fix: valkeycompat NewAdapter sets maxp incorrectly

valkeycompat/adapter.go

@@ -639,8 +639,23 @@ type CacheCompat struct {
 	ttl    time.Duration
 }
 
-func NewAdapter(client valkey.Client) Cmdable {
-	return &Compat{client: client, maxp: runtime.GOMAXPROCS(0)}
+// AdapterOption is a functional option type for NewAdapter
+type AdapterOption func(c *Compat)
+
+// WithNodeScaleoutLimit sets the maximum parallelism for node scaleout operations.
+// If not set, defaults to runtime.GOMAXPROCS(0).
+func WithNodeScaleoutLimit(limit int) AdapterOption {
+	return func(c *Compat) {
+		c.maxp = limit
+	}
+}
+
+func NewAdapter(client valkey.Client, options ...AdapterOption) Cmdable {
+	c := &Compat{client: client, maxp: runtime.GOMAXPROCS(0)}
+	for _, opt := range options {
+		opt(c)
+	}
+	return c
 }
 
 func (c *Compat) Cache(ttl time.Duration) CacheCompat {

valkeycompat/adapter_option_test.go

@@ -0,0 +1,66 @@
+// Copyright (c) 2013 The github.com/go-redis/redis Authors.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package valkeycompat
+
+import (
+	"runtime"
+	"testing"
+
+	"github.com/valkey-io/valkey-go/mock"
+	"go.uber.org/mock/gomock"
+)
+
+func TestWithNodeScaleoutLimit(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+
+	client := mock.NewClient(ctrl)
+
+	t.Run("default maxp is runtime.GOMAXPROCS(0)", func(t *testing.T) {
+		adapter := NewAdapter(client)
+		compat := adapter.(*Compat)
+		if compat.maxp != runtime.GOMAXPROCS(0) {
+			t.Errorf("expected maxp to be %d, got %d", runtime.GOMAXPROCS(0), compat.maxp)
+		}
+	})
+
+	t.Run("WithNodeScaleoutLimit sets maxp", func(t *testing.T) {
+		adapter := NewAdapter(client, WithNodeScaleoutLimit(4))
+		compat := adapter.(*Compat)
+		if compat.maxp != 4 {
+			t.Errorf("expected maxp to be 4, got %d", compat.maxp)
+		}
+	})
+
+	t.Run("multiple options are applied in order", func(t *testing.T) {
+		adapter := NewAdapter(client, WithNodeScaleoutLimit(2), WithNodeScaleoutLimit(8))
+		compat := adapter.(*Compat)
+		if compat.maxp != 8 {
+			t.Errorf("expected maxp to be 8, got %d", compat.maxp)
+		}
+	})
+}