Avoid stream ID and client result ID collisions (#46591)

Co-authored-by: Brennan Conroy <brecon@microsoft.com>

src/SignalR/server/Core/src/DefaultHubLifetimeManager.cs

@@ -3,7 +3,6 @@
 
 using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
-using System.Globalization;
 using System.Linq;
 using Microsoft.AspNetCore.SignalR.Internal;
 using Microsoft.AspNetCore.SignalR.Protocol;
@@ -340,7 +339,10 @@ public override async Task<T> InvokeConnectionAsync<T>(string connectionId, stri
             throw new IOException($"Connection '{connectionId}' does not exist.");
         }
 
-        var invocationId = Interlocked.Increment(ref _lastInvocationId).ToString(NumberFormatInfo.InvariantInfo);
+        var id = Interlocked.Increment(ref _lastInvocationId);
+        // prefix the client result ID with 's' for server, so that it won't conflict with other CompletionMessage's from the client
+        // e.g. Stream IDs when completing
+        var invocationId = $"s{id}";
 
         using var _ = CancellationTokenUtils.CreateLinkedToken(cancellationToken,
             connection.ConnectionAborted, out var linkedToken);

src/SignalR/server/SignalR/test/HubConnectionHandlerTests.ClientResult.cs

@@ -453,11 +453,17 @@ public async Task ClientResultInUploadStreamingMethodWorks()
             {
                 var connectionHandlerTask = await client.ConnectAsync(connectionHandler).DefaultTimeout();
 
-                var invocationId = await client.BeginUploadStreamAsync("1", nameof(MethodHub.GetClientResultWithStream), new[] { "id" }, Array.Empty<object>()).DefaultTimeout();
+                // Regression test: Use 1 as the stream ID as this is the first ID the server would use for invocation IDs it generates
+                // We want to make sure the client result completion doesn't accidentally complete the stream
+                var streamId = "1";
+                var invocationId = await client.BeginUploadStreamAsync("1", nameof(MethodHub.GetClientResultWithStream), new[] { streamId }, Array.Empty<object>()).DefaultTimeout();
 
                 // Hub asks client for a result, this is an invocation message with an ID
                 var invocationMessage = Assert.IsType<InvocationMessage>(await client.ReadAsync().DefaultTimeout());
                 Assert.NotNull(invocationMessage.InvocationId);
+                // This check isn't really needed except we want to make sure the regression test mentioned above is still testing the expected scenario
+                Assert.Equal("s1", invocationMessage.InvocationId);
+
                 var res = 4 + ((long)invocationMessage.Arguments[0]);
                 await client.SendHubMessageAsync(CompletionMessage.WithResult(invocationMessage.InvocationId, res)).DefaultTimeout();