Lua解释器无法找到json模块问题求助

我通过luarocks install --local json-lua安装了json-lua模块，执行eval $(luarocks path)配置路径后，在Lua 5.3.6解释器中执行require("json")时仍提示找不到该模块。操作流程如下：

(base) user@USR-0318:~/.luarocks/lib
 $ luarocks list

Rocks installed for Lua 5.1
---------------------------

busted
   2.2.0-1 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   2.2.0-1 (installed) - /usr/local/lib/luarocks/rocks-5.1

dkjson
   2.8-1 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   2.8-1 (installed) - /usr/local/lib/luarocks/rocks-5.1

json-lua
   0.1-4 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1

lua-term
   0.8-1 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   0.8-1 (installed) - /usr/local/lib/luarocks/rocks-5.1

lua_cliargs
   3.0-2 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   3.0-2 (installed) - /usr/local/lib/luarocks/rocks-5.1

luafilesystem
   1.8.0-1 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   1.8.0-1 (installed) - /usr/local/lib/luarocks/rocks-5.1

luassert
   1.9.0-1 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   1.9.0-1 (installed) - /usr/local/lib/luarocks/rocks-5.1

luasystem
   0.5.1-1 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   0.5.1-1 (installed) - /usr/local/lib/luarocks/rocks-5.1

mediator_lua
   1.1.2-0 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   1.1.2-0 (installed) - /usr/local/lib/luarocks/rocks-5.1

penlight
   1.14.0-2 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   1.14.0-2 (installed) - /usr/local/lib/luarocks/rocks-5.1

say
   1.4.1-3 (installed) - /home/user/.luarocks/lib/luarocks/rocks-5.1
   1.4.1-3 (installed) - /usr/local/lib/luarocks/rocks-5.1

(base) user@USR-0318:~/.luarocks/lib
 $ eval $(luarocks path)
(base) user@USR-0318:~/.luarocks/lib
 $ echo $LUA_PATH
/usr/local/share/lua/5.1/?.lua;./?.lua;/usr/local/share/lua/5.1/?/init.lua;/usr/local/lib/lua/5.1/?.lua;/usr/local/lib/lua/5.1/?/init.lua;/usr/share/lua/5.1/?.lua;/usr/share/lua/5.1/?/init.lua;/home/user/.luarocks/share/lua/5.1/?.lua;/home/user/.luarocks/share/lua/5.1/?/init.lua
(base) user@USR-0318:~/.luarocks/lib
 $ lua
Lua 5.3.6  Copyright (C) 1994-2020 Lua.org, PUC-Rio
> require("json")
stdin:1: module 'json' not found:
        no field package.preload['json']
        no file '/usr/local/share/lua/5.1/json.lua'
        no file './json.lua'
        no file '/usr/local/share/lua/5.1/json/init.lua'
        no file '/usr/local/lib/lua/5.1/json.lua'
        no file '/usr/local/lib/lua/5.1/json/init.lua'
        no file '/usr/share/lua/5.1/json.lua'
        no file '/usr/share/lua/5.1/json/init.lua'
        no file '/home/user/.luarocks/share/lua/5.1/json.lua'
        no file '/home/user/.luarocks/share/lua/5.1/json/init.lua'
        no file './json.so'
        no file '/usr/local/lib/lua/5.1/json.so'
        no file '/usr/lib/x86_64-linux-gnu/lua/5.1/json.so'
        no file '/usr/lib/lua/5.1/json.so'
        no file '/usr/local/lib/lua/5.1/loadall.so'
        no file '/home/user/.luarocks/lib/lua/5.1/json.so'
stack traceback:
        [C]: in function 'require'
        stdin:1: in main chunk
        [C]: in ?
>

我发现json库安装在.luarocks/lib目录下，但执行luarocks path后该目录并未加入LUA_PATH，想知道自己哪里操作有误，该如何解决？

核心问题：Lua版本不匹配 #

从luarocks list输出能看到，所有模块都是安装给Lua 5.1的，但你实际运行的是Lua 5.3.6。Luarocks默认绑定系统中的Lua 5.1，导致安装的模块无法被Lua 5.3识别。

解决步骤 #

1. 安装对应Lua 5.3的Luarocks #

如果系统没有针对Lua 5.3的Luarocks，可通过以下方式安装：

• 源码编译（以Luarocks 3.9.2为例）：

  wget https://luarocks.org/releases/luarocks-3.9.2.tar.gz
  tar zxf luarocks-3.9.2.tar.gz
  cd luarocks-3.9.2
  ./configure --lua-version=5.3 --with-lua-include=/usr/include/lua5.3 --with-lua-lib=/usr/lib/x86_64-linux-gnu
  make && sudo make install
  

• 包管理器安装（Debian/Ubuntu）：

  sudo apt install luarocks5.3
  

2. 用Lua 5.3的Luarocks安装json-lua #

使用对应版本的Luarocks命令（编译安装可能仍为luarocks，包管理器安装则为luarocks5.3）：

luarocks5.3 install --local json-lua

3. 配置Lua 5.3的模块路径 #

执行对应版本的Luarocks路径命令配置环境变量：

eval $(luarocks5.3 path --local)

之后运行lua5.3，执行require("json")即可正常加载模块。

临时 workaround（不推荐长期使用） #

若不想重新安装Luarocks，可手动将Lua 5.1的模块路径添加到Lua 5.3的package.path中：

-- 在Lua 5.3解释器中执行
package.path = package.path .. ";/home/user/.luarocks/share/lua/5.1/?.lua;/home/user/.luarocks/share/lua/5.1/?/init.lua"
require("json")

但这种方式可能因Lua版本差异引发模块兼容性问题，优先推荐使用对应版本的Luarocks安装模块。

内容的提问来源于stack exchange，提问作者glades