Address graceful shutdown review feedback

Narrow .NET shutdown exception handling, avoid blocking Python's event loop while waiting for CLI process exit, clear external force-stop process references, and apply Java formatting.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: stephentoub

dotnet/src/Client.cs

@@ -439,7 +439,11 @@ private async Task CleanupConnectionAsync(Connection ctx, List<Exception>? error
                     "CopilotClient.StopAsync runtime shutdown complete. Elapsed={Elapsed}",
                     runtimeShutdownTimestamp);
             }
-            catch (Exception ex)
+            catch (Exception ex) when (ex is OperationCanceledException
+                or InvalidOperationException
+                or ObjectDisposedException
+                or IOException
+                or SocketException)
             {
                 LoggingHelpers.LogTiming(_logger, LogLevel.Debug, ex,
                     "CopilotClient.StopAsync runtime shutdown failed. Elapsed={Elapsed}",

java/src/main/java/com/github/copilot/CopilotClient.java

@@ -381,7 +381,8 @@ public CompletableFuture<Void> forceStop() {
         // executor, so a plain whenComplete(...) here could land the awaitTermination
         // call on one of the very threads it is waiting to drain, forcing the full
         // AUTOCLOSEABLE_TIMEOUT_SECONDS timeout followed by shutdownNow().
-        return cleanupConnection(false).whenCompleteAsync((ignored, error) -> shutdownOwnedExecutor(), SHUTDOWN_DISPATCHER);
+        return cleanupConnection(false).whenCompleteAsync((ignored, error) -> shutdownOwnedExecutor(),
+                SHUTDOWN_DISPATCHER);
     }
 
     private CompletableFuture<Void> cleanupConnection(boolean gracefulRuntimeShutdown) {

java/src/test/java/com/github/copilot/CopilotClientTest.java

@@ -46,7 +46,8 @@ static void setup() {
     void testStopRequestsRuntimeShutdownForOwnedProcess() throws Exception {
         var client = new CopilotClient(new CopilotClientOptions().setAutoStart(false));
         var rpc = mock(JsonRpcClient.class);
-        when(rpc.invoke(eq("runtime.shutdown"), any(), eq(Void.class))).thenReturn(CompletableFuture.completedFuture(null));
+        when(rpc.invoke(eq("runtime.shutdown"), any(), eq(Void.class)))
+                .thenReturn(CompletableFuture.completedFuture(null));
         var process = mock(Process.class);
         when(process.isAlive()).thenReturn(true);
         when(process.waitFor(anyLong(), any(TimeUnit.class))).thenReturn(true);

python/copilot/client.py

@@ -1528,15 +1528,24 @@ async def stop(self) -> None:
             if is_running:
                 if runtime_shutdown_completed:
                     try:
-                        self._cli_process.wait(timeout=_RUNTIME_SHUTDOWN_TIMEOUT_SECONDS)
+                        await asyncio.to_thread(
+                            self._cli_process.wait,
+                            timeout=_RUNTIME_SHUTDOWN_TIMEOUT_SECONDS,
+                        )
                     except subprocess.TimeoutExpired:
                         self._cli_process.terminate()
                         try:
-                            self._cli_process.wait(timeout=_CLI_PROCESS_EXIT_TIMEOUT_SECONDS)
+                            await asyncio.to_thread(
+                                self._cli_process.wait,
+                                timeout=_CLI_PROCESS_EXIT_TIMEOUT_SECONDS,
+                            )
                         except subprocess.TimeoutExpired:
                             self._cli_process.kill()
                             try:
-                                self._cli_process.wait(timeout=_CLI_PROCESS_EXIT_TIMEOUT_SECONDS)
+                                await asyncio.to_thread(
+                                    self._cli_process.wait,
+                                    timeout=_CLI_PROCESS_EXIT_TIMEOUT_SECONDS,
+                                )
                             except subprocess.TimeoutExpired as e:
                                 errors.append(
                                     StopError(
@@ -1549,17 +1558,22 @@ async def stop(self) -> None:
                 else:
                     self._cli_process.terminate()
                     try:
-                        self._cli_process.wait(timeout=_CLI_PROCESS_EXIT_TIMEOUT_SECONDS)
+                        await asyncio.to_thread(
+                            self._cli_process.wait,
+                            timeout=_CLI_PROCESS_EXIT_TIMEOUT_SECONDS,
+                        )
                     except subprocess.TimeoutExpired:
                         self._cli_process.kill()
                         try:
-                            self._cli_process.wait(timeout=_CLI_PROCESS_EXIT_TIMEOUT_SECONDS)
+                            await asyncio.to_thread(
+                                self._cli_process.wait,
+                                timeout=_CLI_PROCESS_EXIT_TIMEOUT_SECONDS,
+                            )
                         except subprocess.TimeoutExpired as e:
                             errors.append(
                                 StopError(
                                     message=(
-                                        "Timed out waiting for CLI process to exit after kill: "
-                                        f"{e}"
+                                        f"Timed out waiting for CLI process to exit after kill: {e}"
                                     )
                                 )
                             )
@@ -1602,6 +1616,8 @@ async def force_stop(self) -> None:
                 if self._is_external_server:
                     if self._process is not None:
                         self._process.terminate()  # closes the TCP socket
+                    self._process = None
+                    self._cli_process = None
                 else:
                     if self._process is not None and self._process is not self._cli_process:
                         self._process.terminate()

python/test_client.py

@@ -79,6 +79,20 @@ async def shutdown(self):
 
         assert calls == []
 
+    @pytest.mark.asyncio
+    async def test_force_stop_external_server_clears_process_references(self):
+        process = Mock()
+        client = CopilotClient(connection=RuntimeConnection.for_uri("localhost:1234"))
+        client._is_external_server = True
+        client._process = process
+        client._cli_process = process
+
+        await client.force_stop()
+
+        process.terminate.assert_called_once()
+        assert client._process is None
+        assert client._cli_process is None
+
 
 class TestPermissionHandlerOptional:
     @pytest.mark.asyncio