close(eventSink)
+	}()
+	return eventSink, errs
 }
 
 // StopAll the discoveries for this DiscoveryManager,
@@ -189,15 +190,6 @@ func (dm *DiscoveryManager) QuitAll() []error {
 		}
 		return nil
 	})
-	// Close the global channel only if there were no errors
-	// quitting all alive discoveries
-	if len(errs) == 0 && dm.globalEventCh != nil {
-		// Let events consumers that discoveries are quitting no more events
-		// will be sent on this channel
-		dm.globalEventCh <- &discovery.Event{Type: "quit"}
-		close(dm.globalEventCh)
-		dm.globalEventCh = nil
-	}
 	return errs
 }
 

i18n/data/en.po

@@ -2541,7 +2541,7 @@ msgstr "destination dir %s already exists, cannot install"
 msgid "directory doesn't exist: %s"
 msgstr "directory doesn't exist: %s"
 
-#: arduino/discovery/discoverymanager/discoverymanager.go:112
+#: arduino/discovery/discoverymanager/discoverymanager.go:106
 msgid "discovery %[1]s process not started: %[2]w"
 msgstr "discovery %[1]s process not started: %[2]w"
 
@@ -2840,7 +2840,7 @@ msgstr "library not valid"
 msgid "library path does not exist: %s"
 msgstr "library path does not exist: %s"
 
-#: arduino/discovery/discoverymanager/discoverymanager.go:225
+#: arduino/discovery/discoverymanager/discoverymanager.go:217
 msgid "listing ports from discovery %[1]s: %[2]w"
 msgstr "listing ports from discovery %[1]s: %[2]w"
 
@@ -3038,7 +3038,7 @@ msgstr "platform not installed"
 msgid "please use --build-property instead."
 msgstr "please use --build-property instead."
 
-#: arduino/discovery/discoverymanager/discoverymanager.go:67
+#: arduino/discovery/discoverymanager/discoverymanager.go:61
 msgid "pluggable discovery already added: %s"
 msgstr "pluggable discovery already added: %s"
 
@@ -3055,7 +3055,7 @@ msgstr "port not found: %[1]s %[2]s"
 msgid "protocol version not supported: requested 1, got %d"
 msgstr "protocol version not supported: requested 1, got %d"
 
-#: arduino/discovery/discoverymanager/discoverymanager.go:188
+#: arduino/discovery/discoverymanager/discoverymanager.go:189
 msgid "quitting discovery %[1]s: %[2]w"
 msgstr "quitting discovery %[1]s: %[2]w"
 
@@ -3193,19 +3193,19 @@ msgstr "skipping loading of boards %s: malformed custom board options"
 msgid "source is not a directory"
 msgstr "source is not a directory"
 
-#: arduino/discovery/discoverymanager/discoverymanager.go:149
+#: arduino/discovery/discoverymanager/discoverymanager.go:142
 msgid "start syncing discovery %[1]s: %[2]w"
 msgstr "start syncing discovery %[1]s: %[2]w"
 
-#: arduino/discovery/discoverymanager/discoverymanager.go:128
+#: arduino/discovery/discoverymanager/discoverymanager.go:122
 msgid "starting discovery %[1]s: %[2]w"
 msgstr "starting discovery %[1]s: %[2]w"
 
 #: commands/board/list.go:302
 msgid "stopping discoveries: %s"
 msgstr "stopping discoveries: %s"
 
-#: arduino/discovery/discoverymanager/discoverymanager.go:172
+#: arduino/discovery/discoverymanager/discoverymanager.go:173
 msgid "stopping discovery %[1]s: %[2]w"
 msgstr "stopping discovery %[1]s: %[2]w"