fix(coding-runtime): close Pi extension lifecycle races

electron/coding-runtime/pi/interaction.ts

@@ -13,6 +13,7 @@ interface StoredInteraction {
   interaction: ConversationInteraction;
   generation: number;
   labels: Map<string, string>;
+  phase: 'pending' | 'responding';
   untrack(): void;
 }
 
@@ -85,6 +86,7 @@ export class PiInteractionStore {
       interaction,
       generation,
       labels,
+      phase: 'pending',
       untrack: () => undefined,
     };
     stored.untrack = this.transport.trackGenerationResource({
@@ -102,6 +104,7 @@ export class PiInteractionStore {
   async respond(conversationId: string, response: PiInteractionResponse): Promise<ConversationInteraction> {
     const stored = this.pending.get(this.key(conversationId, response.interactionId));
     if (!stored) throw new Error('Pi interaction is not pending');
+    if (stored.phase === 'responding') throw new Error('Pi interaction response is already in progress');
     const state = this.transport.getState(conversationId);
     const active = this.transport.getActiveRun(conversationId);
     if (state?.generation !== stored.generation
@@ -126,7 +129,18 @@ export class PiInteractionStore {
     } else {
       throw new Error('Pi interaction response does not match its kind');
     }
-    await this.transport.send(conversationId, command);
+    stored.phase = 'responding';
+    try {
+      await this.transport.send(conversationId, command);
+    } catch (error) {
+      if (this.pending.get(this.key(conversationId, stored.interaction.id)) === stored) {
+        stored.phase = 'pending';
+      }
+      throw error;
+    }
+    if (this.pending.get(this.key(conversationId, stored.interaction.id)) !== stored) {
+      throw new Error('Pi interaction belongs to a stale worker run');
+    }
     return this.finish(stored, 'cancelled' in response
       ? 'cancelled'
       : stored.interaction.kind === 'confirm' && 'confirmed' in response && !response.confirmed