Migrating from Geode v3.x to v4.0

Changes to Result

Link to the full docs

• Result type has been rewritten from scratch, and it is now shared with many parts of the Geode codebase (Geode itself, TulipHook and matjson).
• Many methods removed or renamed:
  • value() -> unwrap()
  • expect(str, fmt args...) -> Use mapErr along with fmt::format
  • Snake case methods renamed to camel case
• Universal GEODE_UNWRAP(res) and GEODE_UNWRAP_INTO(value, res) macros
  • These macros were already previously available, but this is just a reminder that they can help a lot when dealing with results.

  Result<std::string> addValues(matjson::Value json) {
     // Value::asInt() returns a Result<int>
     GEODE_UNWRAP_INTO(int a, json["a"].asInt());
     GEODE_UNWRAP_INTO(int b, json["b"].asInt());
     // must wrap return value with Ok
     return Ok(fmt::format("sum is {}", a + b));
  }
  

  • If you only ever expect to build your code with clang, you can use the GEODE_UNWRAP macro like so, for convenience:

  Result<int> getInt();
  
  Result<int> foo(int extra) {
      // This will not compile on MSVC
      int value = GEODE_UNWRAP(getInt()) + extra;
      return Ok(value);
  }
  

Changes to the Geode Settings API

• Settings v2 has been removed, V3 suffix from classes are now aliased
• Most SettingV3 code should work fine, with the exception of some Result usages:

static Result<std::shared_ptr<MyCustomSettingV3>> parse(std::string const&, std::string const&, matjson::Value const& json) {
   auto res = std::make_shared<MyCustomSettingV3>();
   auto root = checkJson(json, "MyCustomSettingV3");
   // ... some code here ...
   return root.ok(res);
}
// should now be:
//                            ↓ here
static Result<std::shared_ptr<SettingV3>> parse(std::string const&, std::string const&, matjson::Value const& json) {
   auto res = std::make_shared<MyCustomSettingV3>();
   auto root = checkJson(json, "MyCustomSettingV3");
   // ... some code here ...
   //             ↓ here
   return root.ok(std::static_pointer_cast<SettingV3>(res));
}

Changes to utils::MiniFunction

• Removed, use std::function now

Changes to geode::Layout

• No longer in cocos2d namespace
  • Can now be found in Geode/ui/Layout.hpp

Changes to getChildOfType

• Deprecated in 3.9.0, and now removed, use CCNode::getChildByType<T>(int index) instead:
• getChildOfType<CCLayer>(node, 1) -> node->getChildByType<CCLayer>(1)
• You can use this regex pattern to quickly find and replace:
  • getChildOfType<(.+?)>\((.+?),\s*(.+?)\) and replace with $2->getChildByType<$1>($3)

Changes to matjson

Link to the full docs

• Entire library rewritten to use geode::Result
  • See result section for tips on how to use Geode’s Result class
• Methods are now camel case to fit with rest of Geode’s codebase
  • is_string -> isString
  • as_string -> asString
  • etc..
• matjson::Object has been removed, now you can just iterate directly off a Value (same for arrays!)

  matjson::Value someObject = ...;
  for (auto& [key, value] : someObject) {
      log::debug("{}: {}", key, value);
  }
  
  matjson::Value someArray = ...;
  for (auto& value : someArray) {
      log::debug("{}", value);
  }
  

• Use matjson::makeObject for making objects inline now:

  matjson::Value obj = matjson::makeObject({
      { "key", 123 },
      { "another-key": "another value!" }
  });
  

• Accessing missing properties with Value::operator[] will now return a null value instead of throwing an exception
• Serialization methods have been changed:
  • T from_json(matjson::Value const&) -> Result<T> fromJson(matjson::Value const&)
    • Make sure to return a Result! much of the code relies on fromJson returning a Result.
  • matjson::Value to_json(T const& value) -> matjson::Value toJson(T const& value)
  • is_json is no longer used, instead just return an error in fromJson
• bool Value::is<T>() removed
• #include <matjson/stl_serialize.hpp> -> #include <matjson/std.hpp>
• Added new experimental <matjson/reflect.hpp> header, uses qlibs/reflect to (de)serialize aggregate structs
  • Behavior might change in the future, so use with caution

Changes to JsonChecker / JsonExpectedValue

• The JsonChecker class was previously marked deprecated, and is now removed. Now you should move to using JsonExpectedValue instead

auto checker = JsonChecker(json);
auto root = checker.root("[file.json]").obj();

// ... code

if (checker.isError()) {
    return Err(checker.getError());
}

is now

auto root = checkJson(json, "[file.json]")

// ... code

GEODE_UNWRAP(root.ok());

• JsonChecker::has has different behavior to JsonExpectedValue::has, use JsonExpectedValue::hasNullable to keep old behavior with null values