common/interrupt: close connections outside group lock

common/interrupt/group_test.go

@@ -0,0 +1,66 @@
+package interrupt
+
+import (
+	"net"
+	"sync"
+	"testing"
+	"time"
+)
+
+type closeBarrierConn struct {
+	net.Conn
+	barrier *sync.WaitGroup
+}
+
+func (c *closeBarrierConn) Close() error {
+	c.barrier.Done()
+	c.barrier.Wait()
+	return c.Conn.Close()
+}
+
+func TestNestedGroupsInterruptWithoutDeadlock(t *testing.T) {
+	groupA := NewGroup()
+	groupB := NewGroup()
+	barrier := &sync.WaitGroup{}
+	barrier.Add(2)
+
+	barrierA, barrierAPeer := net.Pipe()
+	barrierB, barrierBPeer := net.Pipe()
+	t.Cleanup(func() {
+		barrierAPeer.Close()
+		barrierBPeer.Close()
+	})
+	groupA.NewConn(&closeBarrierConn{Conn: barrierA, barrier: barrier}, true, false)
+	groupB.NewConn(&closeBarrierConn{Conn: barrierB, barrier: barrier}, true, false)
+
+	connA, connAPeer := net.Pipe()
+	connB, connBPeer := net.Pipe()
+	t.Cleanup(func() {
+		connAPeer.Close()
+		connBPeer.Close()
+	})
+	wrapperA := groupA.NewConn(connA, true, false)
+	wrapperB := groupB.NewConn(connB, true, false)
+	groupA.NewConn(wrapperB, true, false)
+	groupB.NewConn(wrapperA, true, false)
+
+	done := make(chan struct{}, 2)
+	go func() {
+		groupA.Interrupt(true)
+		done <- struct{}{}
+	}()
+	go func() {
+		groupB.Interrupt(true)
+		done <- struct{}{}
+	}()
+
+	timeout := time.NewTimer(time.Second)
+	defer timeout.Stop()
+	for range 2 {
+		select {
+		case <-done:
+		case <-timeout.C:
+			t.Fatal("nested group interrupt deadlocked")
+		}
+	}
+}