From fa56a8fcad4ef6c2d582c4e49654902b3ba899e9 Mon Sep 17 00:00:00 2001
From: Matthew Herrmann <mherr@google.com>
Date: Thu, 31 Oct 2019 20:01:14 -0700
Subject: [PATCH 1/3] -a

Fix connection leak caused by rapid context cancellation (https://github.com/go-sql-driver/mysql/issues/1023)
---
 connector.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/connector.go b/connector.go
index 5aaaba43e..bbad4e23b 100644
--- a/connector.go
+++ b/connector.go
@@ -64,6 +64,7 @@ func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
 	// Call startWatcher for context support (From Go 1.8)
 	mc.startWatcher()
 	if err := mc.watchCancel(ctx); err != nil {
+		mc.cleanup()
 		return nil, err
 	}
 	defer mc.finish()

From 65d32e4375a2970804833978b31f8e0198917349 Mon Sep 17 00:00:00 2001
From: Matthew Herrmann <mherr@google.com>
Date: Thu, 31 Oct 2019 20:37:42 -0700
Subject: [PATCH 2/3] -a

Regression test for https://github.com/go-sql-driver/mysql/issues/1023.
---
 driver_go110_test.go | 52 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/driver_go110_test.go b/driver_go110_test.go
index 19a0e5956..d83e31ab9 100644
--- a/driver_go110_test.go
+++ b/driver_go110_test.go
@@ -135,3 +135,55 @@ func TestConnectorTimeoutsDuringOpen(t *testing.T) {
 		t.Fatalf("(*Connector).Connect should have timed out")
 	}
 }
+
+// A connection which can only be closed.
+type dummyConnection struct {
+	net.Conn
+	closed bool
+}
+
+func (d *dummyConnection) Close() error {
+	d.closed = true
+	return nil
+}
+
+func TestConnectorTimeoutsWatchCancel(t *testing.T) {
+	var (
+		cancel  func()           // Used to cancel the context just after connecting.
+		created *dummyConnection // The created connection.
+	)
+
+	RegisterDialContext("TestConnectorTimeoutsWatchCancel", func(ctx context.Context, addr string) (net.Conn, error) {
+		// Canceling at this time triggers the watchCancel error branch in Connect().
+		cancel()
+		created = &dummyConnection{}
+		return created, nil
+	})
+
+	mycnf := NewConfig()
+	mycnf.User = "root"
+	mycnf.Addr = "foo"
+	mycnf.Net = "TestConnectorTimeoutsWatchCancel"
+
+	conn, err := NewConnector(mycnf)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	db := sql.OpenDB(conn)
+	defer db.Close()
+
+	var ctx context.Context
+	ctx, cancel = context.WithCancel(context.Background())
+
+	if _, err := db.Conn(ctx); err != context.Canceled {
+		t.Errorf("got %v, want context.Canceled", err)
+	}
+
+	if created == nil {
+		t.Fatal("no connection created")
+	}
+	if !created.closed {
+		t.Errorf("connection not closed")
+	}
+}

From 12b2ae1513db26f1f7414b6c50b53568d42f63ab Mon Sep 17 00:00:00 2001
From: Matthew Herrmann <mherr@google.com>
Date: Thu, 31 Oct 2019 20:54:17 -0700
Subject: [PATCH 3/3] -a

fix go vet warning for possibly-unused cancel (https://github.com/go-sql-driver/mysql/issues/1023)
---
 driver_go110_test.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/driver_go110_test.go b/driver_go110_test.go
index d83e31ab9..fd8df8975 100644
--- a/driver_go110_test.go
+++ b/driver_go110_test.go
@@ -175,6 +175,7 @@ func TestConnectorTimeoutsWatchCancel(t *testing.T) {
 
 	var ctx context.Context
 	ctx, cancel = context.WithCancel(context.Background())
+	defer cancel()
 
 	if _, err := db.Conn(ctx); err != context.Canceled {
 		t.Errorf("got %v, want context.Canceled", err)