When a broadcast is paused or stopped while live streaming is active, the application throws a Convex validation error:

ArgumentValidationError: Value does not match validator.
Path: .session_id
Value: null
Validator: v.string()

This error occurs due to a race condition in the HostAgentService. When the stop() method is called, it asynchronously ends the session and sets this.currentSessionId = null. However, ongoing async operations like saveNarrationToDatabase() may still be running and attempt to call incrementHostSessionStats with the now-null session ID.

Root Cause

The issue happens in this sequence:

1. Live streaming is active with narrations being processed
2. User pauses/stops the broadcast
3. stop() method calls endSession() which sets this.currentSessionId = null
4. Meanwhile, saveNarrationToDatabase() is still executing async operations
5. When it reaches the incrementHostSessionStats call, it passes null instead of a valid session ID

Solution

Store the session ID in a local variable at the beginning of the saveNarrationToDatabase method to prevent race conditions. This ensures all database operations within the method use the same valid session ID that was active when the method started.

Changes made:

• Added const sessionId = this.currentSessionId after the initial null check
• Updated all database mutation calls to use the local sessionId instead of this.currentSessionId
• This prevents the validation error while maintaining all existing functionality

The fix is minimal and surgical, addressing only the specific race condition without affecting any other parts of the system.

Fixes #19.

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