Cache Canonical Messages in Cleanup Loop

Cache Canonical Messages in Cleanup Loop

Summary

The sanitize cleanup loop re-canonicalized messages multiple times per iteration. We now cache canonical messages per iteration, recomputing only after mutations, and remove the double conversion inside find_dangling_tool_calls().

Context

• Files: src/tunacode/core/agents/resume/sanitize.py, src/tunacode/utils/messaging/adapter.py
• Symptom: redundant to_canonical() calls during cleanup iterations.

Root Cause

Canonicalization was happening in each cleanup helper (and twice per message in find_dangling_tool_calls()), so a single iteration performed multiple full conversions of the same message list.

Changes

• Converted each message once inside find_dangling_tool_calls() by reusing a single canonical instance.
• Cached canonical messages at the start of each cleanup iteration and recomputed only after mutations.
• Added canonical cache passthroughs to remove_empty_responses() and remove_consecutive_requests().
• Added a unit test to verify 1N conversions in a no-mutation iteration.

Behavioral Impact

• Cleanup iterations now run with fewer canonicalization passes (1N without mutations, 2N when deletions occur).
• Cleanup behavior and tool-call pruning logic remain unchanged.

Related Cards

• [[message-history]]
• [[sanitize-loop]]