fix(node): select the Windows-compatible event loop before asyncio.run

aiortc's ICE stack does not run on Windows' default ProactorEventLoop -- a
DataChannel handshake never completes. `platform.use_compatible_event_loop()`
switches to the SelectorEventLoop on win32, called at the top of `main()`
before `asyncio.run()`. No-op off Windows.

Known cost, for when the node runs on Windows: the SelectorEventLoop cannot
spawn subprocesses, so ffmpeg streaming (asyncio.create_subprocess_exec in
webrtc_server.py) needs a thread-based runner there. Tracked separately.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

2 files changed, 22 insertions, 0 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/daemon.py b/packages/meshbay-node/src/meshbay_node/daemon.py
index 47241cd..d616b0c 100644
--- a/packages/meshbay-node/src/meshbay_node/daemon.py
+++ b/packages/meshbay-node/src/meshbay_node/daemon.py
@@ -1634,6 +1634,9 @@ def _systemctl_user(verb: str, unit: str, *, not_running_hint: str,
 def main() -> None:
     import argparse
 
+    from meshbay_node.platform import use_compatible_event_loop
+    use_compatible_event_loop()
+
     parser = argparse.ArgumentParser(description="MeshBay Node daemon")
     parser.add_argument("command", nargs="?",
                         choices=["init", "reset", "status", "gek-init",
diff --git a/packages/meshbay-node/src/meshbay_node/platform.py b/packages/meshbay-node/src/meshbay_node/platform.py
index bc48169..4bd8e35 100644
--- a/packages/meshbay-node/src/meshbay_node/platform.py
+++ b/packages/meshbay-node/src/meshbay_node/platform.py
@@ -1,10 +1,29 @@
 """Platform-specific paths and tool resolution for meshbay-node."""
 
+import asyncio
 import os
 import shutil
 import sys
 from pathlib import Path
 
+# ── Event loop ───────────────────────────────────────────────────────────────
+
+
+def use_compatible_event_loop() -> None:
+    """
+    aiortc's ICE stack (aioice) does not run on Windows' default
+    ProactorEventLoop — a DataChannel handshake never completes and the
+    connection hangs. Select the SelectorEventLoop before the loop is created.
+
+    Cost: SelectorEventLoop cannot spawn subprocesses on Windows, so ffmpeg
+    streaming (asyncio.create_subprocess_exec in webrtc_server.py) does not work
+    under it. The video path needs a thread-based runner on Windows — tracked
+    for the port. No effect off Windows.
+    """
+    if sys.platform == "win32":
+        asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
+
+
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