Fixed improper shared pointer handling writing a .nfg file for an extensive game

Author: tturocy

ChangeLog

@@ -5,6 +5,8 @@
 ### Fixed
 - Fixed a regression in which null outcomes in strategic game tables were not handled correctly
   when changing the number of strategies in the game (#571)
+- Fixed improper shared pointer handling when writing a .nfg file based on a game in
+  extensive form.
 
 
 ## [16.3.2] - unreleased

src/games/behavmixed.h

@@ -226,7 +226,8 @@ template <class T> class MixedBehaviorProfile {
 template <class Generator>
 MixedBehaviorProfile<double> GameRep::NewRandomBehaviorProfile(Generator &generator) const
 {
-  auto profile = MixedBehaviorProfile<double>(Game(const_cast<GameRep *>(this)));
+  auto profile =
+      MixedBehaviorProfile<double>(std::const_pointer_cast<GameRep>(shared_from_this()));
   std::exponential_distribution<> dist(1); // NOLINT(misc-const-correctness)
   for (auto player : GetPlayers()) {
     for (auto infoset : player->GetInfosets()) {
@@ -242,7 +243,8 @@ template <class Generator>
 MixedBehaviorProfile<Rational> GameRep::NewRandomBehaviorProfile(int p_denom,
                                                                  Generator &generator) const
 {
-  auto profile = MixedBehaviorProfile<Rational>(Game(const_cast<GameRep *>(this)));
+  auto profile =
+      MixedBehaviorProfile<Rational>(std::const_pointer_cast<GameRep>(shared_from_this()));
   for (auto player : GetPlayers()) {
     for (auto infoset : player->GetInfosets()) {
       std::list<Rational> dist =

src/games/game.cc

@@ -213,8 +213,8 @@ void GameRep::WriteNfgFile(std::ostream &p_file) const
   p_file << "}" << std::endl;
   p_file << std::quoted(GetComment()) << std::endl << std::endl;
 
-  for (auto iter :
-       StrategyContingencies(StrategySupportProfile(Game(const_cast<GameRep *>(this))))) {
+  for (auto iter : StrategyContingencies(
+           StrategySupportProfile(std::const_pointer_cast<GameRep>(shared_from_this())))) {
     p_file << FormatList(
                   players,
                   [&iter](const GamePlayer &p) {

tests/test_io.py

@@ -63,6 +63,36 @@ def test_write_nfg():
     assert serialized_game[:3] == "NFG"
 
 
+def test_write_efg_as_nfg():
+    result = """
+NFG 1 R "Centipede game. Three inning with probability of altruism.  " { "Player 1" "Player 2" }
+
+{ { "1**111" "21*111" "221111" "222111" }
+{ "1**111" "21*111" "221111" "222111" }
+}
+""
+
+20027/25000 2689/12500
+541/1250 3983/2500
+3299/6250 5053/3125
+227/250 214/125
+5081/6250 3283/12500
+19931/6250 2677/3125
+5362/3125 19903/3125
+262/125 808/125
+2689/3125 5659/12500
+10114/3125 3271/3125
+39814/3125 10696/3125
+856/125 3184/125
+163/125 163/500
+92/25 23/25
+1648/125 412/125
+256/5 64/5
+"""
+    game = gbt.read_efg("tests/test_games/cent3.efg")
+    assert game.to_nfg().strip() == result.strip()
+
+
 def test_write_html():
     game = gbt.Game.new_table([2, 2])
     serialized_game = game.to_html()