GODRIVER-3037 Support internal-only options.

internal/cmd/compilecheck/main.go

@@ -12,9 +12,13 @@ import (
 	"go.mongodb.org/mongo-driver/v2/bson"
 	"go.mongodb.org/mongo-driver/v2/mongo"
 	"go.mongodb.org/mongo-driver/v2/mongo/options"
+	"go.mongodb.org/mongo-driver/v2/x/mongo/driver/xoptions"
 )
 
 func main() {
+	opts := options.Client()
+	xoptions.SetInternalClientOptions(opts, "foo", "bar")
+
 	_, _ = mongo.Connect(options.Client())
 	fmt.Println(bson.D{{Key: "key", Value: "value"}})
 }

internal/options/options.go

@@ -0,0 +1,45 @@
+// Copyright (C) MongoDB, Inc. 2025-present.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package options
+
+// Options stores internal options.
+type Options struct {
+	values map[string]any
+}
+
+// WithValue sets an option value with the associated key.
+func WithValue(opts Options, key string, option any) Options {
+	if opts.values == nil {
+		opts.values = make(map[string]any)
+	}
+	opts.values[key] = option
+	return opts
+}
+
+// Value returns the value associated with the options for key.
+func Value(opts Options, key string) any {
+	if opts.values == nil {
+		return nil
+	}
+	if val, ok := opts.values[key]; ok {
+		return val
+	}
+	return nil
+}
+
+// Equal compares two Options instances for equality.
+func Equal(opts1, opts2 Options) bool {
+	if len(opts1.values) != len(opts2.values) {
+		return false
+	}
+	for key, val1 := range opts1.values {
+		if val2, ok := opts2.values[key]; !ok || val1 != val2 {
+			return false
+		}
+	}
+	return true
+}

mongo/options/clientoptions.go

@@ -26,6 +26,7 @@ import (
 	"go.mongodb.org/mongo-driver/v2/bson"
 	"go.mongodb.org/mongo-driver/v2/event"
 	"go.mongodb.org/mongo-driver/v2/internal/httputil"
+	"go.mongodb.org/mongo-driver/v2/internal/options"
 	"go.mongodb.org/mongo-driver/v2/mongo/readconcern"
 	"go.mongodb.org/mongo-driver/v2/mongo/readpref"
 	"go.mongodb.org/mongo-driver/v2/mongo/writeconcern"
@@ -286,14 +287,22 @@ type ClientOptions struct {
 	// encryption.
 	//
 	// Deprecated: This option is for internal use only and should not be set (see GODRIVER-2149). It may be
-	// changed or removed in any release.
+	// changed in any release. This option will be removed in 3.0 and replaced with the Custom options.Options
+	// pattern: SetInternalClientOptions(clientOptions, "crypt", myCrypt)
 	Crypt driver.Crypt
 
 	// Deployment specifies a custom deployment to use for the new Client.
 	//
+	// Deprecated: This option is for internal use only and should not be set. It may be changed in any release.
+	// This option will be removed in 3.0 and replaced with the Custom options.Options pattern:
+	// SetInternalClientOptions(clientOptions, "deployment", myDeployment)
+	Deployment driver.Deployment
+
+	// Custom specifies internal options for the new Client.
+	//
 	// Deprecated: This option is for internal use only and should not be set. It may be changed or removed in any
 	// release.
-	Deployment driver.Deployment
+	Custom options.Options
 
 	connString *connstring.ConnString
 	err        error

mongo/options/clientoptions_test.go

@@ -27,6 +27,7 @@ import (
 	"go.mongodb.org/mongo-driver/v2/event"
 	"go.mongodb.org/mongo-driver/v2/internal/assert"
 	"go.mongodb.org/mongo-driver/v2/internal/httputil"
+	"go.mongodb.org/mongo-driver/v2/internal/options"
 	"go.mongodb.org/mongo-driver/v2/internal/ptrutil"
 	"go.mongodb.org/mongo-driver/v2/mongo/readconcern"
 	"go.mongodb.org/mongo-driver/v2/mongo/readpref"
@@ -156,6 +157,7 @@ func TestClientOptions(t *testing.T) {
 				cmp.Comparer(func(r1, r2 *bson.Registry) bool { return r1 == r2 }),
 				cmp.Comparer(func(cfg1, cfg2 *tls.Config) bool { return cfg1 == cfg2 }),
 				cmp.Comparer(func(fp1, fp2 *event.PoolMonitor) bool { return fp1 == fp2 }),
+				cmp.Comparer(options.Equal),
 				cmp.AllowUnexported(ClientOptions{}),
 				cmpopts.IgnoreFields(http.Client{}, "Transport"),
 			); diff != "" {
@@ -1253,6 +1255,7 @@ func TestApplyURI(t *testing.T) {
 				cmp.Comparer(func(r1, r2 *bson.Registry) bool { return r1 == r2 }),
 				cmp.Comparer(compareTLSConfig),
 				cmp.Comparer(compareErrors),
+				cmp.Comparer(options.Equal),
 				cmpopts.SortSlices(stringLess),
 				cmpopts.IgnoreFields(connstring.ConnString{}, "SSLClientCertificateKeyPassword"),
 				cmpopts.IgnoreFields(http.Client{}, "Transport"),

x/mongo/driver/xoptions/options.go

@@ -0,0 +1,38 @@
+// Copyright (C) MongoDB, Inc. 2025-present.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package xoptions
+
+import (
+	"fmt"
+
+	"go.mongodb.org/mongo-driver/v2/mongo/options"
+	"go.mongodb.org/mongo-driver/v2/x/mongo/driver"
+)
+
+// SetInternalClientOptions sets internal options for ClientOptions.
+//
+// Deprecated: This function is for internal use only. It may be changed or removed in any release.
+func SetInternalClientOptions(opts *options.ClientOptions, key string, option any) error {
+	const typeErr = "unexpected type for %s"
+	switch key {
+	case "crypt":
+		c, ok := option.(driver.Crypt)
+		if !ok {
+			return fmt.Errorf(typeErr, key)
+		}
+		opts.Crypt = c
+	case "deployment":
+		d, ok := option.(driver.Deployment)
+		if !ok {
+			return fmt.Errorf(typeErr, key)
+		}
+		opts.Deployment = d
+	default:
+		return fmt.Errorf("unsupported option: %s", key)
+	}
+	return nil
+}

x/mongo/driver/xoptions/options_test.go

@@ -0,0 +1,64 @@
+// Copyright (C) MongoDB, Inc. 2025-present.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package xoptions
+
+import (
+	"testing"
+
+	"go.mongodb.org/mongo-driver/v2/internal/require"
+	"go.mongodb.org/mongo-driver/v2/mongo/options"
+	"go.mongodb.org/mongo-driver/v2/x/mongo/driver"
+	"go.mongodb.org/mongo-driver/v2/x/mongo/driver/drivertest"
+)
+
+func TestSetInternalClientOptions(t *testing.T) {
+	t.Parallel()
+
+	t.Run("set crypt", func(t *testing.T) {
+		t.Parallel()
+
+		c := driver.NewCrypt(&driver.CryptOptions{})
+		opts := options.Client()
+		err := SetInternalClientOptions(opts, "crypt", c)
+		require.NoError(t, err, "error setting crypt: %v", err)
+		require.Equal(t, c, opts.Crypt, "expected %v, got %v", c, opts.Crypt)
+	})
+
+	t.Run("set crypt - wrong type", func(t *testing.T) {
+		t.Parallel()
+
+		opts := options.Client()
+		err := SetInternalClientOptions(opts, "crypt", &drivertest.MockDeployment{})
+		require.EqualError(t, err, "unexpected type for crypt")
+	})
+
+	t.Run("set deployment", func(t *testing.T) {
+		t.Parallel()
+
+		d := &drivertest.MockDeployment{}
+		opts := options.Client()
+		err := SetInternalClientOptions(opts, "deployment", d)
+		require.NoError(t, err, "error setting deployment: %v", err)
+		require.Equal(t, d, opts.Deployment, "expected %v, got %v", d, opts.Deployment)
+	})
+
+	t.Run("set deployment - wrong type", func(t *testing.T) {
+		t.Parallel()
+
+		opts := options.Client()
+		err := SetInternalClientOptions(opts, "deployment", driver.NewCrypt(&driver.CryptOptions{}))
+		require.EqualError(t, err, "unexpected type for deployment")
+	})
+
+	t.Run("set unsupported option", func(t *testing.T) {
+		t.Parallel()
+
+		opts := options.Client()
+		err := SetInternalClientOptions(opts, "unsupported", "unsupported")
+		require.EqualError(t, err, "unsupported option: unsupported")
+	})
+}