ActivityTraceFlags is not reflected in Activity Id when updated after activity start()

[vishweshbankwar]

Description

ActivityTraceFlags can be updated after activity is started. However, doing so does not update the activity Id.

Reproduction Steps

var activity = new Activity("Test");
activity.Start();
Console.WriteLine("ActivityId Before TraceFlags are set: " + activity.Id);
Console.WriteLine("ActivityTraceFlags Before: " + activity.ActivityTraceFlags);
activity.ActivityTraceFlags |= ActivityTraceFlags.Recorded;
Console.WriteLine("ActivityId After TraceFlags are set: " + activity.Id);
Console.WriteLine("ActivityTraceFlags After: " + activity.ActivityTraceFlags);

---- sample output ----
ActivityId Before TraceFlags are set: 00-b33ee4ebf1fa3d81e0ab30363fe291e2-40f3aace946db1d2-00
ActivityTraceFlags Before: None
ActivityId After TraceFlags are set: 00-b33ee4ebf1fa3d81e0ab30363fe291e2-40f3aace946db1d2-00
ActivityTraceFlags After: Recorded

Expected behavior

Updated ActivityTraceFlags is reflected in Activity.Id

Actual behavior

Updated ActivityTraceFlags is not reflected in Activity.Id

Regression?

No

Known Workarounds

No response

Configuration

No response

Other information

No response

[ghost]

Tagging subscribers to this area: @tarekgh
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

ActivityTraceFlags can be updated after activity is started. However, doing so does not update the activity Id.

Reproduction Steps

var activity = new Activity("Test");
activity.Start();
Console.WriteLine("ActivityId Before TraceFlags are set: " + activity.Id);
Console.WriteLine("ActivityTraceFlags Before: " + activity.ActivityTraceFlags);
activity.ActivityTraceFlags |= ActivityTraceFlags.Recorded;
Console.WriteLine("ActivityId After TraceFlags are set: " + activity.Id);
Console.WriteLine("ActivityTraceFlags After: " + activity.ActivityTraceFlags);

---- sample output ----
ActivityId Before TraceFlags are set: 00-b33ee4ebf1fa3d81e0ab30363fe291e2-40f3aace946db1d2-00
ActivityTraceFlags Before: None
ActivityId After TraceFlags are set: 00-b33ee4ebf1fa3d81e0ab30363fe291e2-40f3aace946db1d2-00
ActivityTraceFlags After: Recorded

Expected behavior

Updated ActivityTraceFlags is reflected in Activity.Id

Actual behavior

Updated ActivityTraceFlags is not reflected in Activity.Id

Regression?

No

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	vishweshbankwar
Assignees:	-
Labels:	untriaged, area-System.Diagnostics.Activity
Milestone:	-

[vishweshbankwar]

@cijothomas @tarekgh - Adding it here for tracking.

[cijothomas]

For now, there are workarounds which needs to tried first. This issue requires no action, until the workarounds are tried in OpenTelemetry/ApplicationInsights.