Phase 3 of the in-place card_game rewrite.
Two bugs on undo:
1. recycle_count was incremented when recycling but never decremented on
undo, causing the free-recycle allowance to be exhausted faster than
it should be after undo+redo cycles.
2. undoing a penalised recycle applied the −15 undo penalty on top of
the post-penalty (post-recycle) score rather than on the pre-recycle
score, compounding the −100 / −20 penalty rather than reversing it.
Fix:
- Add score_history: Vec<i32> and is_recycle_history: Vec<bool> to
GameState, both parallel to session.history() at all times.
- Extract pre_instruction_score_delta() helper — single source of truth
for all scoring logic, called from draw(), move_cards(), and the
Deserialize replay.
- draw() and move_cards() push to both stacks before processing.
- undo() pops from both stacks: uses the popped pre-move score as the
base for apply_undo_score() and decrements recycle_count if the
undone instruction was a recycle.
- Deserialize rebuilds is_recycle_history and recycle_count from the
instruction replay (recycle detection needs only pre-instruction
session state, so it is always correct across save/load cycles).
score_history is not rebuilt on load (undo-penalty history is absent
from saved_moves); undo falls back to old behaviour for pre-load
moves, but is fully correct for moves made in the current session.
- Remove recycle_count from PersistedGameStateIn (now rebuilt; serde
silently ignores the field in existing JSON saves).
Tests added:
- recycle_count_decrements_when_recycle_is_undone
- score_recycle_penalty_is_reversed_on_undo
All 71 solitaire_core tests and full-workspace suite pass; clippy clean.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
funman300
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