Introduce a new Import method in the handler descriptors

src/OpenIddict.Abstractions/Resources/OpenIddictResources.resx

@@ -1389,6 +1389,10 @@ To register the OpenIddict core services, reference the 'OpenIddict.Core' packag
     <value>Provided symmetric key was incorrect size. Expected {0} bits, received {1}.</value>
     <comment>{Locked}</comment>
   </data>
+  <data name="ID0284" xml:space="preserve">
+    <value>The context type associated with the specified descriptor doesn't match the context type of this builder.</value>
+    <comment>{Locked}</comment>
+  </data>
   <data name="ID2000" xml:space="preserve">
     <value>The security token is missing.</value>
   </data>

src/OpenIddict.Server/OpenIddictServerBuilder.cs

@@ -157,8 +157,7 @@ namespace Microsoft.Extensions.DependencyInjection
         /// <summary>
         /// Registers an encryption key.
         /// </summary>
-        /// <param name="key">The security key.
-        /// </param>
+        /// <param name="key">The security key.</param>
         /// <returns>The <see cref="OpenIddictServerBuilder"/>.</returns>
         public OpenIddictServerBuilder AddEncryptionKey(SecurityKey key)
         {

src/OpenIddict.Server/OpenIddictServerHandlerDescriptor.cs

@@ -68,7 +68,7 @@ namespace OpenIddict.Server
         public class Builder<TContext> where TContext : BaseContext
         {
             private ServiceDescriptor? _descriptor;
-            private readonly List<Type> _filterTypes = new List<Type>();
+            private readonly List<Type> _filters = new();
             private int _order;
             private OpenIddictServerHandlerType _type;
 
@@ -89,7 +89,7 @@ namespace OpenIddict.Server
                     throw new InvalidOperationException(SR.GetResourceString(SR.ID0104));
                 }
 
-                _filterTypes.Add(type);
+                _filters.Add(type);
 
                 return this;
             }
@@ -103,6 +103,33 @@ namespace OpenIddict.Server
                 where TFilter : IOpenIddictServerHandlerFilter<TContext>
                 => AddFilter(typeof(TFilter));
 
+            /// <summary>
+            /// Imports the properties set on the specified descriptor.
+            /// </summary>
+            /// <param name="descriptor">The existing descriptor properties are copied from.</param>
+            /// <remarks>All the properties previously set on this instance are automatically replaced.</remarks>
+            /// <returns>The builder instance, so that calls can be easily chained.</returns>
+            public Builder<TContext> Import(OpenIddictServerHandlerDescriptor descriptor)
+            {
+                if (descriptor is null)
+                {
+                    throw new ArgumentNullException(nameof(descriptor));
+                }
+
+                if (descriptor.ContextType != typeof(TContext))
+                {
+                    throw new InvalidOperationException(SR.GetResourceString(SR.ID0284));
+                }
+
+                _descriptor = descriptor.ServiceDescriptor;
+                _filters.Clear();
+                _filters.AddRange(descriptor.FilterTypes);
+                _order = descriptor.Order;
+                _type = descriptor.Type;
+
+                return this;
+            }
+
             /// <summary>
             /// Sets the service descriptor.
             /// </summary>
@@ -250,7 +277,7 @@ namespace OpenIddict.Server
             public OpenIddictServerHandlerDescriptor Build() => new OpenIddictServerHandlerDescriptor
             {
                 ContextType = typeof(TContext),
-                FilterTypes = _filterTypes.ToImmutableArray(),
+                FilterTypes = _filters.ToImmutableArray(),
                 Order = _order,
                 ServiceDescriptor = _descriptor ?? throw new InvalidOperationException(SR.GetResourceString(SR.ID0105)),
                 Type = _type

src/OpenIddict.Server/OpenIddictServerHandlers.Authentication.cs

@@ -1150,11 +1150,7 @@ namespace OpenIddict.Server
             {
                 private readonly IOpenIddictScopeManager? _scopeManager;
 
-                public ValidateScopes()
-                {
-                }
-
-                public ValidateScopes(IOpenIddictScopeManager scopeManager)
+                public ValidateScopes(IOpenIddictScopeManager? scopeManager = null)
                     => _scopeManager = scopeManager;
 
                 /// <summary>
@@ -1163,7 +1159,7 @@ namespace OpenIddict.Server
                 public static OpenIddictServerHandlerDescriptor Descriptor { get; }
                     = OpenIddictServerHandlerDescriptor.CreateBuilder<ValidateAuthorizationRequestContext>()
                         .AddFilter<RequireScopeValidationEnabled>()
-                        .UseScopedHandler<ValidateScopes>(provider =>
+                        .UseScopedHandler<ValidateScopes>(static provider =>
                         {
                             // Note: the scope manager is only resolved if the degraded mode was not enabled to ensure
                             // invalid core configuration exceptions are not thrown even if the managers were registered.

src/OpenIddict.Server/OpenIddictServerHandlers.Device.cs

@@ -372,11 +372,7 @@ namespace OpenIddict.Server
             {
                 private readonly IOpenIddictScopeManager? _scopeManager;
 
-                public ValidateScopes()
-                {
-                }
-
-                public ValidateScopes(IOpenIddictScopeManager scopeManager)
+                public ValidateScopes(IOpenIddictScopeManager? scopeManager = null)
                     => _scopeManager = scopeManager;
 
                 /// <summary>
@@ -385,7 +381,7 @@ namespace OpenIddict.Server
                 public static OpenIddictServerHandlerDescriptor Descriptor { get; }
                     = OpenIddictServerHandlerDescriptor.CreateBuilder<ValidateDeviceRequestContext>()
                         .AddFilter<RequireScopeValidationEnabled>()
-                        .UseScopedHandler<ValidateScopes>(provider =>
+                        .UseScopedHandler<ValidateScopes>(static provider =>
                         {
                             // Note: the scope manager is only resolved if the degraded mode was not enabled to ensure
                             // invalid core configuration exceptions are not thrown even if the managers were registered.

src/OpenIddict.Server/OpenIddictServerHandlers.Exchange.cs

@@ -701,11 +701,7 @@ namespace OpenIddict.Server
             {
                 private readonly IOpenIddictScopeManager? _scopeManager;
 
-                public ValidateScopes()
-                {
-                }
-
-                public ValidateScopes(IOpenIddictScopeManager scopeManager)
+                public ValidateScopes(IOpenIddictScopeManager? scopeManager = null)
                     => _scopeManager = scopeManager;
 
                 /// <summary>
@@ -714,7 +710,7 @@ namespace OpenIddict.Server
                 public static OpenIddictServerHandlerDescriptor Descriptor { get; }
                     = OpenIddictServerHandlerDescriptor.CreateBuilder<ValidateTokenRequestContext>()
                         .AddFilter<RequireScopeValidationEnabled>()
-                        .UseScopedHandler<ValidateScopes>(provider =>
+                        .UseScopedHandler<ValidateScopes>(static provider =>
                         {
                             // Note: the scope manager is only resolved if the degraded mode was not enabled to ensure
                             // invalid core configuration exceptions are not thrown even if the managers were registered.

src/OpenIddict.Validation/OpenIddictValidationHandlerDescriptor.cs

@@ -68,7 +68,7 @@ namespace OpenIddict.Validation
         public class Builder<TContext> where TContext : BaseContext
         {
             private ServiceDescriptor? _descriptor;
-            private readonly List<Type> _filterTypes = new List<Type>();
+            private readonly List<Type> _filters = new();
             private int _order;
             private OpenIddictValidationHandlerType _type;
 
@@ -89,7 +89,7 @@ namespace OpenIddict.Validation
                     throw new InvalidOperationException(SR.GetResourceString(SR.ID0104));
                 }
 
-                _filterTypes.Add(type);
+                _filters.Add(type);
 
                 return this;
             }
@@ -103,6 +103,33 @@ namespace OpenIddict.Validation
                 where TFilter : IOpenIddictValidationHandlerFilter<TContext>
                 => AddFilter(typeof(TFilter));
 
+            /// <summary>
+            /// Imports the properties set on the specified descriptor.
+            /// </summary>
+            /// <param name="descriptor">The existing descriptor properties are copied from.</param>
+            /// <remarks>All the properties previously set on this instance are automatically replaced.</remarks>
+            /// <returns>The builder instance, so that calls can be easily chained.</returns>
+            public Builder<TContext> Import(OpenIddictValidationHandlerDescriptor descriptor)
+            {
+                if (descriptor is null)
+                {
+                    throw new ArgumentNullException(nameof(descriptor));
+                }
+
+                if (descriptor.ContextType != typeof(TContext))
+                {
+                    throw new InvalidOperationException(SR.GetResourceString(SR.ID0284));
+                }
+
+                _descriptor = descriptor.ServiceDescriptor;
+                _filters.Clear();
+                _filters.AddRange(descriptor.FilterTypes);
+                _order = descriptor.Order;
+                _type = descriptor.Type;
+
+                return this;
+            }
+
             /// <summary>
             /// Sets the service descriptor.
             /// </summary>
@@ -250,7 +277,7 @@ namespace OpenIddict.Validation
             public OpenIddictValidationHandlerDescriptor Build() => new OpenIddictValidationHandlerDescriptor
             {
                 ContextType = typeof(TContext),
-                FilterTypes = _filterTypes.ToImmutableArray(),
+                FilterTypes = _filters.ToImmutableArray(),
                 Order = _order,
                 ServiceDescriptor = _descriptor ?? throw new InvalidOperationException(SR.GetResourceString(SR.ID0105)),
                 Type = _type