Python: ag-ui _deduplicate_messages catch-all branch can drop valid repeated messages

[moonbox3]

The catch-all branch in _deduplicate_messages (lines 244-253 of _message_adapters.py) deduplicates by (role, hash(content_str)), which means any two messages with the same role and identical content are treated as duplicates. This can incorrectly drop valid repeated messages — e.g., a user saying "yes" to confirm two separate things.

The tool-specific dedup branches (tool results by call_id, assistant tool calls by call_id tuple) are correct and should remain. The fix should either remove the catch-all branch or scope it more tightly (e.g., only dedup adjacent identical messages, or use message IDs from the AG-UI protocol).

Ref: #4640

[SogoKato]

Hi, thanks for looking into this and creating the PR!

I’ve also been working on a local fix for this issue. I noticed your PR focuses on deduplicating consecutive messages, but my approach uses message_id to ensure unique identification.

Since these are slightly different strategies, I was wondering if you’d be interested in seeing my version as well, or if we should discuss the pros and cons of using message_id here before I open a Pull Request?

[moonbox3]

Hi, thanks for looking into this and creating the PR!

I’ve also been working on a local fix for this issue. I noticed your PR focuses on deduplicating consecutive messages, but my approach uses message_id to ensure unique identification.

Since these are slightly different strategies, I was wondering if you’d be interested in seeing my version as well, or if we should discuss the pros and cons of using message_id here before I open a Pull Request?

Thanks for the message, @SogoKato. It's funny you say this because I was actually in the middle of moving towards this strategy, as well. Currently testing things, and then I will push.