Correctly clean-up pluggable-discoveries on gRPC instance close

Author: cmaglie

commands/internal/instances/instances.go

@@ -172,10 +172,12 @@ func IsValid(inst *rpc.Instance) bool {
 // Delete removes an instance.
 func Delete(inst *rpc.Instance) bool {
 	instancesMux.Lock()
-	defer instancesMux.Unlock()
-	if _, ok := instances[inst.GetId()]; !ok {
+	instance, ok := instances[inst.GetId()]
+	delete(instances, inst.GetId())
+	instancesMux.Unlock()
+	if !ok {
 		return false
 	}
-	delete(instances, inst.GetId())
+	instance.pm.Destroy()
 	return true
 }

internal/arduino/cores/packagemanager/package_manager.go

@@ -197,6 +197,11 @@ func (pm *PackageManager) NewExplorer() (explorer *Explorer, release func()) {
 	}, pm.packagesLock.RUnlock
 }
 
+// Destroy releases all resources held by the PackageManager.
+func (pm *PackageManager) Destroy() {
+	pm.discoveryManager.Clear()
+}
+
 // GetProfile returns the active profile for this package manager, or nil if no profile is selected.
 func (pme *Explorer) GetProfile() *sketch.Profile {
 	return pme.profile