Fix Windows CI logging warnings during interpreter shutdown

Guard logging calls in SubprocessTransport.close() and WorkerPool.close()
with a _stderr_open() check to prevent ValueError tracebacks when stderr
is already closed during Python interpreter shutdown on Windows.

Bump version to 0.1.13.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: rustyconover

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "vgi-rpc"
-version = "0.1.12"
+version = "0.1.13"
 description = "Vector Gateway Interface - RPC framework based on Apache Arrow"
 readme = "README.md"
 requires-python = ">=3.13"

vgi_rpc/pool.py

@@ -27,7 +27,7 @@
 from vgi_rpc.external import ExternalLocationConfig
 from vgi_rpc.log import Message
 from vgi_rpc.rpc._client import RpcConnection, StreamSession
-from vgi_rpc.rpc._transport import StderrMode, SubprocessTransport
+from vgi_rpc.rpc._transport import StderrMode, SubprocessTransport, _stderr_open
 from vgi_rpc.shm import ShmSegment
 from vgi_rpc.utils import IpcValidation
 
@@ -325,9 +325,10 @@ def close(self) -> None:
                 dq.clear()
             self._idle.clear()
 
-        if active > 0:
+        if active > 0 and _stderr_open():
             _logger.warning("WorkerPool closing with %d active connections", active)
-        _logger.info("WorkerPool closed: terminated %d idle workers", len(all_idle))
+        if _stderr_open():
+            _logger.info("WorkerPool closed: terminated %d idle workers", len(all_idle))
 
         for transport in all_idle:
             self._discards += 1

vgi_rpc/rpc/_transport.py

@@ -24,6 +24,14 @@
     from vgi_rpc.rpc._server import RpcServer
 
 
+def _stderr_open() -> bool:
+    """Return True if stderr is still writable (guards against Windows shutdown)."""
+    try:
+        return sys.stderr is not None and not sys.stderr.closed
+    except ValueError:
+        return False
+
+
 # ---------------------------------------------------------------------------
 # RpcTransport protocol
 # ---------------------------------------------------------------------------
@@ -265,11 +273,8 @@ def close(self) -> None:
         """Close stdin (sends EOF), wait for exit, close stdout."""
         if self._closed:
             return
-        try:
-            if wire_transport_logger.isEnabledFor(logging.DEBUG):
-                wire_transport_logger.debug("SubprocessTransport closing: pid=%d", self._proc.pid)
-        except ValueError:
-            pass  # stderr closed during interpreter shutdown (Windows)
+        if _stderr_open() and wire_transport_logger.isEnabledFor(logging.DEBUG):
+            wire_transport_logger.debug("SubprocessTransport closing: pid=%d", self._proc.pid)
         self._closed = True
         if self._proc.stdin:
             self._proc.stdin.close()
@@ -281,15 +286,12 @@ def close(self) -> None:
         if self._stderr_thread is not None:
             self._stderr_thread.join(timeout=5)
         self._reader.close()
-        try:
-            if wire_transport_logger.isEnabledFor(logging.DEBUG):
-                wire_transport_logger.debug(
-                    "SubprocessTransport closed: pid=%d, exit_code=%s",
-                    self._proc.pid,
-                    self._proc.returncode,
-                )
-        except ValueError:
-            pass  # stderr closed during interpreter shutdown (Windows)
+        if _stderr_open() and wire_transport_logger.isEnabledFor(logging.DEBUG):
+            wire_transport_logger.debug(
+                "SubprocessTransport closed: pid=%d, exit_code=%s",
+                self._proc.pid,
+                self._proc.returncode,
+            )
 
 
 def serve_stdio(server: RpcServer) -> None: