fixed code quality issues using DeepSource

* Added .deepsource.toml

* Removed empty default in select

* Removed unnecessary use of slice

* Fixed check for empty string

Author: withshubh

.deepsource.toml

@@ -0,0 +1,11 @@
+version = 1
+
+test_patterns = ["**/*_test.go"]
+
+[[analyzers]]
+name = "go"
+enabled = true
+
+  [analyzers.meta]
+  import_paths = ["github.com/anacrolix/torrent"]
+  

fs/torrentfs.go

@@ -60,14 +60,14 @@ var (
 )
 
 func isSubPath(parent, child string) bool {
-	if len(parent) == 0 {
+	if parent == "" {
 		return len(child) > 0
 	}
 	if !strings.HasPrefix(child, parent) {
 		return false
 	}
 	extra := child[len(parent):]
-	if len(extra) == 0 {
+	if extra == "" {
 		return false
 	}
 	// Not just a file with more stuff on the end.

mse/mse.go

@@ -133,7 +133,7 @@ func (cr *cipherWriter) Write(b []byte) (n int, err error) {
 			return ret
 		}
 	}()
-	cr.c.XORKeyStream(be[:], b)
+	cr.c.XORKeyStream(be, b)
 	n, err = cr.w.Write(be[:len(b)])
 	if n != len(b) {
 		// The cipher will have advanced beyond the callers stream position.

mse/mse_test.go

@@ -87,7 +87,7 @@ func handshakeTest(t testing.TB, ia []byte, aData, bData string, cryptoProvides
 		go b.Write([]byte(bData))
 		// Need to be exact here, as there are several reads, and net.Pipe is most synchronous.
 		msg := make([]byte, len(ia)+len(aData))
-		n, _ := io.ReadFull(b, msg[:])
+		n, _ := io.ReadFull(b, msg)
 		if n != len(msg) {
 			t.FailNow()
 		}

webtorrent/tracker_client.go

@@ -92,7 +92,7 @@ func (tc *TrackerClient) doWebsocket() error {
 				}
 			case <-closeChan:
 				return
-			default:
+
 			}
 		}
 	}()