Fix cowHostList can't have hosts with same ConnectAddress

cowHostList uses HostInfo.Equal to confirm host uniqueness,
which relies on `ConnectAddress.Equal`, which does not allow to have
different hosts with same `ConnectAddress`

host_source.go

@@ -141,7 +141,7 @@ func (h *HostInfo) Equal(host *HostInfo) bool {
 		return true
 	}
 
-	return h.ConnectAddress().Equal(host.ConnectAddress())
+	return h.HostID() == host.HostID() && h.ConnectAddressAndPort() == host.ConnectAddressAndPort()
 }
 
 func (h *HostInfo) Peer() net.IP {
@@ -402,10 +402,10 @@ func (h *HostInfo) HostnameAndPort() string {
 }
 
 func (h *HostInfo) ConnectAddressAndPort() string {
-        h.mu.Lock()
-        defer h.mu.Unlock()
-        addr, _ := h.connectAddressLocked()
-        return net.JoinHostPort(addr.String(), strconv.Itoa(h.port))
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	addr, _ := h.connectAddressLocked()
+	return net.JoinHostPort(addr.String(), strconv.Itoa(h.port))
 }
 
 func (h *HostInfo) String() string {

policies.go

@@ -12,7 +12,6 @@ import (
 	"fmt"
 	"math"
 	"math/rand"
-	"net"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -64,7 +63,7 @@ func (c *cowHostList) add(host *HostInfo) bool {
 	return true
 }
 
-func (c *cowHostList) remove(ip net.IP) bool {
+func (c *cowHostList) remove(host *HostInfo) bool {
 	c.mu.Lock()
 	l := c.get()
 	size := len(l)
@@ -76,7 +75,7 @@ func (c *cowHostList) remove(ip net.IP) bool {
 	found := false
 	newL := make([]*HostInfo, 0, size)
 	for i := 0; i < len(l); i++ {
-		if !l[i].ConnectAddress().Equal(ip) {
+		if !l[i].Equal(host) {
 			newL = append(newL, l[i])
 		} else {
 			found = true
@@ -333,7 +332,7 @@ func (r *roundRobinHostPolicy) AddHost(host *HostInfo) {
 }
 
 func (r *roundRobinHostPolicy) RemoveHost(host *HostInfo) {
-	r.hosts.remove(host.ConnectAddress())
+	r.hosts.remove(host)
 }
 
 func (r *roundRobinHostPolicy) HostUp(host *HostInfo) {
@@ -499,7 +498,7 @@ func (t *tokenAwareHostPolicy) AddHosts(hosts []*HostInfo) {
 
 func (t *tokenAwareHostPolicy) RemoveHost(host *HostInfo) {
 	t.mu.Lock()
-	if t.hosts.remove(host.ConnectAddress()) {
+	if t.hosts.remove(host) {
 		meta := t.getMetadataForUpdate()
 		meta.resetTokenRing(t.partitioner, t.hosts.get(), t.logger)
 		t.updateReplicas(meta, t.getKeyspaceName())
@@ -843,9 +842,9 @@ func (d *dcAwareRR) AddHost(host *HostInfo) {
 
 func (d *dcAwareRR) RemoveHost(host *HostInfo) {
 	if d.IsLocal(host) {
-		d.localHosts.remove(host.ConnectAddress())
+		d.localHosts.remove(host)
 	} else {
-		d.remoteHosts.remove(host.ConnectAddress())
+		d.remoteHosts.remove(host)
 	}
 }
 
@@ -950,7 +949,7 @@ func (d *rackAwareRR) AddHost(host *HostInfo) {
 
 func (d *rackAwareRR) RemoveHost(host *HostInfo) {
 	dist := d.HostTier(host)
-	d.hosts[dist].remove(host.ConnectAddress())
+	d.hosts[dist].remove(host)
 }
 
 func (d *rackAwareRR) HostUp(host *HostInfo)   { d.AddHost(host) }

policies_test.go

@@ -43,6 +43,32 @@ func TestRoundRobbin(t *testing.T) {
 	}
 }
 
+func TestRoundRobbinSameConnectAddress(t *testing.T) {
+	policy := RoundRobinHostPolicy()
+
+	hosts := [...]*HostInfo{
+		{hostId: "0", connectAddress: net.IPv4(0, 0, 0, 1), port: 9042},
+		{hostId: "1", connectAddress: net.IPv4(0, 0, 0, 1), port: 9043},
+	}
+
+	for _, host := range hosts {
+		policy.AddHost(host)
+	}
+
+	got := make(map[string]bool)
+	it := policy.Pick(nil)
+	for h := it(); h != nil; h = it() {
+		id := h.Info().hostId
+		if got[id] {
+			t.Fatalf("got duplicate host: %v", id)
+		}
+		got[id] = true
+	}
+	if len(got) != len(hosts) {
+		t.Fatalf("expected %d hosts got %d", len(hosts), len(got))
+	}
+}
+
 // Tests of the token-aware host selection policy implementation with a
 // round-robin host selection policy fallback.
 func TestHostPolicy_TokenAware_SimpleStrategy(t *testing.T) {