From 6e0e0324a48130376ab3c9fef03b84ee25608242 Mon Sep 17 00:00:00 2001
From: rubenwardy <rw@rubenwardy.com>
Date: Sun, 31 Jan 2021 18:49:51 +0000
Subject: [PATCH] Fix minetest.dig_node returning true when node isn't diggable
 (#10890)

---
 builtin/game/item.lua         |  6 ++++--
 doc/lua_api.txt               |  2 ++
 src/script/cpp_api/s_node.cpp | 11 ++++++++---
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/builtin/game/item.lua b/builtin/game/item.lua
index 63f8d50e5..881aff52e 100644
--- a/builtin/game/item.lua
+++ b/builtin/game/item.lua
@@ -557,7 +557,7 @@ function core.node_dig(pos, node, digger)
 		log("info", diggername .. " tried to dig "
 			.. node.name .. " which is not diggable "
 			.. core.pos_to_string(pos))
-		return
+		return false
 	end
 
 	if core.is_protected(pos, diggername) then
@@ -566,7 +566,7 @@ function core.node_dig(pos, node, digger)
 				.. " at protected position "
 				.. core.pos_to_string(pos))
 		core.record_protection_violation(pos, diggername)
-		return
+		return false
 	end
 
 	log('action', diggername .. " digs "
@@ -649,6 +649,8 @@ function core.node_dig(pos, node, digger)
 		local node_copy = {name=node.name, param1=node.param1, param2=node.param2}
 		callback(pos_copy, node_copy, digger)
 	end
+
+	return true
 end
 
 function core.itemstring_with_palette(item, palette_index)
diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 8156f785a..df9e3f8b0 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -7628,6 +7628,8 @@ Used by `minetest.register_node`.
         on_dig = function(pos, node, digger),
         -- default: minetest.node_dig
         -- By default checks privileges, wears out tool and removes node.
+        -- return true if the node was dug successfully, false otherwise.
+        -- Deprecated: returning nil is the same as returning true.
 
         on_timer = function(pos, elapsed),
         -- default: nil
diff --git a/src/script/cpp_api/s_node.cpp b/src/script/cpp_api/s_node.cpp
index 269ebacb2..f23fbfbde 100644
--- a/src/script/cpp_api/s_node.cpp
+++ b/src/script/cpp_api/s_node.cpp
@@ -141,9 +141,14 @@ bool ScriptApiNode::node_on_dig(v3s16 p, MapNode node,
 	push_v3s16(L, p);
 	pushnode(L, node, ndef);
 	objectrefGetOrCreate(L, digger);
-	PCALL_RES(lua_pcall(L, 3, 0, error_handler));
-	lua_pop(L, 1);  // Pop error handler
-	return true;
+	PCALL_RES(lua_pcall(L, 3, 1, error_handler));
+
+	// nil is treated as true for backwards compat
+	bool result = lua_isnil(L, -1) || lua_toboolean(L, -1);
+
+	lua_pop(L, 2);  // Pop error handler and result
+
+	return result;
 }
 
 void ScriptApiNode::node_on_construct(v3s16 p, MapNode node)