From 24263ccbb05971e57adaf6f88338b9579da0ef95 Mon Sep 17 00:00:00 2001
From: ashtrayoz <33517241+ashtrayoz@users.noreply.github.com>
Date: Thu, 9 Nov 2017 23:29:04 +1100
Subject: [PATCH] Add callback to preserve node metadata as item metadata

---
 builtin/game/falling.lua | 16 +++++++++++++++-
 builtin/game/item.lua    | 14 ++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/builtin/game/falling.lua b/builtin/game/falling.lua
index 1876cf2..436350f 100644
--- a/builtin/game/falling.lua
+++ b/builtin/game/falling.lua
@@ -150,8 +150,22 @@ end
 
 local function drop_attached_node(p)
 	local n = core.get_node(p)
+	local drops = core.get_node_drops(n, "")
+	local def = core.registered_items[n.name]
+	if def and def.preserve_metadata then
+		local oldmeta = core.get_meta(p):to_table().fields
+		-- Copy pos and node because the callback can modify them.
+		local pos_copy = {x=p.x, y=p.y, z=p.z}
+		local node_copy = {name=n.name, param1=n.param1, param2=n.param2}
+		local drop_stacks = {}
+		for k, v in pairs(drops) do
+			drop_stacks[k] = ItemStack(v)
+		end
+		drops = drop_stacks
+		def.preserve_metadata(pos_copy, node_copy, oldmeta, drops)
+	end
 	core.remove_node(p)
-	for _, item in pairs(core.get_node_drops(n, "")) do
+	for _, item in pairs(drops) do
 		local pos = {
 			x = p.x + math.random()/2 - 0.25,
 			y = p.y + math.random()/2 - 0.25,
diff --git a/builtin/game/item.lua b/builtin/game/item.lua
index 5e5696f..a717671 100644
--- a/builtin/game/item.lua
+++ b/builtin/game/item.lua
@@ -579,6 +579,20 @@ function core.node_dig(pos, node, digger)
 		digger:set_wielded_item(wielded)
 	end
 
+	-- Check to see if metadata should be preserved.
+	if def and def.preserve_metadata then
+		local oldmeta = core.get_meta(pos):to_table().fields
+		-- Copy pos and node because the callback can modify them.
+		local pos_copy = {x=pos.x, y=pos.y, z=pos.z}
+		local node_copy = {name=node.name, param1=node.param1, param2=node.param2}
+		local drop_stacks = {}
+		for k, v in pairs(drops) do
+			drop_stacks[k] = ItemStack(v)
+		end
+		drops = drop_stacks
+		def.preserve_metadata(pos_copy, node_copy, oldmeta, drops)
+	end
+
 	-- Handle drops
 	core.handle_node_drops(pos, drops, digger)