.NET: Added support for polymorphic type as workflow output#4485
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.NET: Added support for polymorphic type as workflow output#4485
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Pull request overview
Adds support for workflow outputs to be validated polymorphically so executors can return derived instances when their declared workflow output type is a base class (fixing issue #4134).
Changes:
- Update executor output validation to accept derived types for declared yield/output types.
- Add unit tests covering derived, multi-level derived, exact-type, and unrelated-type output behaviors.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| dotnet/src/Microsoft.Agents.AI.Workflows/Executor.cs | Adjusts CanOutput logic to validate outputs polymorphically (base-class inheritance). |
| dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/PolymorphicOutputTests.cs | Adds regression coverage for derived outputs and ensures unrelated outputs still fail. |
lokitoth
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Mar 9, 2026
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Mar 9, 2026
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Mar 9, 2026
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Mar 9, 2026
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Mar 11, 2026
…t#4485) * Added support for polymorphic type as workflow output * Update Linq expression to avoid unnecessary allocations. * Added caching as per PR comment
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Description
Added support for polymorphic type as workflow output and enable executors to return instance of derived class which inherits from the base class.
Fixes #4134
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