[WhaleTech (ryo-whaletech)]

Motivation & Context

Abandoning a graph Workflow.run(..., stream=True) after a visible event can finalize the generator from another Python Context while its workflow.run span is still attached, logging Failed to detach context. #7798 established the corresponding lifecycle constraint for functional workflows and identified graph workflows as the remaining follow-up.

Description & Review Guide

• What are the major changes? Start the graph run span unattached, activate it around initial execution and each non-yielding runner pull, and end it in finally. Add abandonment cleanup coverage and assert the outer-to-workflow-to-executor span chain.
• What is the impact of these changes? A caller can stop consuming a graph stream without an OTel context-detach error; graph events, results, errors, and executor span parenting remain intact.
• What do you want reviewers to focus on? The activation boundary around each runner pull and the preservation of executor processing span parents without holding an OTel token across a caller-visible yield.

Related Issue

Fixes #8397

Contribution Checklist

• The code builds clean without any errors or warnings
• All unit tests pass, and I have added new tests where possible
• The PR follows the Contribution Guidelines
• This PR is linked to an issue and there is no other open PR for this issue (see Related Issue above).
• This is not a breaking change. If it is a breaking change, add the breaking change label (or add "[BREAKING]" to the title prefix, before or after any language prefix) — a workflow keeps the label and title prefix in sync automatically.

[Copilot]

🟢 Approval recommended

No unresolved blocking issues were identified.

Pull request overview

Updates graph workflow tracing to prevent OpenTelemetry context leaks when streams are abandoned while preserving span parenting.

Changes:

• Scopes workflow span activation around execution and runner pulls.
• Adds abandoned-stream cleanup tests.
• Verifies span hierarchy and caller context preservation.

File summaries

File	Summary
python/packages/core/tests/workflow/test_workflow.py	Tests abandoned-stream cleanup.
python/packages/core/tests/workflow/test_workflow_observability.py	Verifies span hierarchy and context preservation.
python/packages/core/agent_framework/_workflows/_workflow.py	Updates graph workflow span lifecycle.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 0
• Review effort level: Lite (auto)

Note

Copilot is running an experiment and ran this review at Lite.

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[Eduard van Valkenburg (eavanvalkenburg)]

I reviewed the complete diff and found no actionable code issues. Since this PR is still a draft, I’m leaving this as a comment rather than an approval; please mark it ready when you want the approval-gated checks and final review.