Handle RejectedExecutionException in all async submission sites

Agent-Logs-Url: https://github.com/github/copilot-sdk-java/sessions/63b9b09f-f1f4-44d3-8e34-ad01e355cc6a

Co-authored-by: edburns <75821+edburns@users.noreply.github.com>

Author: Copilot

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

@@ -14,6 +14,7 @@
 import java.util.concurrent.CompletionException;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -152,9 +153,13 @@ private CompletableFuture<Connection> startCore() {
         LOG.fine("Starting Copilot client");
 
         Executor exec = options.getExecutor();
-        return exec != null
-                ? CompletableFuture.supplyAsync(this::startCoreBody, exec)
-                : CompletableFuture.supplyAsync(this::startCoreBody);
+        try {
+            return exec != null
+                    ? CompletableFuture.supplyAsync(this::startCoreBody, exec)
+                    : CompletableFuture.supplyAsync(this::startCoreBody);
+        } catch (RejectedExecutionException e) {
+            return CompletableFuture.failedFuture(e);
+        }
     }
 
     private Connection startCoreBody() {
@@ -244,8 +249,17 @@ public CompletableFuture<Void> stop() {
                     LOG.log(Level.WARNING, "Error closing session " + session.getSessionId(), e);
                 }
             };
-            closeFutures.add(
-                    exec != null ? CompletableFuture.runAsync(closeTask, exec) : CompletableFuture.runAsync(closeTask));
+            CompletableFuture<Void> future;
+            try {
+                future = exec != null
+                        ? CompletableFuture.runAsync(closeTask, exec)
+                        : CompletableFuture.runAsync(closeTask);
+            } catch (RejectedExecutionException e) {
+                LOG.log(Level.WARNING, "Executor rejected session close task; closing inline", e);
+                closeTask.run();
+                future = CompletableFuture.completedFuture(null);
+            }
+            closeFutures.add(future);
         }
         sessions.clear();
 

src/main/java/com/github/copilot/sdk/CopilotSession.java

@@ -729,10 +729,15 @@ private void executeToolAndRespondAsync(String requestId, String toolName, Strin
                 }
             }
         };
-        if (executor != null) {
-            CompletableFuture.runAsync(task, executor);
-        } else {
-            CompletableFuture.runAsync(task);
+        try {
+            if (executor != null) {
+                CompletableFuture.runAsync(task, executor);
+            } else {
+                CompletableFuture.runAsync(task);
+            }
+        } catch (RejectedExecutionException e) {
+            LOG.log(Level.WARNING, "Executor rejected tool task for requestId=" + requestId + "; running inline", e);
+            task.run();
         }
     }
 
@@ -782,10 +787,16 @@ private void executePermissionAndRespondAsync(String requestId, PermissionReques
                 }
             }
         };
-        if (executor != null) {
-            CompletableFuture.runAsync(task, executor);
-        } else {
-            CompletableFuture.runAsync(task);
+        try {
+            if (executor != null) {
+                CompletableFuture.runAsync(task, executor);
+            } else {
+                CompletableFuture.runAsync(task);
+            }
+        } catch (RejectedExecutionException e) {
+            LOG.log(Level.WARNING, "Executor rejected permission task for requestId=" + requestId + "; running inline",
+                    e);
+            task.run();
         }
     }
 

src/main/java/com/github/copilot/sdk/RpcHandlerDispatcher.java

@@ -10,6 +10,7 @@
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionException;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -367,10 +368,15 @@ private void handleSystemMessageTransform(JsonRpcClient rpc, String requestId, J
     }
 
     private void runAsync(Runnable task) {
-        if (executor != null) {
-            CompletableFuture.runAsync(task, executor);
-        } else {
-            CompletableFuture.runAsync(task);
+        try {
+            if (executor != null) {
+                CompletableFuture.runAsync(task, executor);
+            } else {
+                CompletableFuture.runAsync(task);
+            }
+        } catch (RejectedExecutionException e) {
+            LOG.log(Level.WARNING, "Executor rejected handler task; running inline", e);
+            task.run();
         }
     }
 }