Fix meta tool capabilities regression (#16563)

This also adds a unittest to avoid issues in the future.

games/devtest/mods/unittests/metadata.lua

@@ -128,3 +128,42 @@ local function test_node_metadata(player, pos)
 	test_metadata(core.get_meta(pos))
 end
 unittests.register("test_node_metadata", test_node_metadata, {map=true})
+
+local function get_cracky_cap(item)
+	local value = item:get_tool_capabilities()
+	assert(type(value) == "table")
+	value = value.groupcaps
+	assert(type(value) == "table")
+	value = value.cracky
+	assert(type(value) == "table")
+	value = value.times
+	assert(type(value) == "table")
+	value = value[1]
+	assert(type(value) == "number")
+	return value
+end
+
+local function test_item_metadata_tool_capabilities()
+	local test_caps = {
+		groupcaps={
+			cracky={times={123}},
+		},
+	}
+
+	-- has no tool capabilities
+	local item = ItemStack("unittests:stick")
+	local item_meta = item:get_meta()
+	assert(dump(item:get_tool_capabilities()) == dump(ItemStack(""):get_tool_capabilities()))
+	item_meta:set_tool_capabilities(test_caps)
+	-- Can't directly compare the tables, because the pushback to Lua from get_tool_capabilities()
+	-- adds values to left out fields of the tool capabilities table.
+	assert(get_cracky_cap(item) == 123)
+
+	-- has preexisting tool capabilities in its definition table
+	item = ItemStack("unittests:unrepairable_tool")
+	item_meta = item:get_meta()
+	assert(get_cracky_cap(item) == 3)
+	item_meta:set_tool_capabilities(test_caps)
+	assert(get_cracky_cap(item) == 123)
+end
+unittests.register("test_item_metadata_tool_capabilities", test_item_metadata_tool_capabilities)

src/inventory.h

@@ -106,18 +106,24 @@ struct ItemStack
 	const ToolCapabilities& getToolCapabilities(
 			const IItemDefManager *itemdef, const ItemStack *hand = nullptr) const
 	{
-		const ToolCapabilities *item_cap = itemdef->get(name).tool_capabilities;
+		// Check for override
+		auto &meta_item_cap = metadata.getToolCapabilitiesOverride();
+		if (meta_item_cap.has_value())
+			return meta_item_cap.value();
 
-		if (item_cap) {
-			return metadata.getToolCapabilities(*item_cap); // Check for override
-		}
+		const ToolCapabilities *item_cap = itemdef->get(name).tool_capabilities;
+		if (item_cap)
+			return *item_cap;
 
 		// Fall back to the hand's tool capabilities
 		if (hand) {
+			auto &hand_meta_item_cap = hand->metadata.getToolCapabilitiesOverride();
+			if (hand_meta_item_cap.has_value())
+				return hand_meta_item_cap.value();
+
 			item_cap = itemdef->get(hand->name).tool_capabilities;
-			if (item_cap) {
-				return hand->metadata.getToolCapabilities(*item_cap);
-			}
+			if (item_cap)
+				return *item_cap;
 		}
 
 		item_cap = itemdef->get("").tool_capabilities;

src/itemstackmetadata.h

@@ -23,10 +23,9 @@ public:
 	void serialize(std::ostream &os) const;
 	void deSerialize(std::istream &is);
 
-	const ToolCapabilities &getToolCapabilities(
-			const ToolCapabilities &default_caps) const
+	const std::optional<ToolCapabilities> &getToolCapabilitiesOverride() const
 	{
-		return toolcaps_override.has_value() ? *toolcaps_override : default_caps;
+		return toolcaps_override;
 	}
 
 	void setToolCapabilities(const ToolCapabilities &caps);