fix(coding-agent): stop RpcClient skipping listeners on unsubscribe

closes #9990

packages/coding-agent/CHANGELOG.md

@@ -15,6 +15,7 @@
 - Fixed X11 clipboard text being misidentified as an image when the clipboard owner accepts unadvertised image targets ([#9786](https://github.com/earendil-works/pi/issues/9786)).
 - Prevented managed git packages from automatically installing Pi peer dependencies and added warnings for extension packages that list host-provided modules in `dependencies` ([#9863](https://github.com/earendil-works/pi/issues/9863)).
 - Fixed pinned git extensions loaded with `-e` continuing to use the first downloaded commit after the ref changes ([#9982](https://github.com/earendil-works/pi/issues/9982)).
+- Fixed `RpcClient` skipping the next event listener when a listener unsubscribes while handling an event, which could make `waitForIdle()` time out after `collectEvents()` ([#9990](https://github.com/earendil-works/pi/issues/9990)).
 
 ## [0.87.1] - 2026-09-22
 

packages/coding-agent/src/modes/rpc/rpc-client.ts

@@ -525,8 +525,9 @@ export class RpcClient {
 				return;
 			}
 
-			// Otherwise it's an event
-			for (const listener of this.eventListeners) {
+			// Otherwise it's an event. Iterate a snapshot so listeners that unsubscribe during dispatch
+			// do not cause later listeners to miss this event.
+			for (const listener of [...this.eventListeners]) {
 				listener(data as JsonAgentSessionEvent);
 			}
 		} catch {