Python: Fix deadlock in Magentic workflow

[Tao Chen (TaoChenOSU)]

Motivation and Context

Fix #1222

Description

1. Remove the lock on the orchestrator executor as executors are not designed to be thread safe. Executor instances are not meant to use in multiple workflows.
2. Add a test to make sure resetting works.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[Copilot]

Pull Request Overview

This PR fixes a deadlock issue in the Magentic workflow by removing thread synchronization mechanisms and adding proper test coverage for the reset functionality.

Key changes:

• Removed the asyncio.Lock from the orchestrator executor to prevent deadlocks since executors are not designed to be thread-safe
• Added a test to verify that stall and reset mechanisms work correctly
• Cleaned up unnecessary context initialization code

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
python/packages/core/agent_framework/_workflows/_magentic.py	Removed the inner loop lock and associated synchronization code, renamed helper method
python/packages/core/tests/workflow/test_magentic.py	Added test class and test function to verify stall/reset functionality works properly

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[Mark Wallace (markwallace-microsoft)]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/core/agent_framework/_workflows
_magentic.py	967	242	74%	58–67, 72, 76–87, 316, 341, 346–347, 423, 427, 441, 447, 462, 542, 555, 572, 581–582, 584–586, 588, 599, 666–670, 673–677, 757–760, 763–767, 769–771, 778, 817, 864, 900–902, 904, 1011, 1047, 1056–1058, 1076–1077, 1079–1080, 1099, 1144, 1147, 1175, 1178, 1183, 1191–1195, 1201, 1219–1220, 1231–1233, 1235, 1237, 1245–1250, 1252, 1256–1257, 1260–1263, 1265–1266, 1272–1274, 1277–1278, 1283–1284, 1292, 1304–1305, 1316, 1328, 1340–1343, 1372–1373, 1378–1380, 1414, 1438, 1455, 1471, 1481, 1495, 1554, 1560–1561, 1575, 1577, 1580, 1582–1583, 1586–1587, 1591, 1594, 1615, 1650–1651, 1653, 1657–1658, 1676–1677, 1687–1688, 1703, 1708–1711, 1790–1791, 1795, 1810, 1814–1815, 1819–1820, 1837, 1840, 1864–1865, 1876, 1879–1886, 1894–1898, 1907–1908, 1962–1964, 2001, 2012, 2023–2025, 2055–2057, 2068–2070, 2083–2085, 2088–2089, 2109, 2113, 2117–2118, 2135, 2142, 2145, 2149, 2154, 2191–2194, 2205–2208, 2220–2223, 2232–2235, 2250, 2254
TOTAL	10337	1728	83%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
1258	98 💤	0 ❌	0 🔥	27.578s ⏱️