Turn on nullability for Routing (#24238)

* Turn on nullability for Routing

We previously only had annotations enabled which resulted in incorrect nullability. This change enables
nullability.

Fixes #24042

Author: pranavkm

src/Http/Http.Abstractions/src/Routing/Endpoint.cs

@@ -20,8 +20,8 @@ public class Endpoint
         /// </param>
         public Endpoint(
             RequestDelegate requestDelegate,
-            EndpointMetadataCollection metadata,
-            string displayName)
+            EndpointMetadataCollection? metadata,
+            string? displayName)
         {
             // All are allowed to be null
             RequestDelegate = requestDelegate;
@@ -32,7 +32,7 @@ public Endpoint(
         /// <summary>
         /// Gets the informational display name of this endpoint.
         /// </summary>
-        public string DisplayName { get; }
+        public string? DisplayName { get; }
 
         /// <summary>
         /// Gets the collection of metadata associated with this endpoint.

src/Http/Routing.Abstractions/src/IRouteConstraint.cs

@@ -25,7 +25,7 @@ public interface IRouteConstraint : IParameterPolicy
         /// <returns><c>true</c> if the URL parameter contains a valid value; otherwise, <c>false</c>.</returns>
         bool Match(
             HttpContext? httpContext,
-            IRouter route,
+            IRouter? route,
             string routeKey,
             RouteValueDictionary values,
             RouteDirection routeDirection);

src/Http/Routing/src/ArrayBuilder.cs

@@ -6,6 +6,7 @@
 // 
 // See https://github.com/dotnet/corefx/blob/143df51926f2ad397fef9c9ca7ede88e2721e801/src/Common/src/System/Collections/Generic/ArrayBuilder.cs 
 
+#nullable disable
 
 using System;
 using System.Diagnostics;

src/Http/Routing/src/Builder/EndpointRoutingApplicationBuilderExtensions.cs

@@ -128,7 +128,7 @@ private static void VerifyEndpointRoutingMiddlewareIsRegistered(IApplicationBuil
             }
 
             // If someone messes with this, just let it crash.
-            endpointRouteBuilder = (DefaultEndpointRouteBuilder)obj;
+            endpointRouteBuilder = (DefaultEndpointRouteBuilder)obj!;
 
             // This check handles the case where Map or something else that forks the pipeline is called between the two
             // routing middleware.

src/Http/Routing/src/CompositeEndpointDataSource.cs

@@ -1,11 +1,12 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Text;
 using System.Threading;
@@ -21,8 +22,8 @@ namespace Microsoft.AspNetCore.Routing
     public sealed class CompositeEndpointDataSource : EndpointDataSource
     {
         private readonly object _lock;
-        private readonly ICollection<EndpointDataSource> _dataSources;
-        private IReadOnlyList<Endpoint> _endpoints;
+        private readonly ICollection<EndpointDataSource> _dataSources = default!;
+        private IReadOnlyList<Endpoint> _endpoints = default!;
         private IChangeToken _consumerChangeToken;
         private CancellationTokenSource _cts;
 
@@ -49,7 +50,7 @@ public CompositeEndpointDataSource(IEnumerable<EndpointDataSource> endpointDataS
             }
         }
 
-        private void OnDataSourcesChanged(object sender, NotifyCollectionChangedEventArgs e)
+        private void OnDataSourcesChanged(object? sender, NotifyCollectionChangedEventArgs e)
         {
             lock (_lock)
             {
@@ -140,6 +141,7 @@ private void HandleChange()
             }
         }
 
+        [MemberNotNull(nameof(_cts), nameof(_consumerChangeToken))]
         private void CreateChangeToken()
         {
             _cts = new CancellationTokenSource();
@@ -198,7 +200,7 @@ private string DebuggerDisplayString
                 }
                 return sb.ToString();
 
-                IEnumerable<string> FormatValues(IEnumerable<KeyValuePair<string, object>> values)
+                IEnumerable<string> FormatValues(IEnumerable<KeyValuePair<string, object?>> values)
                 {
                     return values.Select(
                         kvp =>

src/Http/Routing/src/Constraints/BoolRouteConstraint.cs

@@ -14,8 +14,8 @@ public class BoolRouteConstraint : IRouteConstraint
     {
         /// <inheritdoc />
         public bool Match(
-            HttpContext httpContext,
-            IRouter route,
+            HttpContext? httpContext,
+            IRouter? route,
             string routeKey,
             RouteValueDictionary values,
             RouteDirection routeDirection)
@@ -44,4 +44,4 @@ public bool Match(
             return false;
         }
     }
-}
+}

src/Http/Routing/src/Constraints/CompositeRouteConstraint.cs

@@ -33,8 +33,8 @@ public CompositeRouteConstraint(IEnumerable<IRouteConstraint> constraints)
 
         /// <inheritdoc />
         public bool Match(
-            HttpContext httpContext,
-            IRouter route,
+            HttpContext? httpContext,
+            IRouter? route,
             string routeKey,
             RouteValueDictionary values,
             RouteDirection routeDirection)
@@ -60,4 +60,4 @@ public bool Match(
             return true;
         }
     }
-}
+}

src/Http/Routing/src/Constraints/DateTimeRouteConstraint.cs

@@ -20,8 +20,8 @@ public class DateTimeRouteConstraint : IRouteConstraint
     {
         /// <inheritdoc />
         public bool Match(
-            HttpContext httpContext,
-            IRouter route,
+            HttpContext? httpContext,
+            IRouter? route,
             string routeKey,
             RouteValueDictionary values,
             RouteDirection routeDirection)
@@ -50,4 +50,4 @@ public bool Match(
             return false;
         }
     }
-}
+}

src/Http/Routing/src/Constraints/DecimalRouteConstraint.cs

@@ -14,8 +14,8 @@ public class DecimalRouteConstraint : IRouteConstraint
     {
         /// <inheritdoc />
         public bool Match(
-            HttpContext httpContext,
-            IRouter route,
+            HttpContext? httpContext,
+            IRouter? route,
             string routeKey,
             RouteValueDictionary values,
             RouteDirection routeDirection)
@@ -44,4 +44,4 @@ public bool Match(
             return false;
         }
     }
-}
+}

src/Http/Routing/src/Constraints/DoubleRouteConstraint.cs

@@ -14,8 +14,8 @@ public class DoubleRouteConstraint : IRouteConstraint
     {
         /// <inheritdoc />
         public bool Match(
-            HttpContext httpContext,
-            IRouter route,
+            HttpContext? httpContext,
+            IRouter? route,
             string routeKey,
             RouteValueDictionary values,
             RouteDirection routeDirection)
@@ -48,4 +48,4 @@ public bool Match(
             return false;
         }
     }
-}
+}