From 38ae3047255d7050427e1d0e91f14cd338016490 Mon Sep 17 00:00:00 2001
From: Celtic Minstrel <celtic.minstrel.ca@some.place>
Date: Mon, 9 Oct 2023 14:24:30 -0400
Subject: [PATCH] Move Lua undo API into experimental

---
 data/lua/core/game_events.lua | 15 +++++++++++++++
 data/lua/diversion.lua        |  4 ++--
 data/lua/wml-tags.lua         |  8 ++++----
 3 files changed, 21 insertions(+), 6 deletions(-)
 create mode 100644 data/lua/core/game_events.lua

diff --git a/data/lua/core/game_events.lua b/data/lua/core/game_events.lua
new file mode 100644
index 00000000000..055000ead5e
--- /dev/null
+++ b/data/lua/core/game_events.lua
@@ -0,0 +1,15 @@
+--[========[Game Event Functions]========]
+
+if wesnoth.kernel_type() == "Game Lua Kernel" then
+    -- The undo API is still experimental, so move those functions
+
+    -- Make sure wesnoth.experimental.game_events actually exists
+    -- It's done this way so it doesn't break if we later need to add things here from C++
+    wesnoth.experimental = wesnoth.experimental or {}
+    wesnoth.experimental.game_events = wesnoth.experimental.game_events or {}
+
+    wesnoth.experimental.game_events.set_undoable = wesnoth.game_events.set_undoable
+    wesnoth.experimental.game_events.add_undo_actions = wesnoth.game_events.add_undo_actions
+    wesnoth.game_events.set_undoable = nil
+    wesnoth.game_events.add_undo_actions = nil
+end
diff --git a/data/lua/diversion.lua b/data/lua/diversion.lua
index f6bb465f9cc..c7ab6ced504 100644
--- a/data/lua/diversion.lua
+++ b/data/lua/diversion.lua
@@ -87,9 +87,9 @@ local function status_anim_update(is_undo)
                 end
         end
         if not is_undo then
-                wesnoth.game_events.set_undoable(true)
+                wesnoth.experimental.game_events.set_undoable(true)
                 if changed_something then
-                        wesnoth.game_events.add_undo_actions(function(_)
+                        wesnoth.experimental.game_events.add_undo_actions(function(_)
                                 status_anim_update(true)
                         end)
                 end
diff --git a/data/lua/wml-tags.lua b/data/lua/wml-tags.lua
index 29b089f27d5..9be94779941 100644
--- a/data/lua/wml-tags.lua
+++ b/data/lua/wml-tags.lua
@@ -645,11 +645,11 @@ function wml_actions.put_to_recall_list(cfg)
 end
 
 function wml_actions.allow_undo(cfg)
-	wesnoth.game_events.set_undoable(true)
+	wesnoth.experimental.game_events.set_undoable(true)
 end
 
 function wml_actions.disallow_undo(cfg)
-	wesnoth.game_events.set_undoable(false)
+	wesnoth.experimental.game_events.set_undoable(false)
 end
 
 function wml_actions.allow_end_turn(cfg)
@@ -1032,8 +1032,8 @@ end
 
 function wml_actions.on_undo(cfg)
 	if cfg.delayed_variable_substitution then
-		wesnoth.game_events.add_undo_actions(wml.literal(cfg));
+		wesnoth.experimental.game_events.add_undo_actions(wml.literal(cfg));
 	else
-		wesnoth.game_events.add_undo_actions(wml.parsed(cfg));
+		wesnoth.experimental.game_events.add_undo_actions(wml.parsed(cfg));
 	end
 end