Fix race condition with handshaker for connections

GODRIVER-901

Change-Id: I4a41bff911bd6115c0de988f91dab3940f99c07c

Author: skriptble

Makefile

@@ -103,7 +103,7 @@ update-notices:
 
 .PHONY: vet
 vet:
-	go vet -cgocall=false -composites=false -structtags=false -unusedstringmethods="Error" $(PKGS)
+	go vet -cgocall=false -composites=false -unusedstringmethods="Error" $(PKGS)
 
 
 # Evergreen specific targets

mongo/client.go

@@ -230,7 +230,9 @@ func (c *Client) configure(opts *options.ClientOptions) error {
 		))
 	}
 	// Handshaker
-	var handshaker connection.Handshaker = &command.Handshake{Client: command.ClientDoc(appName), Compressors: comps}
+	var handshaker = func(connection.Handshaker) connection.Handshaker {
+		return &command.Handshake{Client: command.ClientDoc(appName), Compressors: comps}
+	}
 	// Auth & Database & Password & Username
 	if opts.Auth != nil {
 		cred := &auth.Cred{
@@ -272,11 +274,11 @@ func (c *Client) configure(opts *options.ClientOptions) error {
 			}
 		}
 
-		handshaker = auth.Handshaker(nil, handshakeOpts)
+		handshaker = func(connection.Handshaker) connection.Handshaker {
+			return auth.Handshaker(nil, handshakeOpts)
+		}
 	}
-	connOpts = append(connOpts, connection.WithHandshaker(
-		func(connection.Handshaker) connection.Handshaker { return handshaker },
-	))
+	connOpts = append(connOpts, connection.WithHandshaker(handshaker))
 	// ConnectTimeout
 	if opts.ConnectTimeout != nil {
 		serverOpts = append(serverOpts, topology.WithHeartbeatTimeout(

mongo/gridfs/bucket.go

@@ -354,7 +354,7 @@ func (b *Bucket) openDownloadStream(filter interface{}, opts ...*options.FindOpt
 	default:
 		fileLen = fileLenElem.Int64()
 	}
-	
+
 	if fileLen == 0 {
 		return newDownloadStream(nil, b.chunkSize, 0), nil
 	}