validate that providers are > 0 to provide clear error when using Diagnostics Client...

validate that providers are > 0 otherwise START Failed 0x80131384 get…s
thrown and it's not clear what the issue is.

The current behavior when an empty list of providers is provided is to
throw START Failed 0x80131384 (BadEncoding) and that doesn't make it
very clear about what the issue is. This PR proposes validating the
number of providers so developers know that they should be providing 1
provider at least.

Before:
<img width="677" alt="image"
src="https://github.com/dotnet/diagnostics/assets/30415120/0dfe0963-97ae-4f1a-8ce5-46b992b55428">

After:
<img width="679" alt="image"
src="https://github.com/dotnet/diagnostics/assets/30415120/f171687b-eaa5-4bbb-945c-16a43f4b97b0">

Co-authored-by: Daniel Espinosa <luespino@microsoft.com>

diff --git a/src/Microsoft.Diagnostics.NETCore.Client/DiagnosticsClient/EventPipeSessionConfiguration.cs b/src/Microsoft.Diagnostics.NETCore.Client/DiagnosticsClient/EventPipeSessionConfiguration.cs
index d4884b6500b90d9ba2c115acd19a39a0e1d5257b..8f3f3b2b7f462d5867b83f4132bfdfb0913c8058 100644 (file)
--- a/src/Microsoft.Diagnostics.NETCore.Client/DiagnosticsClient/EventPipeSessionConfiguration.cs
+++ b/src/Microsoft.Diagnostics.NETCore.Client/DiagnosticsClient/EventPipeSessionConfiguration.cs
@@ -53,11 +53,16 @@ namespace Microsoft.Diagnostics.NETCore.Client
                 throw new ArgumentNullException(nameof(providers));
             };
 
+            _providers = new List<EventPipeProvider>(providers);
+            if (_providers.Count == 0)
+            {
+                throw new ArgumentException("At least one provider must be specified.");
+            };
+
             CircularBufferSizeInMB = circularBufferSizeMB;
             Format = format;
             RequestRundown = requestRundown;
             RequestStackwalk = requestStackwalk;
-            _providers = new List<EventPipeProvider>(providers);
         }
 
         /// <summary>