grpc: do not use balancer attributes during address comparison

attributes/attributes.go

@@ -112,30 +112,31 @@ func (a *Attributes) String() string {
 	sb.WriteString("{")
 	first := true
 	for k, v := range a.m {
-		var key, val string
-		if str, ok := k.(interface{ String() string }); ok {
-			key = str.String()
-		} else if str, ok := k.(string); ok {
-			key = str
-		}
-		if str, ok := v.(interface{ String() string }); ok {
-			val = str.String()
-		} else if str, ok := v.(string); ok {
-			val = str
-		}
 		if !first {
 			sb.WriteString(", ")
 		}
-		sb.WriteString(fmt.Sprintf("%q: %q ", key, val))
+		sb.WriteString(fmt.Sprintf("%s: %s ", str(k), str(v)))
 		first = false
 	}
 	sb.WriteString("}")
 	return sb.String()
 }
 
+func str(x interface{}) string {
+	if v, ok := x.(fmt.Stringer); ok {
+		return fmt.Sprintf("%q", v.String())
+	} else if v, ok := x.(string); ok {
+		return fmt.Sprintf("%q", v)
+	}
+	return fmt.Sprintf("<%p>", x)
+}
+
 // MarshalJSON helps implement the json.Marshaler interface, thereby rendering
 // the Attributes correctly when printing (via pretty.JSON) structs containing
 // Attributes as fields.
+//
+// Is it impossible to unmarshal attributes from a JSON representation and this
+// method is meant only for debugging purposes.
 func (a *Attributes) MarshalJSON() ([]byte, error) {
 	return []byte(a.String()), nil
 }

internal/stubserver/stubserver.go

@@ -56,9 +56,12 @@ type StubServer struct {
 
 	// Parameters for Listen and Dial. Defaults will be used if these are empty
 	// before Start.
-	Network  string
-	Address  string
-	Target   string
+	Network string
+	Address string
+	Target  string
+
+	// Custom listener to use for serving. If unspecified, a new listener is
+	// created on a local port.
 	Listener net.Listener
 
 	cleanups []func() // Lambdas executed in Stop(); populated by Start().

test/pickfirst_test.go

@@ -351,13 +351,7 @@ func (s) TestPickFirst_StickyTransientFailure(t *testing.T) {
 	}
 	t.Cleanup(func() { cc.Close() })
 
-	// Wait for the channel to move to TransientFailure.
-	for state := cc.GetState(); state != connectivity.TransientFailure; state = cc.GetState() {
-		if !cc.WaitForStateChange(ctx, state) {
-			t.Errorf("Timeout when waiting for state to change to TransientFailure. Current state is %s", state)
-			return
-		}
-	}
+	awaitState(ctx, t, cc, connectivity.TransientFailure)
 
 	// Spawn a goroutine to ensure that the channel stays in TransientFailure.
 	// The call to cc.WaitForStateChange will return false when the main