Add set_array_metatable option to json decoder

Author: khvzak

src/json.rs

@@ -3,8 +3,8 @@ use std::sync::Arc;
 
 use mlua::{
     AnyUserData, Error as LuaError, ExternalResult, Function, Integer as LuaInteger, IntoLuaMulti, Lua,
-    LuaSerdeExt, MetaMethod, MultiValue, Result, String as LuaString, Table, UserData, UserDataMethods,
-    UserDataRefMut, Value,
+    LuaSerdeExt, MetaMethod, MultiValue, Result, SerializeOptions, String as LuaString, Table, UserData,
+    UserDataMethods, UserDataRefMut, Value,
 };
 use ouroboros::self_referencing;
 use serde::{Serialize, Serializer};
@@ -188,9 +188,15 @@ struct LuaJsonMapIter {
     iter: serde_json::map::Iter<'this>,
 }
 
-fn decode(lua: &Lua, data: StringOrBytes) -> Result<StdResult<Value, String>> {
+fn decode(lua: &Lua, (data, opts): (StringOrBytes, Option<Table>)) -> Result<StdResult<Value, String>> {
+    let opts = opts.as_ref();
+    let mut options = SerializeOptions::new();
+    if let Some(enabled) = opts.and_then(|t| t.get::<bool>("set_array_metatable").ok()) {
+        options = options.set_array_metatable(enabled);
+    }
+
     let json: serde_json::Value = lua_try!(serde_json::from_slice(&data.as_bytes_deref()).into_lua_err());
-    Ok(Ok(lua.to_value(&json)?))
+    Ok(Ok(lua.to_value_with(&json, options)?))
 }
 
 fn decode_native(lua: &Lua, data: StringOrBytes) -> Result<StdResult<Value, String>> {

tests/lua/json_tests.lua

@@ -31,6 +31,12 @@ testing:test("decode", function(t)
     value, err = json.decode("{a:1}")
     t.assert_eq(value, nil)
     t.assert(err:find("key must be a string"), "unexpected error message: " .. err)
+
+    -- No array metatable by default
+    value, err = json.decode("[1,2,3]", { set_array_metatable = false })
+    t.assert_eq(err, nil)
+    t.assert_eq(type(value), "table", "value is not a table")
+    t.assert_eq(getmetatable(value), nil, "array metatable is set")
 end)
 
 -- Test decode to native object