Fix couple nasty bugs in collection.go, safer type assertions.

internal/lib/collection.go

@@ -7,7 +7,6 @@ import (
 // Collection is sync.Map, that stores arbitrary data.
 type Collection struct {
 	items sync.Map
-	close chan struct{}
 }
 
 // Item just interface for stoing any data.
@@ -17,9 +16,7 @@ type item struct {
 
 // NewCollection creates new instance of "collection".
 func NewCollection() *Collection {
-	c := &Collection{ //nolint:exhaustruct
+	c := &Collection{}
-		close: make(chan struct{}),
-	}
 
 	return c
 }
@@ -32,9 +29,12 @@ func (collection *Collection) Get(key any) (any, bool) {
 		return nil, false
 	}
 
-	item := obj.(item)
+	it, ok := obj.(item)
+	if !ok {
+		return nil, false
+	}
 
-	return item.data, true
+	return it.data, true
 }
 
 // Set saves value to given "collection".
@@ -47,9 +47,12 @@ func (collection *Collection) Set(key any, value any) {
 // Range apply function f to all keys/values in collection. Retuns immediatly on first error.
 func (collection *Collection) Range(f func(key, value any) bool) {
 	fn := func(key, value any) bool {
-		item := value.(item)
+		it, ok := value.(item)
+		if !ok {
+			return true
+		}
 
-		return f(key, item.data)
+		return f(key, it.data)
 	}
 
 	collection.items.Range(fn)
@@ -62,7 +65,6 @@ func (collection *Collection) Delete(key any) {
 
 // Close frees memory occupied by collection and deletes collection itself.
 func (collection *Collection) Close() {
-	collection.close <- struct{}{}
 	collection.items = sync.Map{}
 }