Fix NatsUri not reflecting host/port changes from OnConnectingAsync hook

src/NATS.Client.Core/Internal/NatsUri.cs

@@ -4,8 +4,6 @@ internal sealed record NatsUri
 {
     public const string DefaultScheme = "nats";
 
-    private readonly string _redacted;
-
     public NatsUri(string urlString, bool isSeed, string defaultScheme = DefaultScheme)
     {
         IsSeed = isSeed;
@@ -40,6 +38,23 @@ public NatsUri(string urlString, bool isSeed, string defaultScheme = DefaultSche
         }
 
         Uri = uriBuilder.Uri;
+    }
+
+    public Uri Uri { get; init; }
+
+    public bool IsSeed { get; }
+
+    public bool IsTls { get; }
+
+    public bool IsWebSocket { get; }
+
+    public string Host => Uri.Host;
+
+    public int Port => Uri.Port;
+
+    public override string ToString()
+    {
+        var uriBuilder = new UriBuilder(Uri);
 
         // Redact user/password or token from the URI string for logging
         if (uriBuilder.UserName is { Length: > 0 })
@@ -54,20 +69,6 @@ public NatsUri(string urlString, bool isSeed, string defaultScheme = DefaultSche
             }
         }
 
-        _redacted = IsWebSocket && Uri.AbsolutePath != "/" ? uriBuilder.Uri.ToString() : uriBuilder.Uri.ToString().Trim('/');
+        return IsWebSocket && Uri.AbsolutePath != "/" ? uriBuilder.Uri.ToString() : uriBuilder.Uri.ToString().Trim('/');
     }
-
-    public Uri Uri { get; init; }
-
-    public bool IsSeed { get; }
-
-    public bool IsTls { get; }
-
-    public bool IsWebSocket { get; }
-
-    public string Host => Uri.Host;
-
-    public int Port => Uri.Port;
-
-    public override string ToString() => _redacted;
 }

tests/NATS.Client.Core2.Tests/OnConnectingUriTest.cs

@@ -0,0 +1,32 @@
+using Microsoft.Extensions.Logging;
+using NATS.Client.Platform.Windows.Tests;
+using NATS.Client.TestUtilities;
+
+namespace NATS.Client.Core2.Tests;
+
+public class OnConnectingUriTest(ITestOutputHelper output)
+{
+    [Fact]
+    public async Task Logs_show_overridden_uri_when_OnConnectingAsync_changes_host_port()
+    {
+        await using var server = await NatsServerProcess.StartAsync();
+        var serverPort = server.Port;
+
+        var logger = new InMemoryTestLoggerFactory(LogLevel.Information, m => output.WriteLine($"LOG: {m.Message}"));
+
+        await using var nats = new NatsConnection(new NatsOpts
+        {
+            Url = "nats://original-host:4222",
+            LoggerFactory = logger,
+        });
+
+        nats.OnConnectingAsync = _ => new ValueTask<(string Host, int Port)>(("127.0.0.1", serverPort));
+
+        await nats.ConnectAsync();
+
+        var connectLog = logger.Logs.FirstOrDefault(m => m.Message.Contains("Connect to NATS using"));
+        Assert.NotNull(connectLog);
+        Assert.Contains($"127.0.0.1:{serverPort}", connectLog.Message);
+        Assert.DoesNotContain("original-host", connectLog.Message);
+    }
+}

tests/NATS.Client.CoreUnit.Tests/OptsUrlTests.cs

@@ -117,5 +117,25 @@ public void Keep_URL_wss_path_and_query_string()
         Assert.Equal("t,", opts.AuthOpts.Token);
     }
 
+    [Fact]
+    public void ToString_reflects_uri_changed_via_with_expression()
+    {
+        var original = new NatsUri("host1:4222", true);
+        Assert.Equal("nats://host1:4222", original.ToString());
+
+        var modified = original with { Uri = new UriBuilder(original.Uri) { Host = "host2", Port = 5222 }.Uri };
+        Assert.Equal("nats://host2:5222", modified.ToString());
+    }
+
+    [Fact]
+    public void ToString_reflects_uri_changed_via_with_expression_redacted()
+    {
+        var original = new NatsUri("u:p@host1:4222", true);
+        Assert.Equal("nats://u:***@host1:4222", original.ToString());
+
+        var modified = original with { Uri = new UriBuilder(original.Uri) { Host = "host2", Port = 5222 }.Uri };
+        Assert.Equal("nats://u:***@host2:5222", modified.ToString());
+    }
+
     private static string GetUrisAsRedactedString(NatsOpts opts) => string.Join(",", opts.GetSeedUris(true).Select(u => u.ToString()));
 }