Remove explicit ActivityStatusCode.Ok setting to comply with OpenTelemetry specification

[Copilot]

Problem

Orleans was explicitly setting ActivityStatusCode.Ok after successful grain calls, which violates the OpenTelemetry specification guidance. According to OTEP 0136:

OK represents a span which has been explicitly marked as being free of errors, and should not be counted against an error budget. Note that only end users should set this status. Instead, instrumentation should leave the status as UNSET for operations that do not generate an error.

The specification defines three status codes:

• UNSET - the default status code (instrumentation should use this for successful operations)
• ERROR - represents all error types
• OK - should only be set explicitly by end users, not instrumentation libraries

Changes

Removed the explicit setting of ActivityStatusCode.Ok in ActivityPropagationGrainCallFilter.cs after successful grain call completions. The activity status now remains as UNSET (the default) for successful operations.

Before:

try
{
    await context.Invoke();
    if (activity is not null && activity.IsAllDataRequested)
    {
        activity.SetStatus(ActivityStatusCode.Ok);  // ❌ Violates spec
    }
}

After:

try
{
    await context.Invoke();
    // Status remains UNSET (default) for successful operations ✓
}

Error handling remains unchanged - exceptions still correctly set ActivityStatusCode.Error with appropriate exception tags.

Impact

• ✅ Complies with OpenTelemetry specification
• ✅ No breaking changes to functionality
• ✅ Activity propagation, tracing, and baggage handling unchanged
• ✅ Error handling unchanged

Fixes #9078

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• 0t3vsblobprodcus362.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• 96bvsblobprodcus338.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• cflvsblobprodcus383.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• ckzvsblobprodcus347.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• dnceng.pkgs.visualstudio.com
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• frdvsblobprodcus327.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• imzvsblobprodcus368.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• jrqvsblobprodcus343.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• kh4vsblobprodcus325.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• lylvsblobprodcus31.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• m6xvsblobprodcus342.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• pdfvsblobprodcus380.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• rcxvsblobprodcus328.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)
• yluvsblobprodcus367.vsblob.vsassets.io
  • Triggering command: dotnet build src/Orleans.Core/Orleans.Core.csproj --configuration Debug -v minimal (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Wrong OpenTelemtry traces status</issue_title>
<issue_description>Hello.
Please do not explicitly set the OK status, as it is not recommended by the OpenTelemetry developers.

orleans/src/Orleans.Core/Diagnostics/ActivityPropagationGrainCallFilter.cs

Line 54 in 986da59

activity.SetStatus(ActivityStatusCode.Ok);

</issue_description>

<agent_instructions>Fix the OpenTelemetry implementation in Orleans so that it follows the official guidance by not explicitly setting the Ok status code</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@ReubenBond Source: https://github.com/open-telemetry/oteps/blob/main/text/trace/0136-error_flagging.md > Status Codes Currently, OpenTelemetry does not have a use case for differentiating between different types of errors. However, this use case may appear in the future. For now, we would like to reduce the number of status codes, and then add them back in as the need becomes clear. We would also like to differentiate between status codes which have not been set, and an explicit OK status set by an end user. > > * UNSET is the default status code. > * ERROR represents all error types. > * OK represents a span which has been explicitly marked as being free of errors, and should not be counted against an error budget. Note that only end users should set this status. Instead, instrumentation should leave the status as UNSET for operations that do not generate an error.

Fixes #9694

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Microsoft Reviewers: Open in CodeFlow