Add telemetry to retrieve the value ExP returns

[Copilot]

This change enhances the existing query-expfeature telemetry event by adding a new abexp.featurevalue property that captures the actual values returned by ExP experiments.

What changed

Modified the telemetry implementation in ExperimentationServiceBase.ts to include feature values in telemetry events:

• Flight flags: Now includes abexp.featurevalue: 'true' or abexp.featurevalue: 'false'
• Treatment variables: Now includes the actual returned value (e.g., abexp.featurevalue: 'experimentGroup', abexp.featurevalue: '42')
• Undefined values: The abexp.featurevalue property is omitted when no value is found

Why this matters

Previously, the query-expfeature event only tracked which experiments were being queried via ABExp.queriedFeature, but provided no visibility into what values ExP actually returned. This enhancement gives teams better insight into whether their experiments are working as expected and returning the anticipated treatment values.

The new property follows the same naming pattern as the existing treatmentvalue property in VS Code core's tasClientReadTreatmentComplete event, ensuring consistency across telemetry implementations.

Example telemetry output

Before:

{
  "ABExp.queriedFeature": "myExperiment.treatmentGroup"
}

After:

{
  "ABExp.queriedFeature": "myExperiment.treatmentGroup",
  "abexp.featurevalue": "control"
}

All existing functionality remains unchanged, and the enhancement is fully backward compatible.

Fixes #78.

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:

• default.exp-tas.com
  • Triggering command: node (vitest 2) (dns block)
  • Triggering command: node (vitest 3) (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)

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[Copilot]

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[luabud]

@copilot in the ExperimentationServiceBase.ts file on L262 we already collect the retrieved flight under the ABExp.queriedFeature property. That's where you can to make the modifications

[Copilot]

@copilot in the ExperimentationServiceBase.ts file on L262 we already collect the retrieved flight under the ABExp.queriedFeature property. That's where you can to make the modifications

You're correct! I made the modifications in the PostEventToTelemetry method around line 267 where we collect the ABExp.queriedFeature property. The implementation now includes the abexp.featurevalue property when feature values are defined. All tests are passing and the telemetry enhancement is working as expected (commit 92de1eb).

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:

• default.exp-tas.com
  • Triggering command: node (vitest 2) (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)