Enhance Windows Compatibility with Event Loop Policy and Path Resolution (#3986)

Co-authored-by: Suchintan <suchintan@users.noreply.github.com>
Co-authored-by: Shuchang Zheng <wintonzheng0325@gmail.com>
Co-authored-by: Stanislav Novosad <stas@skyvern.com>

skyvern/utils/__init__.py

@@ -1,3 +1,4 @@
+import asyncio
 import platform
 import subprocess
 from pathlib import Path
@@ -8,6 +9,28 @@ from alembic.config import Config
 from skyvern.constants import REPO_ROOT_DIR
 
 
+def setup_windows_event_loop_policy() -> None:
+    """
+    Ensure the Windows event loop policy supports subprocesses (required by Playwright).
+
+    Explicitly setting the Proactor event loop policy prevents third-party packages or older
+    Python defaults from forcing the Selector policy, which does not implement subprocess
+    transports and causes runtime failures when Playwright tries to launch a browser.
+    """
+    if platform.system() != "Windows":
+        return
+
+    windows_policy_cls = getattr(asyncio, "WindowsProactorEventLoopPolicy", None)
+    if windows_policy_cls is None:
+        return
+
+    current_policy = asyncio.get_event_loop_policy()
+    if isinstance(current_policy, windows_policy_cls):
+        return
+
+    asyncio.set_event_loop_policy(windows_policy_cls())
+
+
 def migrate_db() -> None:
     alembic_cfg = Config()
     path = f"{REPO_ROOT_DIR}/alembic"