feat: add back Clear for legacy IPNetwork

Author: WeihanLi

src/DefaultBuilder/src/ForwardedHeadersOptionsSetup.cs

@@ -27,7 +27,10 @@ public void Configure(ForwardedHeadersOptions options)
         options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
         // Only loopback proxies are allowed by default. Clear that restriction because forwarders are
         // being enabled by explicit configuration.
+#pragma warning disable CS0618 // Type or member is obsolete
         options.KnownNetworks.Clear();
+#pragma warning restore CS0618 // Type or member is obsolete
+        options.KnownIPNetworks.Clear();
         options.KnownProxies.Clear();
     }
 }

src/Middleware/HttpOverrides/src/ForwardedHeadersOptions.cs

@@ -84,14 +84,15 @@ public class ForwardedHeadersOptions
 
     /// <summary>
     /// Address ranges of known proxies to accept forwarded headers from.
+    /// Obsolete, please use <see cref="KnownIPNetworks"/> instead
     /// </summary>
     [Obsolete("Please use KnownIPNetworks instead")]
-    public IList<AspNetIPNetwork> KnownNetworks { get; } = new List<AspNetIPNetwork>() { new AspNetIPNetwork(IPAddress.Loopback, 8) };
+    public IList<AspNetIPNetwork> KnownNetworks { get; } = new List<AspNetIPNetwork>() { new(IPAddress.Loopback, 8) };
 
     /// <summary>
     /// Address ranges of known proxies to accept forwarded headers from.
     /// </summary>
-    public IList<IPNetwork> KnownIPNetworks { get; } = new List<IPNetwork>() { new IPNetwork(IPAddress.Loopback, 8) };
+    public IList<IPNetwork> KnownIPNetworks { get; } = new List<IPNetwork>() { new(IPAddress.Loopback, 8) };
 
     /// <summary>
     /// The allowed values from x-forwarded-host. If the list is empty then all hosts are allowed.

src/Middleware/HttpOverrides/test/ForwardedHeadersMiddlewareTest.cs

@@ -120,6 +120,9 @@ public async Task XForwardedForForwardLimit(int limit, string header, string exp
                         ForwardLimit = limit,
                     };
                     options.KnownProxies.Clear();
+#pragma warning disable CS0618 // Type or member is obsolete
+                    options.KnownNetworks.Clear();
+#pragma warning restore CS0618 // Type or member is obsolete
                     options.KnownIPNetworks.Clear();
                     app.UseForwardedHeaders(options);
                 });
@@ -861,6 +864,9 @@ public async Task XForwardedProtoOverrideLimitedByLoopback(string protoHeader, s
                     };
                     if (!loopback)
                     {
+#pragma warning disable CS0618 // Type or member is obsolete
+                        options.KnownNetworks.Clear();
+#pragma warning restore CS0618 // Type or member is obsolete
                         options.KnownIPNetworks.Clear();
                         options.KnownProxies.Clear();
                     }
@@ -1134,6 +1140,9 @@ public async Task ForwardersWithDIOptionsRunsOnce(int limit, string header, stri
                     {
                         options.ForwardedHeaders = ForwardedHeaders.XForwardedProto;
                         options.KnownProxies.Clear();
+#pragma warning disable CS0618 // Type or member is obsolete
+                        options.KnownNetworks.Clear();
+#pragma warning restore CS0618 // Type or member is obsolete
                         options.KnownIPNetworks.Clear();
                         options.ForwardLimit = limit;
                     });
@@ -1176,6 +1185,9 @@ public async Task ForwardersWithDirectOptionsRunsTwice(int limit, string header,
                         ForwardLimit = limit,
                     };
                     options.KnownProxies.Clear();
+#pragma warning disable CS0618 // Type or member is obsolete
+                    options.KnownNetworks.Clear();
+#pragma warning restore CS0618 // Type or member is obsolete
                     options.KnownIPNetworks.Clear();
                     app.UseForwardedHeaders(options);
                     app.UseForwardedHeaders(options);

src/Middleware/HttpOverrides/test/IPNetworkTest.cs

@@ -4,7 +4,7 @@
 
 namespace Microsoft.AspNetCore.HttpOverrides;
 
-[System.Obsolete]
+[Obsolete("IPNetwork is obsolete")]
 public class IPNetworkTest
 {
     [Theory]