Redirect

Danger

Redirects are not recommended as they cause hard conflicts with any other mod attempting to mixin into the same location. They can usually be replaced by either a WrapOperation or WrapWithCondition.

Redirect lets you redirect a method call to a different method.

Say we had the following:

public void foo(int param) {
    int a = getInt(param);
    String b = getString(param);
    boolean c = getBool(param);
    doSomething(a, b, c);
}

If we want to change the doSomething to something else, wrap the original call in a check, or simply skip the call altogether, we can do that as such:

@Redirect(method = "foo", at = @At(value = "INVOKE", target = "doSomething(ILjava/lang/String;Z)V"))
private void wrapSomething(Foo instance, int a, String b, boolean c, Operation<Void> original) {
    if (ModConfig.doSomethingElse) {
        return doSomethingElse(a, b, c); // new method
    } else if (ModConfig.doOriginal) {
        return doSomething(a, b, c); // original method, but conditionally wrapped
    } else {
        // No-op (the original method call is skipped entirely)
    }
}

Resulting in:

public void foo(int param) {
    int a = getInt(param);
    String b = getString(param);
    boolean c = getBool(param);
    if (ModConfig.doSomethingElse) {
        doSomethingElse(a, b, c);
    } else if (ModConfig.doOriginal) {
        doSomething(a, b, c);
    } else {
        // No-op
    }
}

However, we can replace this Redirect with other injections for better comptability.

• If we want to replace the original call, we should use WrapOperation.
• If we just want to wrap the original call with a check, we should use WrapWithCondition.