feat(lua): add proper support of luv threads

runtime/lua/vim/_load_package.lua

@@ -0,0 +1,48 @@
+-- prevents luacheck from making lints for setting things on vim
+local vim = assert(vim)
+
+local pathtrails = {}
+vim._so_trails = {}
+for s in  (package.cpath..';'):gmatch('[^;]*;') do
+    s = s:sub(1, -2)  -- Strip trailing semicolon
+  -- Find out path patterns. pathtrail should contain something like
+  -- /?.so, \?.dll. This allows not to bother determining what correct
+  -- suffixes are.
+  local pathtrail = s:match('[/\\][^/\\]*%?.*$')
+  if pathtrail and not pathtrails[pathtrail] then
+    pathtrails[pathtrail] = true
+    table.insert(vim._so_trails, pathtrail)
+  end
+end
+
+function vim._load_package(name)
+  local basename = name:gsub('%.', '/')
+  local paths = {"lua/"..basename..".lua", "lua/"..basename.."/init.lua"}
+  local found = vim.api.nvim__get_runtime(paths, false, {is_lua=true})
+  if #found > 0 then
+    local f, err = loadfile(found[1])
+    return f or error(err)
+  end
+
+  local so_paths = {}
+  for _,trail in ipairs(vim._so_trails) do
+    local path = "lua"..trail:gsub('?', basename) -- so_trails contains a leading slash
+    table.insert(so_paths, path)
+  end
+
+  found = vim.api.nvim__get_runtime(so_paths, false, {is_lua=true})
+  if #found > 0 then
+    -- Making function name in Lua 5.1 (see src/loadlib.c:mkfuncname) is
+    -- a) strip prefix up to and including the first dash, if any
+    -- b) replace all dots by underscores
+    -- c) prepend "luaopen_"
+    -- So "foo-bar.baz" should result in "luaopen_bar_baz"
+    local dash = name:find("-", 1, true)
+    local modname = dash and name:sub(dash + 1) or name
+    local f, err = package.loadlib(found[1], "luaopen_"..modname:gsub("%.", "_"))
+    return f or error(err)
+  end
+  return nil
+end
+
+table.insert(package.loaders, 1, vim._load_package)

src/cjson/lua_cjson.c

@@ -776,7 +776,7 @@ static void json_append_data(lua_State *l, json_config_t *cfg,
 
         if (has_metatable) {
 
-          nlua_pushref(l, nlua_empty_dict_ref);
+          nlua_pushref(l, nlua_get_empty_dict_ref(l));
           if (lua_rawequal(l, -2, -1)) {
             as_empty_dict = true;
           } else {
@@ -822,7 +822,7 @@ static void json_append_data(lua_State *l, json_config_t *cfg,
         }
         break;
     case LUA_TUSERDATA:
-        nlua_pushref(l, nlua_nil_ref);
+        nlua_pushref(l, nlua_get_nil_ref(l));
         bool is_nil = lua_rawequal(l, -2, -1);
         lua_pop(l, 1);
         if (is_nil) {
@@ -1285,7 +1285,7 @@ static void json_parse_object_context(lua_State *l, json_parse_t *json)
 
     /* Handle empty objects */
     if (token.type == T_OBJ_END) {
-        nlua_pushref(l, nlua_empty_dict_ref); \
+        nlua_pushref(l, nlua_get_empty_dict_ref(l)); \
         lua_setmetatable(l, -2); \
         json_decode_ascend(json);
         return;
@@ -1392,7 +1392,7 @@ static void json_process_value(lua_State *l, json_parse_t *json,
         if (use_luanil) {
             lua_pushnil(l);
         } else {
-            nlua_pushref(l, nlua_nil_ref);
+            nlua_pushref(l, nlua_get_nil_ref(l));
         }
         break;;
     default:
@@ -1549,7 +1549,15 @@ int lua_cjson_new(lua_State *l)
     };
 
     /* Initialise number conversions */
-    fpconv_init();
+    lua_getfield(l, LUA_REGISTRYINDEX, "nvim.thread");
+    bool is_thread = lua_toboolean(l, -1);
+    lua_pop(l, 1);
+
+    // Since fpconv_init does not need to be called multiple times and is not
+    // thread safe, it should only be called in the main thread.
+    if (!is_thread) {
+        fpconv_init();
+    }
 
     /* Test if array metatables are in registry */
     lua_pushlightuserdata(l, json_lightudata_mask(&json_empty_array));
@@ -1582,7 +1590,7 @@ int lua_cjson_new(lua_State *l)
     compat_luaL_setfuncs(l, reg, 1);
 
     /* Set cjson.null */
-    nlua_pushref(l, nlua_nil_ref);
+    nlua_pushref(l, nlua_get_nil_ref(l));
     lua_setfield(l, -2, "null");
 
     /* Set cjson.empty_array_mt */

src/nvim/CMakeLists.txt

@@ -63,6 +63,7 @@ set(LUA_INSPECT_MODULE_SOURCE ${PROJECT_SOURCE_DIR}/runtime/lua/vim/inspect.lua)
 set(LUA_F_MODULE_SOURCE ${PROJECT_SOURCE_DIR}/runtime/lua/vim/F.lua)
 set(LUA_META_MODULE_SOURCE ${PROJECT_SOURCE_DIR}/runtime/lua/vim/_meta.lua)
 set(LUA_FILETYPE_MODULE_SOURCE ${PROJECT_SOURCE_DIR}/runtime/lua/vim/filetype.lua)
+set(LUA_LOAD_PACKAGE_MODULE_SOURCE ${PROJECT_SOURCE_DIR}/runtime/lua/vim/_load_package.lua)
 set(CHAR_BLOB_GENERATOR ${GENERATOR_DIR}/gen_char_blob.lua)
 set(LINT_SUPPRESS_FILE ${PROJECT_BINARY_DIR}/errors.json)
 set(LINT_SUPPRESS_URL_BASE "https://raw.githubusercontent.com/neovim/doc/gh-pages/reports/clint")
@@ -336,6 +337,7 @@ add_custom_command(
       ${LUA_F_MODULE_SOURCE} lua_F_module
       ${LUA_META_MODULE_SOURCE} lua_meta_module
       ${LUA_FILETYPE_MODULE_SOURCE} lua_filetype_module
+      ${LUA_LOAD_PACKAGE_MODULE_SOURCE} lua_load_package_module
   DEPENDS
     ${CHAR_BLOB_GENERATOR}
     ${LUA_VIM_MODULE_SOURCE}
@@ -344,6 +346,7 @@ add_custom_command(
     ${LUA_F_MODULE_SOURCE}
     ${LUA_META_MODULE_SOURCE}
     ${LUA_FILETYPE_MODULE_SOURCE}
+    ${LUA_LOAD_PACKAGE_MODULE_SOURCE}
   VERBATIM
 )
 

src/nvim/api/vim.c

@@ -1955,7 +1955,7 @@ Dictionary nvim__stats(void)
   Dictionary rv = ARRAY_DICT_INIT;
   PUT(rv, "fsync", INTEGER_OBJ(g_stats.fsync));
   PUT(rv, "redraw", INTEGER_OBJ(g_stats.redraw));
-  PUT(rv, "lua_refcount", INTEGER_OBJ(nlua_refcount));
+  PUT(rv, "lua_refcount", INTEGER_OBJ(nlua_get_global_ref_count()));
   return rv;
 }
 

src/nvim/lua/converter.c

@@ -156,7 +156,7 @@ static LuaTableProps nlua_traverse_table(lua_State *const lstate)
             && ret.string_keys_num == 0)) {
       ret.type = kObjectTypeArray;
       if (tsize == 0 && lua_getmetatable(lstate, -1)) {
-        nlua_pushref(lstate, nlua_empty_dict_ref);
+        nlua_pushref(lstate, nlua_get_empty_dict_ref(lstate));
         if (lua_rawequal(lstate, -2, -1)) {
           ret.type = kObjectTypeDictionary;
         }
@@ -401,7 +401,7 @@ bool nlua_pop_typval(lua_State *lstate, typval_T *ret_tv)
     }
     case LUA_TUSERDATA: {
       // TODO(bfredl): check mt.__call and convert to function?
-      nlua_pushref(lstate, nlua_nil_ref);
+      nlua_pushref(lstate, nlua_get_nil_ref(lstate));
       bool is_nil = lua_rawequal(lstate, -2, -1);
       lua_pop(lstate, 1);
       if (is_nil) {
@@ -445,7 +445,7 @@ static bool typval_conv_special = false;
     if (typval_conv_special) { \
       lua_pushnil(lstate); \
     } else { \
-      nlua_pushref(lstate, nlua_nil_ref); \
+      nlua_pushref(lstate, nlua_get_nil_ref(lstate)); \
     } \
   } while (0)
 
@@ -495,7 +495,7 @@ static bool typval_conv_special = false;
       nlua_create_typed_table(lstate, 0, 0, kObjectTypeDictionary); \
     } else { \
       lua_createtable(lstate, 0, 0); \
-      nlua_pushref(lstate, nlua_empty_dict_ref); \
+      nlua_pushref(lstate, nlua_get_empty_dict_ref(lstate)); \
       lua_setmetatable(lstate, -2); \
     } \
   } while (0)
@@ -734,7 +734,7 @@ void nlua_push_Dictionary(lua_State *lstate, const Dictionary dict, bool special
   } else {
     lua_createtable(lstate, 0, (int)dict.size);
     if (dict.size == 0 && !special) {
-      nlua_pushref(lstate, nlua_empty_dict_ref);
+      nlua_pushref(lstate, nlua_get_empty_dict_ref(lstate));
       lua_setmetatable(lstate, -2);
     }
   }
@@ -782,7 +782,7 @@ void nlua_push_Object(lua_State *lstate, const Object obj, bool special)
     if (special) {
       lua_pushnil(lstate);
     } else {
-      nlua_pushref(lstate, nlua_nil_ref);
+      nlua_pushref(lstate, nlua_get_nil_ref(lstate));
     }
     break;
   case kObjectTypeLuaRef: {
@@ -1206,7 +1206,7 @@ Object nlua_pop_Object(lua_State *const lstate, bool ref, Error *const err)
       break;
 
     case LUA_TUSERDATA: {
-      nlua_pushref(lstate, nlua_nil_ref);
+      nlua_pushref(lstate, nlua_get_nil_ref(lstate));
       bool is_nil = lua_rawequal(lstate, -2, -1);
       lua_pop(lstate, 1);
       if (is_nil) {