## Release v0.51.235 — Release HC (stage-q5)
Single fix in the data-sensitive transcript-merge path, with a Codex-found MUST-FIX applied.
### Fix
| PR | Author | Fix |
|----|--------|-----|
| #3468 | @jasonjcwu | `_find_current_user_turn` returns the **last** matching user turn instead of the first, so post-compression `result_messages` (which carries the full history) no longer replays the entire conversation when the user repeats a similar question (137-msg session → 89 duplicate replays). |
### Pre-release review caught a CORE issue (fixed before ship)
Codex's regression gate found that a naive last-match could be overridden by a **synthetic `role:"user"` continuation prompt** (the agent loop injects "Continue"/empty-recovery nudges — verified at `conversation_loop.py:1763/4183/4356`) that only *substring*-matches the user text — anchoring the merge **past** the real turn and dropping the assistant/tool output in between. Applied the fix: track **strong** (exact `_looks_like_current_user_turn`) and **weak** (substring) matches separately and return `last_strong → last_weak → fallback`. The real turn (strong) always wins over a later synthetic continuation (weak).
Opus reviewed the original and said ship; the applied fix is strictly safer than what it reviewed.
### Gate results
- **Full pytest suite**: 7465 passed, 8 skipped, 3 xpassed, **0 failed**
- **ruff forward gate**: CLEAN
- **browser-smoke gate**: CLEAN
- **Codex (regression)**: SHIP ONLY WITH FIXES → fix applied → re-reviewed **SAFE TO SHIP**
- **Opus (correctness)**: SHIP IT (on the pre-fix code; applied fix is strictly safer)
- **Regression test** (`tests/test_issue3468_duplicate_after_compression.py`, 7 cases): pins the last-match behavior, the strong-beats-later-weak invariant, and the end-to-end no-duplicate-replay invariant — each **verified to fail against the pre-fix logic**.
Co-authored-by: jasonjcwu <jasonjcwu@users.noreply.github.com>
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