Allow game to specify first and last mod in mod loading order (#14177)

Co-authored-by: Lars Mueller <appgurulars@gmx.de>
Co-authored-by: sfan5 <sfan5@live.de>

doc/lua_api.md

@@ -63,6 +63,8 @@ The game directory can contain the following files:
     * `name`: (Deprecated) same as title.
     * `description`: Short description to be shown in the content tab.
       See [Translating content meta](#translating-content-meta).
+    * `first_mod`: Use this to specify the mod that must be loaded before any other mod.
+    * `last_mod`: Use this to specify the mod that must be loaded after all other mods
     * `allowed_mapgens = <comma-separated mapgens>`
       e.g. `allowed_mapgens = v5,v6,flat`
       Mapgens not in this list are removed from the list of mapgens for the

games/devtest/game.conf

@@ -1,2 +1,4 @@
 title = Development Test
 description = Testing environment to help with testing the engine features of Minetest. It can also be helpful in mod development.
+first_mod = first_mod
+last_mod = last_mod

games/devtest/mods/first_mod/init.lua

@@ -0,0 +1 @@
+-- Nothing to do here, loading order is tested in C++ unittests.

games/devtest/mods/first_mod/mod.conf

@@ -0,0 +1,2 @@
+name = first_mod
+description = Mod which should be loaded before every other mod.

games/devtest/mods/last_mod/init.lua

@@ -0,0 +1 @@
+-- Nothing to do here, loading order is tested in C++ unittests.

games/devtest/mods/last_mod/mod.conf

@@ -0,0 +1,5 @@
+name = last_mod
+description = Mod which should be loaded as last mod.
+# Test dependencies
+optional_depends = unittests
+depends = first_mod

games/devtest/mods/unittests/mod.conf

@@ -1,3 +1,4 @@
 name = unittests
 description = Adds automated unit tests for the engine
-depends = basenodes
+# Also test that it is possible to depend on first_mod
+depends = first_mod, basenodes

src/content/mod_configuration.cpp

@@ -24,7 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "gettext.h"
 #include "exceptions.h"
 #include "util/numeric.h"
-
+#include <optional>
 
 std::string ModConfiguration::getUnsatisfiedModsError() const
 {
@@ -116,6 +116,9 @@ void ModConfiguration::addGameMods(const SubgameSpec &gamespec)
 	std::string game_virtual_path;
 	game_virtual_path.append("games/").append(gamespec.id).append("/mods");
 	addModsInPath(gamespec.gamemods_path, game_virtual_path);
+
+	m_first_mod = gamespec.first_mod;
+	m_last_mod = gamespec.last_mod;
 }
 
 void ModConfiguration::addModsFromConfig(
@@ -221,13 +224,20 @@ void ModConfiguration::checkConflictsAndDeps()
 
 void ModConfiguration::resolveDependencies()
 {
-	// Step 1: Compile a list of the mod names we're working with
+	// Compile a list of the mod names we're working with
 	std::set<std::string> modnames;
-	for (const ModSpec &mod : m_unsatisfied_mods) {
+	std::optional<ModSpec> first_mod_spec, last_mod_spec;
+	for (ModSpec &mod : m_unsatisfied_mods) {
+		if (mod.name == m_first_mod) {
+			first_mod_spec = mod;
+		} else if (mod.name == m_last_mod) {
+			last_mod_spec = mod;
+		} else {
 			modnames.insert(mod.name);
 		}
+	}
 
-	// Step 1.5 (optional): shuffle unsatisfied mods so non declared depends get found by their devs
+	// Optionally shuffle unsatisfied mods so non declared depends get found by their devs
 	if (g_settings->getBool("random_mod_load_order")) {
 		MyRandGenerator rg;
 		std::shuffle(m_unsatisfied_mods.begin(),
@@ -236,25 +246,55 @@ void ModConfiguration::resolveDependencies()
 		);
 	}
 
-	// Step 2: get dependencies (including optional dependencies)
+	// Check for presence of first and last mod
+	if (!m_first_mod.empty() && !first_mod_spec.has_value())
+		throw ModError("The mod specified as first by the game was not found.");
+	if (!m_last_mod.empty() && !last_mod_spec.has_value())
+		throw ModError("The mod specified as last by the game was not found.");
+
+	// Check and add first mod
+	if (first_mod_spec.has_value()) {
+		// Dependencies are not allowed for first mod
+		if (!first_mod_spec->depends.empty() || !first_mod_spec->optdepends.empty())
+			throw ModError("Mod specified by first_mod cannot have dependencies");
+
+		m_sorted_mods.push_back(*first_mod_spec);
+	}
+
+	// Get dependencies (including optional dependencies)
 	// of each mod, split mods into satisfied and unsatisfied
 	std::vector<ModSpec> satisfied;
 	std::list<ModSpec> unsatisfied;
 	for (ModSpec mod : m_unsatisfied_mods) {
+		if (mod.name == m_first_mod || mod.name == m_last_mod)
+			continue; // skip, handled separately
+
 		mod.unsatisfied_depends = mod.depends;
 		// check which optional dependencies actually exist
 		for (const std::string &optdep : mod.optdepends) {
 			if (modnames.count(optdep) != 0)
 				mod.unsatisfied_depends.insert(optdep);
 		}
+		mod.unsatisfied_depends.erase(m_first_mod); // first is already satisfied
+
+		if (last_mod_spec.has_value() && mod.unsatisfied_depends.count(last_mod_spec->name) != 0) {
+			throw ModError("Impossible to depend on the mod specified by last_mod");
+		}
 		// if a mod has no depends it is initially satisfied
-		if (mod.unsatisfied_depends.empty())
+		if (mod.unsatisfied_depends.empty()) {
 			satisfied.push_back(mod);
-		else
+		} else {
 			unsatisfied.push_back(mod);
 		}
+	}
 
-	// Step 3: mods without unmet dependencies can be appended to
+	// All dependencies of the last mod are initially unsatisfied
+	if (last_mod_spec.has_value()) {
+		last_mod_spec->unsatisfied_depends = last_mod_spec->depends;
+		last_mod_spec->unsatisfied_depends.erase(m_first_mod);
+	}
+
+	// Mods without unmet dependencies can be appended to
 	// the sorted list.
 	while (!satisfied.empty()) {
 		ModSpec mod = satisfied.back();
@@ -270,8 +310,18 @@ void ModConfiguration::resolveDependencies()
 				++it;
 			}
 		}
+		if (last_mod_spec.has_value())
+			last_mod_spec->unsatisfied_depends.erase(mod.name);
 	}
 
-	// Step 4: write back list of unsatisfied mods
+	// Write back list of unsatisfied mods
 	m_unsatisfied_mods.assign(unsatisfied.begin(), unsatisfied.end());
+
+	// Check and add last mod
+	if (last_mod_spec.has_value()) {
+		if (last_mod_spec->unsatisfied_depends.empty())
+			m_sorted_mods.push_back(*last_mod_spec);
+		else
+			m_unsatisfied_mods.push_back(*last_mod_spec);
+	}
 }

src/content/mod_configuration.h

@@ -87,6 +87,9 @@ public:
 	void checkConflictsAndDeps();
 
 private:
+	std::string m_first_mod; // "" <=> no mod
+	std::string m_last_mod; // "" <=> no mod
+
 	std::vector<ModSpec> m_sorted_mods;
 
 	/**

src/content/subgames.cpp

@@ -94,6 +94,50 @@ std::string getSubgamePathEnv()
 	return "";
 }
 
+static SubgameSpec getSubgameSpec(const std::string &game_id,
+		const std::string &game_path,
+		const std::unordered_map<std::string, std::string> &mods_paths,
+		const std::string &menuicon_path)
+{
+	const auto gamemods_path = game_path + DIR_DELIM + "mods";
+	// Get meta
+	const std::string conf_path = game_path + DIR_DELIM + "game.conf";
+	Settings conf;
+	conf.readConfigFile(conf_path.c_str());
+
+	std::string game_title;
+	if (conf.exists("title"))
+		game_title = conf.get("title");
+	else if (conf.exists("name"))
+		game_title = conf.get("name");
+	else
+		game_title = game_id;
+
+	std::string game_author;
+	if (conf.exists("author"))
+		game_author = conf.get("author");
+
+	int game_release = 0;
+	if (conf.exists("release"))
+		game_release = conf.getS32("release");
+
+	std::string first_mod;
+	if (conf.exists("first_mod"))
+		first_mod = conf.get("first_mod");
+
+	std::string last_mod;
+	if (conf.exists("last_mod"))
+		last_mod = conf.get("last_mod");
+
+	SubgameSpec spec(game_id, game_path, gamemods_path, mods_paths, game_title,
+			menuicon_path, game_author, game_release, first_mod, last_mod);
+
+	if (conf.exists("name") && !conf.exists("title"))
+		spec.deprecation_msgs.push_back("\"name\" setting in game.conf is deprecated, please use \"title\" instead");
+
+	return spec;
+}
+
 SubgameSpec findSubgame(const std::string &id)
 {
 	if (id.empty())
@@ -137,8 +181,6 @@ SubgameSpec findSubgame(const std::string &id)
 	if (game_path.empty())
 		return SubgameSpec();
 
-	std::string gamemod_path = game_path + DIR_DELIM + "mods";
-
 	// Find mod directories
 	std::unordered_map<std::string, std::string> mods_paths;
 	mods_paths["mods"] = user + DIR_DELIM + "mods";
@@ -149,40 +191,13 @@ SubgameSpec findSubgame(const std::string &id)
 		mods_paths[fs::AbsolutePath(mod_path)] = mod_path;
 	}
 
-	// Get meta
-	std::string conf_path = game_path + DIR_DELIM + "game.conf";
-	Settings conf;
-	conf.readConfigFile(conf_path.c_str());
-
-	std::string game_title;
-	if (conf.exists("title"))
-		game_title = conf.get("title");
-	else if (conf.exists("name"))
-		game_title = conf.get("name");
-	else
-		game_title = id;
-
-	std::string game_author;
-	if (conf.exists("author"))
-		game_author = conf.get("author");
-
-	int game_release = 0;
-	if (conf.exists("release"))
-		game_release = conf.getS32("release");
-
 	std::string menuicon_path;
 #ifndef SERVER
 	menuicon_path = getImagePath(
 			game_path + DIR_DELIM + "menu" + DIR_DELIM + "icon.png");
 #endif
 
-	SubgameSpec spec(id, game_path, gamemod_path, mods_paths, game_title,
+	return getSubgameSpec(id, game_path, mods_paths, menuicon_path);
-			menuicon_path, game_author, game_release);
-
-	if (conf.exists("name") && !conf.exists("title"))
-		spec.deprecation_msgs.push_back("\"name\" setting in game.conf is deprecated, please use \"title\" instead");
-
-	return spec;
 }
 
 SubgameSpec findWorldSubgame(const std::string &world_path)
@@ -190,25 +205,8 @@ SubgameSpec findWorldSubgame(const std::string &world_path)
 	std::string world_gameid = getWorldGameId(world_path, true);
 	// See if world contains an embedded game; if so, use it.
 	std::string world_gamepath = world_path + DIR_DELIM + "game";
-	if (fs::PathExists(world_gamepath)) {
+	if (fs::PathExists(world_gamepath))
-		SubgameSpec gamespec;
+		return getSubgameSpec(world_gameid, world_gamepath, {}, "");
-		gamespec.id = world_gameid;
-		gamespec.path = world_gamepath;
-		gamespec.gamemods_path = world_gamepath + DIR_DELIM + "mods";
-
-		Settings conf;
-		std::string conf_path = world_gamepath + DIR_DELIM + "game.conf";
-		conf.readConfigFile(conf_path.c_str());
-
-		if (conf.exists("title"))
-			gamespec.title = conf.get("title");
-		else if (conf.exists("name"))
-			gamespec.title = conf.get("name");
-		else
-			gamespec.title = world_gameid;
-
-		return gamespec;
-	}
 	return findSubgame(world_gameid);
 }
 

src/content/subgames.h

@@ -32,6 +32,8 @@ struct SubgameSpec
 	std::string title;
 	std::string author;
 	int release;
+	std::string first_mod; // "" <=> no mod
+	std::string last_mod; // "" <=> no mod
 	std::string path;
 	std::string gamemods_path;
 
@@ -49,10 +51,16 @@ struct SubgameSpec
 			const std::unordered_map<std::string, std::string> &addon_mods_paths = {},
 			const std::string &title = "",
 			const std::string &menuicon_path = "",
-			const std::string &author = "", int release = 0) :
+			const std::string &author = "", int release = 0,
+			const std::string &first_mod = "",
+			const std::string &last_mod = "") :
 			id(id),
-			title(title), author(author), release(release), path(path),
+			title(title), author(author), release(release),
-			gamemods_path(gamemods_path), addon_mods_paths(addon_mods_paths),
+			first_mod(first_mod),
+			last_mod(last_mod),
+			path(path),
+			gamemods_path(gamemods_path),
+			addon_mods_paths(addon_mods_paths),
 			menuicon_path(menuicon_path)
 	{
 	}

src/unittest/test_servermodmanager.cpp

@@ -121,7 +121,8 @@ void TestServerModManager::testGetMods()
 {
 	ServerModManager sm(m_worlddir);
 	const auto &mods = sm.getMods();
-	UASSERTEQ(bool, mods.empty(), false);
+	// `ls ./games/devtest/mods | wc -l` + 1 (test mod)
+	UASSERTEQ(std::size_t, mods.size(), 31 + 1);
 
 	// Ensure we found basenodes mod (part of devtest)
 	// and test_mod (for testing MINETEST_MOD_PATH).
@@ -139,6 +140,9 @@ void TestServerModManager::testGetMods()
 
 	UASSERTEQ(bool, default_found, true);
 	UASSERTEQ(bool, test_mod_found, true);
+
+	UASSERT(mods.front().name == "first_mod");
+	UASSERT(mods.back().name == "last_mod");
 }
 
 void TestServerModManager::testGetModspec()