On branch copilot-pr-20 Address "5. **NO_RESULT permission handling — silent no-op** — MEDIUM RISK"

modified:   .gitignore
	modified:   src/main/java/com/github/copilot/sdk/RpcHandlerDispatcher.java
	modified:   src/main/java/com/github/copilot/sdk/json/PermissionRequestResultKind.java
	modified:   src/test/java/com/github/copilot/sdk/RpcHandlerDispatcherTest.java
	modified:   src/test/java/com/github/copilot/sdk/SessionHandlerTest.java

Author: edburns

.gitignore

@@ -7,3 +7,4 @@ blog-copilotsdk/
 smoke-test
 *job-logs.txt
 temporary-prompts/
+changebundle.txt*

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

@@ -194,9 +194,11 @@ private void handlePermissionRequest(JsonRpcClient rpc, String requestId, JsonNo
                 session.handlePermissionRequest(permissionRequest).thenAccept(result -> {
                     try {
                         if (PermissionRequestResultKind.NO_RESULT.getValue().equalsIgnoreCase(result.getKind())) {
-                            // Handler explicitly abstains — do not send a response,
-                            // allowing another client to handle the request.
-                            return;
+                            // Protocol v2 does not support NO_RESULT — the server
+                            // expects exactly one response per request, so abstaining
+                            // would leave it hanging.
+                            throw new IllegalStateException(
+                                    "Permission handlers cannot return 'no-result' when connected to a protocol v2 server.");
                         }
                         rpc.sendResponse(Long.parseLong(requestId), Map.of("result", result));
                     } catch (IOException e) {

src/main/java/com/github/copilot/sdk/json/PermissionRequestResultKind.java

@@ -58,6 +58,11 @@ public final class PermissionRequestResultKind {
      * cannot or chooses not to handle a given permission request, it can return
      * {@code NO_RESULT} to leave the request unanswered, allowing another client to
      * handle it.
+     * <p>
+     * <strong>Warning:</strong> This kind is only valid with protocol v3 servers
+     * (broadcast permission model). When connected to a protocol v2 server, the SDK
+     * will throw {@link IllegalStateException} because v2 expects exactly one
+     * response per permission request.
      */
     public static final PermissionRequestResultKind NO_RESULT = new PermissionRequestResultKind("no-result");
 

src/test/java/com/github/copilot/sdk/RpcHandlerDispatcherTest.java

@@ -25,6 +25,7 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.github.copilot.sdk.json.PermissionRequestResult;
+import com.github.copilot.sdk.json.PermissionRequestResultKind;
 import com.github.copilot.sdk.json.PreToolUseHookOutput;
 import com.github.copilot.sdk.json.SessionHooks;
 import com.github.copilot.sdk.json.SessionLifecycleEvent;
@@ -341,6 +342,25 @@ void permissionRequestHandlerFails() throws Exception {
         assertEquals("denied-no-approval-rule-and-could-not-request-from-user", result.get("kind").asText());
     }
 
+    @Test
+    void permissionRequestV2RejectsNoResult() throws Exception {
+        CopilotSession session = createSession("s1");
+        session.registerPermissionHandler((request, invocation) -> CompletableFuture
+                .completedFuture(new PermissionRequestResult().setKind(PermissionRequestResultKind.NO_RESULT)));
+
+        ObjectNode params = MAPPER.createObjectNode();
+        params.put("sessionId", "s1");
+        params.putObject("permissionRequest");
+
+        invokeHandler("permission.request", "13", params);
+
+        // V2 protocol does not support NO_RESULT — the handler should fall through
+        // to the exception path and respond with denied.
+        JsonNode response = readResponse();
+        JsonNode result = response.get("result").get("result");
+        assertEquals("denied-no-approval-rule-and-could-not-request-from-user", result.get("kind").asText());
+    }
+
     // ===== userInput.request tests =====
 
     @Test

src/test/java/com/github/copilot/sdk/SessionHandlerTest.java

@@ -17,6 +17,7 @@
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.github.copilot.sdk.json.PermissionRequestResult;
+import com.github.copilot.sdk.json.PermissionRequestResultKind;
 import com.github.copilot.sdk.json.SessionEndHookOutput;
 import com.github.copilot.sdk.json.SessionHooks;
 import com.github.copilot.sdk.json.SessionStartHookOutput;
@@ -115,6 +116,26 @@ void testHandlePermissionRequestHandlerSucceeds() throws Exception {
         assertEquals("allow", result.getKind());
     }
 
+    // ===== handlePermissionRequest: handler returns NO_RESULT (v3 path) =====
+
+    @Test
+    void testHandlePermissionRequestNoResultPassesThrough() throws Exception {
+        session.registerPermissionHandler((request, invocation) -> {
+            var res = new PermissionRequestResult();
+            res.setKind(PermissionRequestResultKind.NO_RESULT);
+            return CompletableFuture.completedFuture(res);
+        });
+
+        JsonNode data = MAPPER.valueToTree(Map.of("tool", "read_file"));
+
+        PermissionRequestResult result = session.handlePermissionRequest(data).get();
+
+        // In v3, NO_RESULT is a valid response — the session just returns it
+        // and the caller (CopilotSession.executePermissionAndRespondAsync) decides
+        // to skip sending the RPC response.
+        assertEquals("no-result", result.getKind());
+    }
+
     // ===== handleUserInputRequest: no handler registered =====
 
     @Test