Expose client version information in non-debug builds (#15708)

Co-authored-by: SmallJoker <SmallJoker@users.noreply.github.com>
Co-authored-by: Lars Mueller <appgurulars@gmx.de>
Co-authored-by: sfan5 <sfan5@live.de>

builtin/game/misc_s.lua

@@ -112,3 +112,25 @@ if core.set_push_moveresult1 then
 	end)
 	core.set_push_moveresult1 = nil
 end
+
+-- Protocol version table
+-- see also src/network/networkprotocol.cpp
+core.protocol_versions = {
+	["5.0.0"] = 37,
+	["5.1.0"] = 38,
+	["5.2.0"] = 39,
+	["5.3.0"] = 39,
+	["5.4.0"] = 39,
+	["5.5.0"] = 40,
+	["5.6.0"] = 41,
+	["5.7.0"] = 42,
+	["5.8.0"] = 43,
+	["5.9.0"] = 44,
+	["5.9.1"] = 45,
+	["5.10.0"] = 46,
+	["5.11.0"] = 47,
+}
+
+setmetatable(core.protocol_versions, {__newindex = function()
+	error("core.protocol_versions is read-only")
+end})

doc/lua_api.md

@@ -5578,7 +5578,7 @@ Utilities
     * It's possible that multiple Luanti instances are running at the same
       time, which may lead to corruption if you are not careful.
 * `core.is_singleplayer()`
-* `core.features`: Table containing API feature flags
+* `core.features`: Table containing *server-side* API feature flags
 
   ```lua
   {
@@ -5693,6 +5693,7 @@ Utilities
   ```
 
 * `core.has_feature(arg)`: returns `boolean, missing_features`
+    * checks for *server-side* feature availability
     * `arg`: string or table in format `{foo=true, bar=true}`
     * `missing_features`: `{foo=true, bar=true}`
 * `core.get_player_information(player_name)`: Table containing information
@@ -5714,17 +5715,40 @@ Utilities
       min_jitter = 0.01,         -- minimum packet time jitter
       max_jitter = 0.5,          -- maximum packet time jitter
       avg_jitter = 0.03,         -- average packet time jitter
+
+      -- The version information is provided by the client and may be spoofed
+      -- or inconsistent in engine forks. You must not use this for checking
+      -- feature availability of clients. Instead, do use the fields
+      -- `protocol_version` and `formspec_version` where it matters.
+      -- Use `core.protocol_versions` to map Luanti versions to protocol versions.
+      -- This version string is only suitable for analysis purposes.
+      version_string = "0.4.9-git",   -- full version string
+
       -- the following information is available in a debug build only!!!
       -- DO NOT USE IN MODS
       --serialization_version = 26,     -- serialization version used by client
       --major = 0,                      -- major version number
       --minor = 4,                      -- minor version number
       --patch = 10,                     -- patch version number
-      --version_string = "0.4.9-git",   -- full version string
       --state = "Active"                -- current client state
   }
   ```
 
+* `core.protocol_versions`:
+  * Table mapping Luanti versions to corresponding protocol versions for modder convenience.
+  * For example, to check whether a client has at least the feature set
+    of Luanti 5.8.0 or newer, you could do:
+    `core.get_player_information(player_name).protocol_version >= core.protocol_versions["5.8.0"]`
+  * (available since 5.11)
+
+  ```lua
+  {
+      [version string] = protocol version at time of release
+      -- every major and minor version has an entry
+      -- patch versions only for the first release whose protocol version is not already present in the table
+  }
+  ```
+
 * `core.get_player_window_information(player_name)`:
 
   ```lua

games/devtest/.luacheckrc

@@ -31,7 +31,7 @@ read_globals = {
 	"PcgRandom",
 
 	string = {fields = {"split", "trim"}},
-	table  = {fields = {"copy", "getn", "indexof", "insert_all"}},
+	table  = {fields = {"copy", "getn", "indexof", "insert_all", "key_value_swap"}},
 	math   = {fields = {"hypot", "round"}},
 }
 

games/devtest/mods/unittests/init.lua

@@ -192,7 +192,7 @@ dofile(modpath .. "/crafting.lua")
 dofile(modpath .. "/itemdescription.lua")
 dofile(modpath .. "/async_env.lua")
 dofile(modpath .. "/entity.lua")
-dofile(modpath .. "/get_version.lua")
+dofile(modpath .. "/version.lua")
 dofile(modpath .. "/itemstack_equals.lua")
 dofile(modpath .. "/content_ids.lua")
 dofile(modpath .. "/metadata.lua")

games/devtest/mods/unittests/version.lua

@@ -0,0 +1,40 @@
+unittests.register("test_get_version", function()
+	local version = core.get_version()
+	assert(type(version) == "table")
+	assert(type(version.project) == "string")
+	assert(type(version.string) == "string")
+	assert(type(version.proto_min) == "number")
+	assert(type(version.proto_max) == "number")
+	assert(version.proto_max >= version.proto_min)
+	assert(type(version.is_dev) == "boolean")
+	if version.is_dev then
+		assert(type(version.hash) == "string")
+	else
+		assert(version.hash == nil)
+	end
+end)
+
+unittests.register("test_protocol_version", function(player)
+	local info = core.get_player_information(player:get_player_name())
+
+	local maxver = 0
+	for _, v in pairs(core.protocol_versions) do
+		maxver = math.max(maxver, v)
+	end
+	assert(maxver > 0) -- table must contain something valid
+
+	-- If the client is older than a known version then it's pointless.
+	if info.protocol_version < maxver then
+		core.log("warning", "test_protocol_version: client is outdated, skipping test!")
+		return
+	end
+	local info_server = core.get_version()
+	if info.version_string ~= (info_server.hash or info_server.string) then
+		core.log("warning", "test_protocol_version: client is not the same version. False-positive possible.")
+	end
+
+	-- The protocol version the client and server agreed on must exist in the table.
+	local match = table.key_value_swap(core.protocol_versions)[info.protocol_version]
+	assert(match ~= nil)
+	print(string.format("client proto matched: %s sent: %s", match, info.version_string))
+end, {player = true})

src/network/networkprotocol.cpp

@@ -64,6 +64,7 @@
 		[scheduled bump for 5.11.0]
 */
 
+// Note: Also update core.protocol_versions in builtin when bumping
 const u16 LATEST_PROTOCOL_VERSION = 47;
 
 // See also formspec [Version History] in doc/lua_api.md

src/script/lua_api/l_server.cpp

@@ -239,6 +239,10 @@ int ModApiServer::l_get_player_information(lua_State *L)
 	lua_pushstring(L, info.lang_code.c_str());
 	lua_settable(L, table);
 
+	lua_pushstring(L, "version_string");
+	lua_pushstring(L, info.vers_string.c_str());
+	lua_settable(L, table);
+
 #ifndef NDEBUG
 	lua_pushstring(L,"serialization_version");
 	lua_pushnumber(L, info.ser_vers);
@@ -256,10 +260,6 @@ int ModApiServer::l_get_player_information(lua_State *L)
 	lua_pushnumber(L, info.patch);
 	lua_settable(L, table);
 
-	lua_pushstring(L,"version_string");
-	lua_pushstring(L, info.vers_string.c_str());
-	lua_settable(L, table);
-
 	lua_pushstring(L,"state");
 	lua_pushstring(L, ClientInterface::state2Name(info.state).c_str());
 	lua_settable(L, table);