Lua Script validation

[Iurysab]

Hi! First of all, thank you for the sol2 library. It is incredibly useful and robust.

I have created several "Lua classes" using new_usertype. These classes have specific functions and attributes. My goal is to validate a user's Lua script to ensure it is correct regarding both syntax (Lua grammar) and semantics (checking if the called methods/attributes actually exist in my C++ bindings).

When I use lua.load_file (or lua.load), it only validates the Lua syntax. If the script contains a call to a non-existent method (e.g., a typo like myObj:mve() instead of myObj:move()), load considers it valid. The error only pops up at runtime when I actually execute the script.

Is there a recommended pattern or feature in sol2 to perform a "Dry Run" or a "Safety Check" that detects these binding errors (like "attempt to call method 'x' a nil value") without executing the script?

I am currently implementing a "Dry Run" flag in my C++ classes to bypass logic during validation, but I was wondering if sol2 has a more native or elegant solution for introspecting the script against the registered usertypes.

Example:

// Setup
lua.new_usertype<Robot>("Robot", "move", &Robot::move);

// Script with a typo ("mve" instead of "move")
std::string bad_script = "local r = Robot.new(); r:mve(10);";

// This passes (returns valid), which is expected for Lua
auto result = lua.load(bad_script); 

// I want to catch the error here, without running "real" game logic
if (result.valid()) {
    // How to validate that 'mve' does not exist safely?
}

Thanks in advance for any help!

[Nerixyz]

You probably want static analysis/type checking. Determining that all calls are correct is impossible to do generally. Static analysis usually relies on annotations and/or supplementary metadata files. This isn't possible with sol2, you'll need external tools.
Here's a small collection of them (most are editor plugins, but you can probably get them to run a typecheck pass):

• LuaLS
• EmmyLua
• EmmyLua Analyzer Rust