v0.18.5 - Fix duplicate answer processing regression

The activeOffer.answered flag was being set AFTER the async
setRemoteDescription() call, creating a race condition window
where the same answer could be processed multiple times.

Root cause:
- Check `!activeOffer.answered` happens
- setRemoteDescription() starts (async operation)
- Before it completes, another check could happen
- Same answer gets processed twice → "stable" state error

Fix:
- Set activeOffer.answered = true BEFORE setRemoteDescription
- Add try/catch to reset flag if setRemoteDescription fails
- This prevents duplicate processing while allowing retries on error

This regression was introduced when the answered flag assignment
was not moved along with other polling logic changes.

Fixes: #6 regression

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package-lock.json

@@ -1,19 +1,19 @@
 {
   "name": "@xtr-dev/rondevu-client",
-  "version": "0.18.2",
+  "version": "0.18.5",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@xtr-dev/rondevu-client",
-      "version": "0.18.2",
+      "version": "0.18.5",
       "license": "MIT",
       "dependencies": {
-        "@noble/ed25519": "^3.0.0"
+        "@noble/ed25519": "^3.0.0",
+        "eventemitter3": "^5.0.1"
       },
       "devDependencies": {
         "@eslint/js": "^9.39.1",
-        "@types/node": "^25.0.2",
         "@typescript-eslint/eslint-plugin": "^8.48.1",
         "@typescript-eslint/parser": "^8.48.1",
         "eslint": "^9.39.1",
@@ -1082,6 +1082,8 @@
       "integrity": "sha512-gWEkeiyYE4vqjON/+Obqcoeffmk0NF15WSBwSs7zwVA2bAbTaE0SJ7P0WNGoJn8uE7fiaV5a7dKYIJriEqOrmA==",
       "dev": true,
       "license": "MIT",
+      "optional": true,
+      "peer": true,
       "dependencies": {
         "undici-types": "~7.16.0"
       }
@@ -2001,6 +2003,12 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/eventemitter3": {
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/eventemitter3/-/eventemitter3-5.0.1.tgz",
+      "integrity": "sha512-GWkBvjiSZK87ELrYOSESUYeVIc9mvLLf/nXalMOS5dYrgZq9o5OVkbZAVM06CVxYsCwH9BDZFPlQTlPA1j4ahA==",
+      "license": "MIT"
+    },
     "node_modules/fast-deep-equal": {
       "version": "3.1.3",
       "resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
@@ -2844,7 +2852,9 @@
       "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-7.16.0.tgz",
       "integrity": "sha512-Zz+aZWSj8LE6zoxD+xrjh4VfkIG8Ya6LvYkZqtUQGJPZjYl53ypCaUwWqo7eI0x66KBGeRo+mlBEkMSeSZ38Nw==",
       "dev": true,
-      "license": "MIT"
+      "license": "MIT",
+      "optional": true,
+      "peer": true
     },
     "node_modules/update-browserslist-db": {
       "version": "1.2.2",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@xtr-dev/rondevu-client",
-  "version": "0.18.2",
+  "version": "0.18.5",
   "description": "TypeScript client for Rondevu with durable WebRTC connections, automatic reconnection, and message queuing",
   "type": "module",
   "main": "dist/index.js",
@@ -25,7 +25,6 @@
   "license": "MIT",
   "devDependencies": {
     "@eslint/js": "^9.39.1",
-    "@types/node": "^25.0.2",
     "@typescript-eslint/eslint-plugin": "^8.48.1",
     "@typescript-eslint/parser": "^8.48.1",
     "eslint": "^9.39.1",
@@ -42,6 +41,7 @@
     "README.md"
   ],
   "dependencies": {
-    "@noble/ed25519": "^3.0.0"
+    "@noble/ed25519": "^3.0.0",
+    "eventemitter3": "^5.0.1"
   }
 }

src/rondevu.ts

@@ -1,6 +1,6 @@
 import { RondevuAPI, Keypair, IceCandidate, BatcherOptions } from './api.js'
 import { CryptoAdapter } from './crypto-adapter.js'
-import { EventEmitter } from 'events'
+import { EventEmitter } from 'eventemitter3'
 
 // ICE server preset names
 export type IceServerPreset = 'ipv4-turn' | 'hostname-turns' | 'google-stun' | 'relay-only'
@@ -259,6 +259,7 @@ export class Rondevu extends EventEmitter {
     private filling = false
     private pollingInterval: ReturnType<typeof setInterval> | null = null
     private lastPollTimestamp = 0
+    private isPolling = false  // Guard against concurrent poll execution
 
     private constructor(
         apiUrl: string,
@@ -634,6 +635,13 @@ export class Rondevu extends EventEmitter {
     private async pollInternal(): Promise<void> {
         if (!this.filling) return
 
+        // Prevent concurrent poll execution to avoid duplicate answer processing
+        if (this.isPolling) {
+            this.debug('Poll already in progress, skipping')
+            return
+        }
+
+        this.isPolling = true
         try {
             const result = await this.api.poll(this.lastPollTimestamp)
 
@@ -643,17 +651,25 @@ export class Rondevu extends EventEmitter {
                 if (activeOffer && !activeOffer.answered) {
                     this.debug(`Received answer for offer ${answer.offerId}`)
 
-                    await activeOffer.pc.setRemoteDescription({
+                    // Mark as answered BEFORE setRemoteDescription to prevent race condition
-                        type: 'answer',
-                        sdp: answer.sdp
-                    })
-
                     activeOffer.answered = true
-                    this.lastPollTimestamp = answer.answeredAt
-                    this.emit('offer:answered', answer.offerId, answer.answererId)
 
-                    // Create replacement offer
+                    try {
-                    this.fillOffers()
+                        await activeOffer.pc.setRemoteDescription({
+                            type: 'answer',
+                            sdp: answer.sdp
+                        })
+
+                        this.lastPollTimestamp = answer.answeredAt
+                        this.emit('offer:answered', answer.offerId, answer.answererId)
+
+                        // Create replacement offer
+                        this.fillOffers()
+                    } catch (err) {
+                        // If setRemoteDescription fails, reset the answered flag
+                        activeOffer.answered = false
+                        throw err
+                    }
                 }
             }
 
@@ -674,6 +690,8 @@ export class Rondevu extends EventEmitter {
             }
         } catch (err) {
             console.error('[Rondevu] Polling error:', err)
+        } finally {
+            this.isPolling = false
         }
     }
 
@@ -710,6 +728,7 @@ export class Rondevu extends EventEmitter {
     stopFilling(): void {
         this.debug('Stopping offer filling and polling')
         this.filling = false
+        this.isPolling = false  // Reset polling guard
 
         // Stop polling
         if (this.pollingInterval) {