Obsolete ServicePointManager 🎉 (#103456)

* Obsolete ServicePointManager

* Tweak obsoletion message on ServicePointManager

Author: MihaZupan

src/libraries/Common/src/System/Net/TlsStream.cs

@@ -8,6 +8,9 @@
 using System.Threading;
 using System.Threading.Tasks;
 
+#pragma warning disable SYSLIB0014 // ServicePointManager is obsolete
+// This type is used by FtpWebRequest (already obsolete) and SmtpClient (discouraged).
+
 namespace System.Net
 {
     internal sealed class TlsStream : NetworkStream

src/libraries/System.Net.HttpListener/src/System/Net/Managed/HttpConnection.cs

@@ -30,6 +30,7 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
+using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net.Security;
@@ -100,7 +101,11 @@ public HttpConnection(Socket sock, HttpEndPointListener epl, bool secure, X509Ce
             }
 
             _timer = new Timer(OnTimeout, null, Timeout.Infinite, Timeout.Infinite);
+
+#pragma warning disable SYSLIB0014 // ServicePointManager is obsolete
             _sslStream?.AuthenticateAsServer(_cert, true, (SslProtocols)ServicePointManager.SecurityProtocol, false);
+#pragma warning restore SYSLIB0014
+
             Init();
         }
 

src/libraries/System.Net.Requests/ref/System.Net.Requests.cs

@@ -486,6 +486,7 @@ internal ServicePoint() { }
         public bool CloseConnectionGroup(string connectionGroupName) { throw null; }
         public void SetTcpKeepAlive(bool enabled, int keepAliveTime, int keepAliveInterval) { }
     }
+    [System.ObsoleteAttribute("WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead. Settings on ServicePointManager no longer affect SslStream or HttpClient.", DiagnosticId = "SYSLIB0014", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
     public partial class ServicePointManager
     {
         internal ServicePointManager() { }
@@ -504,11 +505,8 @@ internal ServicePointManager() { }
         public static System.Net.SecurityProtocolType SecurityProtocol { get { throw null; } set { } }
         public static System.Net.Security.RemoteCertificateValidationCallback? ServerCertificateValidationCallback { get { throw null; } set { } }
         public static bool UseNagleAlgorithm { get { throw null; } set { } }
-        [System.ObsoleteAttribute("WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.", DiagnosticId = "SYSLIB0014", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
         public static System.Net.ServicePoint FindServicePoint(string uriString, System.Net.IWebProxy? proxy) { throw null; }
-        [System.ObsoleteAttribute("WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.", DiagnosticId = "SYSLIB0014", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
         public static System.Net.ServicePoint FindServicePoint(System.Uri address) { throw null; }
-        [System.ObsoleteAttribute("WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.", DiagnosticId = "SYSLIB0014", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
         public static System.Net.ServicePoint FindServicePoint(System.Uri address, System.Net.IWebProxy? proxy) { throw null; }
         public static void SetTcpKeepAlive(bool enabled, int keepAliveTime, int keepAliveInterval) { }
     }

src/libraries/System.Net.Requests/src/System/Net/FileWebRequest.cs

@@ -9,6 +9,8 @@
 
 namespace System.Net
 {
+    // NOTE: While this class is not explicitly marked as obsolete,
+    // it effectively is by virtue of WebRequest.Create being obsolete.
     public class FileWebRequest : WebRequest, ISerializable
     {
         private readonly WebHeaderCollection _headers = new WebHeaderCollection();

src/libraries/System.Net.Requests/src/System/Net/FtpWebRequest.cs

@@ -176,6 +176,9 @@ internal static FtpMethodInfo GetMethodInfo(string method)
         };
     }
 
+    // NOTE: While this class is not explicitly marked as obsolete,
+    // it effectively is by virtue of WebRequest.Create being obsolete.
+
     /// <summary>
     /// The FtpWebRequest class implements a basic FTP client interface.
     /// </summary>

src/libraries/System.Net.Requests/src/System/Net/HttpWebRequest.cs

@@ -26,6 +26,8 @@ namespace System.Net
 {
     public delegate void HttpContinueDelegate(int StatusCode, WebHeaderCollection httpHeaders);
 
+    // NOTE: While this class is not explicitly marked as obsolete,
+    // it effectively is by virtue of WebRequest.Create being obsolete.
     public class HttpWebRequest : WebRequest, ISerializable
     {
         private const int DefaultContinueTimeout = 350; // Current default value from .NET Desktop.

src/libraries/System.Net.Requests/src/System/Net/ServicePoint/ServicePoint.cs

@@ -7,6 +7,9 @@
 
 namespace System.Net
 {
+    // NOTE: While this class is not explicitly marked as obsolete,
+    // it effectively is by virtue of ServicePointManager being obsolete,
+    // where ServicePointManager is the only way to obtain ServicePoint instances.
     public class ServicePoint
     {
         private int _connectionLeaseTimeout = -1;

src/libraries/System.Net.Requests/src/System/Net/ServicePoint/ServicePointManager.cs

@@ -9,6 +9,7 @@
 
 namespace System.Net
 {
+    [Obsolete(Obsoletions.WebRequestMessage + " Settings on ServicePointManager no longer affect SslStream or HttpClient.", DiagnosticId = Obsoletions.WebRequestDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
     public class ServicePointManager
     {
         public const int DefaultNonPersistentConnectionLimit = 4;
@@ -99,13 +100,10 @@ public static int DnsRefreshTimeout
         [UnsupportedOSPlatform("browser")]
         public static EncryptionPolicy EncryptionPolicy { get; } = EncryptionPolicy.RequireEncryption;
 
-        [Obsolete(Obsoletions.WebRequestMessage, DiagnosticId = Obsoletions.WebRequestDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
         public static ServicePoint FindServicePoint(Uri address) => FindServicePoint(address, null);
 
-        [Obsolete(Obsoletions.WebRequestMessage, DiagnosticId = Obsoletions.WebRequestDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
         public static ServicePoint FindServicePoint(string uriString, IWebProxy? proxy) => FindServicePoint(new Uri(uriString), proxy);
 
-        [Obsolete(Obsoletions.WebRequestMessage, DiagnosticId = Obsoletions.WebRequestDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
         public static ServicePoint FindServicePoint(Uri address, IWebProxy? proxy)
         {
             ArgumentNullException.ThrowIfNull(address);

src/libraries/System.Net.Requests/src/System/Net/WebRequest.cs

@@ -15,6 +15,8 @@
 using System.Threading.Tasks;
 namespace System.Net
 {
+    // NOTE: While this class is not explicitly marked as obsolete,
+    // it effectively is by virtue of WebRequest.Create being obsolete.
     public abstract class WebRequest : MarshalByRefObject, ISerializable
     {
         internal sealed class WebRequestPrefixElement