Python: fix declarative workflow DevUI sample and JoinExecutor Messag…

[amit12cool]

Motivation & Context

The workflow_declarative DevUI sample under python/samples/02-agents/devui/workflow_declarative/ was broken when run via the DevUI chat interface. Entering any age value always returned the "child" category. Four bugs caused this:

1. workflow.yaml used =inputs.age — this only works when the workflow is invoked with a structured dict input (e.g. {"age": 25}). The DevUI sends user messages as chat text, which populates System.LastMessage.Text, not Inputs.age. As a result =inputs.age was always Blank (treated as 0 by PowerFx), causing 0 < 13 to always evaluate True → "child" for any input.

2. workflow.yaml used turn.* namespace — turn is a .NET/Bot Framework convention. In the Python runtime, per-turn variables belong in the Local.* namespace.

3. workflow.yaml used workflow.outputs.category (lowercase w) — the Python state engine is case-sensitive; the correct namespace is Workflow.Outputs.*.

4. JoinExecutor did not handle a single Message trigger — when a Message (not list[Message]) was passed as the trigger, _ensure_state_initialized could not extract the user text into System.LastMessage.Text, compounding issue 1.

Description & Review Guide

• What are the major changes?

  • workflow.yaml: replace =inputs.age with =Int(System.LastMessage.Text); replace turn.* with Local.*; fix workflow.outputs.category → Workflow.Outputs.category; remove the now-unused inputs: schema block
  • workflow.py: add logging.basicConfig so DevUI startup output is readable
  • _executors_control_flow.py (JoinExecutor): normalize a single Message trigger to list[Message] before passing to _ensure_state_initialized, so user text is correctly surfaced in System.LastMessage.Text

• What is the impact of these changes?
  The DevUI sample now works correctly end-to-end. JoinExecutor also correctly handles single-message triggers in all workflows that use it.

• What do you want reviewers to focus on?
  The JoinExecutor change in _executors_control_flow.py and whether any other executors have the same single-Message gap.

Related Issue

Fixes #

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.

[Copilot]

Pull request overview

Fixes the Python declarative-workflow DevUI sample so it correctly categorizes users based on age entered via the chat UI (using System.LastMessage.Text / Local.* / Workflow.Outputs.*), and updates the declarative workflow runtime so JoinExecutor properly initializes state when triggered with a single Message.

Changes:

• Updated the DevUI sample workflow.yaml to read age from chat text, use Local.* variables, and correctly write outputs to Workflow.Outputs.*.
• Improved DevUI sample startup logging readability by configuring logging.basicConfig(...).
• Updated JoinExecutor to normalize a single Message trigger to list[Message] before state initialization.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
python/samples/02-agents/devui/workflow_declarative/workflow.yaml	Fixes expression namespaces and input source so DevUI chat input drives correct branching and output state.
python/samples/02-agents/devui/workflow_declarative/workflow.py	Adds simple logging configuration to make DevUI startup output easier to read.
python/packages/declarative/agent_framework_declarative/_workflows/_executors_control_flow.py	Ensures JoinExecutor correctly initializes state for single-Message triggers (DevUI-style).

[moonbox3]

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