fix leaking statesync test (#6680)

internal/statesync/dispatcher.go

@@ -57,7 +57,7 @@ func (d *dispatcher) LightBlock(ctx context.Context, height int64) (*types.Light
 
 	// fetch the next peer id in the list and request a light block from that
 	// peer
-	peer := d.availablePeers.Pop()
+	peer := d.availablePeers.Pop(ctx)
 	lb, err := d.lightBlock(ctx, height, peer)
 	return lb, peer, err
 }
@@ -272,7 +272,7 @@ func (l *peerlist) Len() int {
 	return len(l.peers)
 }
 
-func (l *peerlist) Pop() types.NodeID {
+func (l *peerlist) Pop(ctx context.Context) types.NodeID {
 	l.mtx.Lock()
 	if len(l.peers) == 0 {
 		// if we don't have any peers in the list we block until a peer is
@@ -281,8 +281,13 @@ func (l *peerlist) Pop() types.NodeID {
 		l.waiting = append(l.waiting, wait)
 		// unlock whilst waiting so that the list can be appended to
 		l.mtx.Unlock()
-		peer := <-wait
-		return peer
+		select {
+		case peer := <-wait:
+			return peer
+
+		case <-ctx.Done():
+			return ""
+		}
 	}
 
 	peer := l.peers[0]

internal/statesync/dispatcher_test.go

@@ -95,7 +95,7 @@ func TestPeerListBasic(t *testing.T) {
 
 	half := numPeers / 2
 	for i := 0; i < half; i++ {
-		assert.Equal(t, peerSet[i], peerList.Pop())
+		assert.Equal(t, peerSet[i], peerList.Pop(ctx))
 	}
 	assert.Equal(t, half, peerList.Len())
 
@@ -104,7 +104,7 @@ func TestPeerListBasic(t *testing.T) {
 
 	peerList.Remove(peerSet[half])
 	half++
-	assert.Equal(t, peerSet[half], peerList.Pop())
+	assert.Equal(t, peerSet[half], peerList.Pop(ctx))
 
 }
 
@@ -117,7 +117,7 @@ func TestPeerListConcurrent(t *testing.T) {
 	// peer list hasn't been populated each these go routines should block
 	for i := 0; i < numPeers/2; i++ {
 		go func() {
-			_ = peerList.Pop()
+			_ = peerList.Pop(ctx)
 			wg.Done()
 		}()
 	}
@@ -132,7 +132,7 @@ func TestPeerListConcurrent(t *testing.T) {
 	// we request the second half of the peer set
 	for i := 0; i < numPeers/2; i++ {
 		go func() {
-			_ = peerList.Pop()
+			_ = peerList.Pop(ctx)
 			wg.Done()
 		}()
 	}