preallocated simple errors

Author: htemelski-oss

osscluster.go

@@ -3,6 +3,7 @@ package redis
 import (
 	"context"
 	"crypto/tls"
+	"errors"
 	"fmt"
 	"math"
 	"net"
@@ -29,7 +30,11 @@ const (
 	minLatencyMeasurementInterval = 10 * time.Second
 )
 
-var errClusterNoNodes = fmt.Errorf("redis: cluster has no nodes")
+var (
+	errClusterNoNodes = errors.New("redis: cluster has no nodes")
+	errNoWatchKeys    = errors.New("redis: Watch requires at least one key")
+	errWatchCrosslot  = errors.New("redis: Watch requires all keys to be in the same slot")
+)
 
 // ClusterOptions are used to configure a cluster client and should be
 // passed to NewClusterClient.
@@ -1838,14 +1843,13 @@ func (c *ClusterClient) cmdsMoved(
 
 func (c *ClusterClient) Watch(ctx context.Context, fn func(*Tx) error, keys ...string) error {
 	if len(keys) == 0 {
-		return fmt.Errorf("redis: Watch requires at least one key")
+		return errNoWatchKeys
 	}
 
 	slot := hashtag.Slot(keys[0])
 	for _, key := range keys[1:] {
 		if hashtag.Slot(key) != slot {
-			err := fmt.Errorf("redis: Watch requires all keys to be in the same slot")
-			return err
+			return errWatchCrosslot
 		}
 	}
 

osscluster_router.go

@@ -2,6 +2,7 @@ package redis
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"reflect"
 	"strings"
@@ -12,6 +13,14 @@ import (
 	"github.com/redis/go-redis/v9/internal/routing"
 )
 
+var (
+	errInvalidCmdPointer         = errors.New("redis: invalid command pointer")
+	errNoCmdsToAggregate         = errors.New("redis: no commands to aggregate")
+	errNoResToAggregate          = errors.New("redis: no results to aggregate")
+	errInvalidCursorCmdArgsCount = errors.New("redis: FT.CURSOR command requires at least 3 arguments")
+	errInvalidCursorIdType       = errors.New("redis: invalid cursor ID type")
+)
+
 // slotResult represents the result of executing a command on a specific slot
 type slotResult struct {
 	cmd  Cmder
@@ -275,12 +284,12 @@ func (c *ClusterClient) executeSpecialCommand(ctx context.Context, cmd Cmder, po
 func (c *ClusterClient) executeCursorCommand(ctx context.Context, cmd Cmder) error {
 	args := cmd.Args()
 	if len(args) < 4 {
-		return fmt.Errorf("redis: FT.CURSOR command requires at least 3 arguments")
+		return errInvalidCursorCmdArgsCount
 	}
 
 	cursorID, ok := args[3].(string)
 	if !ok {
-		return fmt.Errorf("redis: invalid cursor ID type")
+		return errInvalidCursorIdType
 	}
 
 	// Route based on cursor ID to maintain stickiness
@@ -394,7 +403,7 @@ func (c *ClusterClient) aggregateMultiSlotResults(ctx context.Context, cmd Cmder
 // aggregateKeyedValues aggregates individual key-value pairs while preserving key order
 func (c *ClusterClient) aggregateKeyedValues(cmd Cmder, keyedResults map[string]routing.AggregatorResErr, keyOrder []string, policy *routing.CommandPolicy) error {
 	if len(keyedResults) == 0 {
-		return fmt.Errorf("redis: no results to aggregate")
+		return errNoResToAggregate
 	}
 
 	aggregator := c.createAggregator(policy, cmd, true)
@@ -419,7 +428,7 @@ func (c *ClusterClient) aggregateKeyedValues(cmd Cmder, keyedResults map[string]
 // aggregateResponses aggregates multiple shard responses
 func (c *ClusterClient) aggregateResponses(cmd Cmder, cmds []Cmder, policy *routing.CommandPolicy) error {
 	if len(cmds) == 0 {
-		return fmt.Errorf("redis: no commands to aggregate")
+		return errNoCmdsToAggregate
 	}
 
 	if len(cmds) == 1 {
@@ -958,7 +967,7 @@ func (c *ClusterClient) setCommandValue(cmd Cmder, value interface{}) error {
 func (c *ClusterClient) setCommandValueReflection(cmd Cmder, value interface{}) error {
 	cmdValue := reflect.ValueOf(cmd)
 	if cmdValue.Kind() != reflect.Ptr || cmdValue.IsNil() {
-		return fmt.Errorf("redis: invalid command pointer")
+		return errInvalidCmdPointer
 	}
 
 	setValMethod := cmdValue.MethodByName("SetVal")