[BUG] Chatwoot integration duplicates messages when a device re-delivers the same key.id — getExistingSourceIds exists but is never called on the live path

[CantinhodaPraia]

📋 Bug Description

When a sender's device re-delivers the same WhatsApp message (identical key.id, new timestamp — e.g. a buggy device or an unofficial client stuck in a loop resending an auto-reply), the Chatwoot integration creates a new Chatwoot message on every arrival. There is no idempotency check on the live path.

Real-world impact (production, v2.3.7): one guest's device looped an away-message roughly once a minute. In ~25h we accumulated 837 copies of a single message in one Chatwoot conversation (and a second looping key.id later reached 539 copies). The conversation became unusable for the support team. WhatsApp mobile shows the message once (native dedup by key.id); Chatwoot shows every copy.

The interesting part: the codebase already contains exactly the right check — ChatwootImport.getExistingSourceIds(sourceIds, conversationId) queries Chatwoot's messages.source_id for WAID:<key.id> — but it is only called from the history import path (importHistoryMessages). The live path (ChatwootService.createMessage) posts to Chatwoot with source_id: WAID:<key.id> without consulting anything.

🔄 Steps to Reproduce

1. Evolution API v2.3.7 (baileys channel) + Chatwoot integration enabled.
2. From a sender device, deliver the same message twice with the same key.id (a looping unofficial client does this naturally; the events arrive with status: DELIVERY_ACK, source: 'unknown' and a fresh messageTimestamp each time).
3. Watch the Chatwoot conversation.

✅ Expected Behavior

Second and subsequent arrivals of an already-imported key.id for the same conversation should be ignored (the same way importHistoryMessages already filters via getExistingSourceIds), or at least be configurable to be ignored.

❌ Actual Behavior

Every arrival creates a new Chatwoot message with the same source_id (WAID:<key.id>). messages.source_id in Chatwoot has a non-unique index, so nothing stops the duplicates downstream either.

💡 Suggested Fix

Call the existing check in the live path. We are running this in production (patched into createMessage) and it fully stopped the flood without affecting legitimate traffic:

// at the top of ChatwootService.createMessage(...), sourceId = "WAID:" + key.id
if (sourceId) {
  try {
    const existing = await chatwootImport.getExistingSourceIds([sourceId], conversationId);
    if (existing.has(sourceId)) {
      this.logger.warn(`[dedup] repeated message ignored source_id=${sourceId} conversation_id=${conversationId}`);
      return null; // callers already handle the null ("message not sent") path
    }
  } catch (e) {
    this.logger.warn(`[dedup] check unavailable: ${e}`); // fail open
  }
}

Notes:

• getExistingSourceIds already accepts the optional conversationId argument, so the lookup is cheap (indexed on source_id).
• Failing open on lookup errors keeps message delivery safe if the Chatwoot DB connection blips.
• Verified in production: 14 duplicate arrivals blocked in the first minutes across 2 looping key.ids, zero legitimate messages affected.

🌍 Environment

• Evolution API: v2.3.7 (image evoapicloud/evolution-api:v2.3.7)
• Connection type: baileys
• Chatwoot: v4.16.1, integration via CHATWOOT_ENABLED=true
• DB: PostgreSQL (shared instance for Evolution + Chatwoot import connection)
• OS: Linux (Docker)