fix(node): MESHBAY_NODE_EVENT_LOOP=proactor to opt out of the selector loop

Whether aiortc actually hangs on the ProactorEventLoop for a live peer (as
opposed to the same-process loopback the tests use) is still open. This lets
a Windows node keep the default loop for that comparison — and, if Proactor
turns out fine, keep subprocess ffmpeg working without a code change.

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

1 files changed, 11 insertions, 5 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/platform.py b/packages/meshbay-node/src/meshbay_node/platform.py
index 80aa6ae..2eab9e1 100644
--- a/packages/meshbay-node/src/meshbay_node/platform.py
+++ b/packages/meshbay-node/src/meshbay_node/platform.py
@@ -29,17 +29,23 @@ def force_utf8_stdio() -> None:
 
 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.
+    On Windows, select the SelectorEventLoop: aiortc's ICE stack does not
+    complete a loopback DataChannel handshake on the default ProactorEventLoop.
 
     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.
+
+    Whether the hang is real for a live peer (vs. the same-process loopback in
+    the tests) is still being established: set MESHBAY_NODE_EVENT_LOOP=proactor
+    to keep the default loop and check.
     """
-    if sys.platform == "win32":
-        asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
+    if sys.platform != "win32":
+        return
+    if os.environ.get("MESHBAY_NODE_EVENT_LOOP", "").lower() == "proactor":
+        return
+    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
 
 
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