Fixed potential panic in error handler when Redis is down. (#31643)

changes/30455-errorstore-panic

@@ -0,0 +1 @@
+Fixed potential panic in error handler when Redis is down.

server/errorstore/errors.go

@@ -12,6 +12,7 @@ import (
 	"crypto/sha256"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"strconv"
@@ -208,6 +209,14 @@ func (h *Handler) storeError(ctx context.Context, err error) {
 		return
 	}
 
+	// Check if pool is nil to prevent panic
+	if h.pool == nil {
+		if h.testOnStore != nil {
+			h.testOnStore(errors.New("redis pool is nil"))
+		}
+		return
+	}
+
 	// not using a connection that follows redirections here
 	// in order to do pipeline commands
 	conn := h.pool.Get()