Nullable improvments for StringExtensions.

src/Open.IdentityServer/src/Extensions/StringsExtensions.cs

@@ -7,10 +7,13 @@
 using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Text;
 using System.Text.Encodings.Web;
 
+#nullable enable
+
 namespace Open.IdentityServer.Extensions;
 
 internal static class StringExtensions
@@ -47,7 +50,7 @@ public static IEnumerable<string> FromSpaceSeparatedString(this string input)
         return input.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).ToList();
     }
 
-    public static List<string> ParseScopesString(this string scopes)
+    public static List<string>? ParseScopesString(this string? scopes)
     {
         if (scopes.IsMissing())
         {
@@ -67,13 +70,13 @@ public static List<string> ParseScopesString(this string scopes)
     }
 
     [DebuggerStepThrough]
-    public static bool IsMissing(this string value)
+    public static bool IsMissing([NotNullWhen(false)] this string? value)
     {
         return string.IsNullOrWhiteSpace(value);
     }
 
     [DebuggerStepThrough]
-    public static bool IsMissingOrTooLong(this string value, int maxLength)
+    public static bool IsMissingOrTooLong(this string? value, int maxLength)
     {
         if (string.IsNullOrWhiteSpace(value))
         {
@@ -89,13 +92,13 @@ public static bool IsMissingOrTooLong(this string value, int maxLength)
     }
 
     [DebuggerStepThrough]
-    public static bool IsPresent(this string value)
+    public static bool IsPresent([NotNullWhen(true)] this string? value)
     {
         return !string.IsNullOrWhiteSpace(value);
     }
 
     [DebuggerStepThrough]
-    public static string EnsureLeadingSlash(this string url)
+    public static string? EnsureLeadingSlash(this string? url)
     {
         if (url != null && !url.StartsWith("/"))
         {
@@ -106,7 +109,7 @@ public static string EnsureLeadingSlash(this string url)
     }
 
     [DebuggerStepThrough]
-    public static string EnsureTrailingSlash(this string url)
+    public static string? EnsureTrailingSlash(this string? url)
     {
         if (url != null && !url.EndsWith("/"))
         {
@@ -117,7 +120,7 @@ public static string EnsureTrailingSlash(this string url)
     }
 
     [DebuggerStepThrough]
-    public static string RemoveLeadingSlash(this string url)
+    public static string? RemoveLeadingSlash(this string? url)
     {
         if (url != null && url.StartsWith("/"))
         {
@@ -128,7 +131,7 @@ public static string RemoveLeadingSlash(this string url)
     }
 
     [DebuggerStepThrough]
-    public static string RemoveTrailingSlash(this string url)
+    public static string? RemoveTrailingSlash(this string? url)
     {
         if (url != null && url.EndsWith("/"))
         {
@@ -139,9 +142,9 @@ public static string RemoveTrailingSlash(this string url)
     }
 
     [DebuggerStepThrough]
-    public static string CleanUrlPath(this string url)
+    public static string CleanUrlPath(this string? url)
     {
-        if (String.IsNullOrWhiteSpace(url)) url = "/";
+        if (string.IsNullOrWhiteSpace(url)) url = "/";
 
         if (url != "/" && url.EndsWith("/"))
         {
@@ -153,7 +156,7 @@ public static string CleanUrlPath(this string url)
 
     [DebuggerStepThrough]
     // Clone of UrlHelperBase.CheckIsLocalUrl from https://github.com/dotnet/aspnetcore/blob/3f1acb59718cadf111a0a796681e3d3509bb3381/src/Mvc/Mvc.Core/src/Routing/UrlHelperBase.cs
-    public static bool IsLocalUrl(this string url)
+    public static bool IsLocalUrl(this string? url)
     {
         if (string.IsNullOrEmpty(url))
         {
@@ -246,7 +249,7 @@ public static string AddHashFragment(this string url, string query)
     }
 
     [DebuggerStepThrough]
-    public static NameValueCollection ReadQueryStringAsNameValueCollection(this string url)
+    public static NameValueCollection ReadQueryStringAsNameValueCollection(this string? url)
     {
         if (url != null)
         {
@@ -266,7 +269,7 @@ public static NameValueCollection ReadQueryStringAsNameValueCollection(this stri
         return new NameValueCollection();
     }
 
-    public static string GetOrigin(this string url)
+    public static string? GetOrigin(this string? url)
     {
         if (url != null)
         {

src/Open.IdentityServer/test/Open.IdentityServer.IntegrationTests/Utility/InternalStringExtensions.cs

@@ -1,4 +1,5 @@
 // Copyright (c) Brock Allen & Dominick Baier. All rights reserved.
+// Modified by Rock Solid Knowledge Ltd. Copyright in modifications 2026, Rock Solid Knowledge Ltd.
 // Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
 #nullable enable
 
@@ -11,13 +12,13 @@ namespace IdentityServer.IntegrationTests.Utility;
 internal static class InternalStringExtensions
 {
     [DebuggerStepThrough]
-    public static bool IsMissing(this string value)
+    public static bool IsMissing([NotNullWhen(false)] this string? value)
     {
         return string.IsNullOrWhiteSpace(value);
     }
 
     [DebuggerStepThrough]
-    public static bool IsPresent(this string value)
+    public static bool IsPresent([NotNullWhen(true)] this string? value)
     {
         return !(value.IsMissing());
     }

src/Storage/src/Extensions/StringsExtensions.cs

@@ -1,21 +1,25 @@
 // Copyright (c) Brock Allen & Dominick Baier. All rights reserved.
+// Modified by Rock Solid Knowledge Ltd. Copyright in modifications 2026, Rock Solid Knowledge Ltd.
 // Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
 
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+#nullable enable
 
 namespace Open.IdentityServer.Extensions;
 
 internal static class StringExtensions
 {
     [DebuggerStepThrough]
-    public static bool IsMissing(this string value)
+    public static bool IsMissing([NotNullWhen(false)] this string? value)
     {
         return string.IsNullOrWhiteSpace(value);
     }
 
     [DebuggerStepThrough]
-    public static bool IsPresent(this string value)
+    public static bool IsPresent([NotNullWhen(true)] this string? value)
     {
         return !string.IsNullOrWhiteSpace(value);
     }