From 72eb60f3229482b6e11389e3f3146a6781b84a9c Mon Sep 17 00:00:00 2001
From: Henri Bourcereau <henri.bourcereau@gmail.com>
Date: Fri, 27 Feb 2026 18:08:21 +0100
Subject: [PATCH] fix(bot): raise error on empty get_legal_actions

---
 store/src/cxxengine.rs       | 33 +++++++++++++++++----------------
 store/src/pyengine.rs        |  4 ++--
 store/src/training_common.rs | 15 ++++++++-------
 3 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/store/src/cxxengine.rs b/store/src/cxxengine.rs
index 86aa382..e6027f6 100644
--- a/store/src/cxxengine.rs
+++ b/store/src/cxxengine.rs
@@ -57,7 +57,7 @@ pub mod ffi {
 
         /// Legal action indices for `player_idx` in [0, 513].
         /// Returns an empty vector when it is not that player's turn.
-        fn get_legal_actions(self: &TricTracEngine, player_idx: u64) -> Vec<u64>;
+        fn get_legal_actions(self: &TricTracEngine, player_idx: u64) -> Result<Vec<u64>>;
 
         /// Human-readable description of an action index.
         fn action_to_string(self: &TricTracEngine, player_idx: u64, action_idx: u64) -> String;
@@ -123,21 +123,16 @@ impl TricTracEngine {
         self.game_state.active_player_id - 1
     }
 
-    fn get_legal_actions(&self, player_idx: u64) -> Vec<u64> {
+    fn get_legal_actions(&self, player_idx: u64) -> anyhow::Result<Vec<u64>> {
         if player_idx != self.current_player_idx() {
-            return vec![];
+            return Ok(vec![]);
         }
         if player_idx == 0 {
             get_valid_action_indices(&self.game_state)
-                .into_iter()
-                .map(|i| i as u64)
-                .collect()
+                .map(|v| v.into_iter().map(|i| i as u64).collect())
         } else {
             let mirror = self.game_state.mirror();
-            get_valid_action_indices(&mirror)
-                .into_iter()
-                .map(|i| i as u64)
-                .collect()
+            get_valid_action_indices(&mirror).map(|v| v.into_iter().map(|i| i as u64).collect())
         }
     }
 
@@ -184,8 +179,10 @@ impl TricTracEngine {
 
     fn apply_dice_roll(&mut self, dice: ffi::DicePair) -> anyhow::Result<()> {
         if self.game_state.turn_stage != TurnStage::RollWaiting {
-            anyhow::bail!("apply_dice_roll: not in RollWaiting stage (currently {:?})",
-                self.game_state.turn_stage);
+            anyhow::bail!(
+                "apply_dice_roll: not in RollWaiting stage (currently {:?})",
+                self.game_state.turn_stage
+            );
         }
         let player_id = self.game_state.active_player_id;
         let dice = Dice {
@@ -214,10 +211,14 @@ impl TricTracEngine {
                 self.game_state.consume(&evt);
                 Ok(())
             }
-            Some(_) => anyhow::bail!("apply_action: action {} is not valid in current state",
-                action_idx),
-            None => anyhow::bail!("apply_action: could not build event from action index {}",
-                action_idx),
+            Some(_) => anyhow::bail!(
+                "apply_action: action {} is not valid in current state",
+                action_idx
+            ),
+            None => anyhow::bail!(
+                "apply_action: could not build event from action index {}",
+                action_idx
+            ),
         }
     }
 }
diff --git a/store/src/pyengine.rs b/store/src/pyengine.rs
index 7577954..593fa00 100644
--- a/store/src/pyengine.rs
+++ b/store/src/pyengine.rs
@@ -43,10 +43,10 @@ impl TricTrac {
     fn get_legal_actions(&self, player_idx: u64) -> Vec<usize> {
         if player_idx == self.current_player_idx() {
             if player_idx == 0 {
-                get_valid_action_indices(&self.game_state)
+                get_valid_action_indices(&self.game_state).unwrap()
             } else {
                 let mirror = self.game_state.mirror();
-                get_valid_action_indices(&mirror)
+                get_valid_action_indices(&mirror).unwrap()
             }
         } else {
             vec![]
diff --git a/store/src/training_common.rs b/store/src/training_common.rs
index 6427ea4..0cc635c 100644
--- a/store/src/training_common.rs
+++ b/store/src/training_common.rs
@@ -195,7 +195,7 @@ impl TrictracAction {
 }
 
 /// Obtient les actions valides pour l'état de jeu actuel
-pub fn get_valid_actions(game_state: &GameState) -> Vec<TrictracAction> {
+pub fn get_valid_actions(game_state: &GameState) -> anyhow::Result<Vec<TrictracAction>> {
     use crate::TurnStage;
 
     let mut valid_actions = Vec::new();
@@ -246,9 +246,9 @@ pub fn get_valid_actions(game_state: &GameState) -> Vec<TrictracAction> {
     }
 
     if valid_actions.is_empty() {
-        panic!("empty valid_actions for state {game_state}");
+        anyhow::bail!("empty valid_actions for state {game_state}");
     }
-    valid_actions
+    Ok(valid_actions)
 }
 
 fn checker_moves_to_trictrac_action(
@@ -336,11 +336,12 @@ fn white_checker_moves_to_trictrac_action(
 }
 
 /// Retourne les indices des actions valides
-pub fn get_valid_action_indices(game_state: &GameState) -> Vec<usize> {
-    get_valid_actions(game_state)
+pub fn get_valid_action_indices(game_state: &GameState) -> anyhow::Result<Vec<usize>> {
+    let actions = get_valid_actions(game_state)?;
+    Ok(actions
         .into_iter()
         .map(|action| action.to_action_index())
-        .collect()
+        .collect())
 }
 
 /// Sélectionne une action valide aléatoire
@@ -349,7 +350,7 @@ pub fn sample_valid_action(game_state: &GameState) -> Option<TrictracAction> {
 
     let valid_actions = get_valid_actions(game_state);
     let mut rng = rng();
-    valid_actions.choose(&mut rng).cloned()
+    valid_actions.unwrap().choose(&mut rng).cloned()
 }
 
 #[cfg(test)]