[eli-r-ph]

💡 Motivation and Context

The 8.0 migration guide says an event that can't be serialized to JSON, such as one with a circular reference, is dropped and logged. Since #1120 removed the non-finite case, no test checks that such an event costs only itself and not its batch.

• Add a circular-reference case to test_malformed_before_send_event_does_not_stop_consumer_or_shutdown: the bad event is dropped, the valid event in the same batch is sent, and the consumer and shutdown still finish.

💚 How did you test it?

pytest posthog/test/test_before_send.py -k malformed: 2 passed. Without the per-event serialization guard, the whole batch fails to serialize and the valid event is never sent, so the case fails.

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Claude Code (Claude Opus 5.5) added this test in response to a review comment on #1120.

🤖 Generated with Claude Code