From 3985394a0fa0c06e0a78d202e9b2da658eb0d640 Mon Sep 17 00:00:00 2001
From: Daniel <mail@danielluedecke.de>
Date: Fri, 16 Feb 2024 21:00:19 +0100
Subject: [PATCH] Errors in using r2_kullback Fixes #667

---
 DESCRIPTION        |  2 +-
 NAMESPACE          |  2 ++
 NEWS.md            |  2 ++
 R/r2_kl.R          | 14 +++++++++++++-
 man/r2_kullback.Rd |  7 ++++++-
 5 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index cdd668003..70adc6648 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Type: Package
 Package: performance
 Title: Assessment of Regression Models Performance
-Version: 0.10.8.15
+Version: 0.10.8.16
 Authors@R: 
     c(person(given = "Daniel",
              family = "Lüdecke",
diff --git a/NAMESPACE b/NAMESPACE
index 710374ed7..b483c40ad 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -429,6 +429,8 @@ S3method(r2_coxsnell,survreg)
 S3method(r2_coxsnell,svycoxph)
 S3method(r2_coxsnell,truncreg)
 S3method(r2_efron,default)
+S3method(r2_kullback,default)
+S3method(r2_kullback,glm)
 S3method(r2_loo_posterior,BFBayesFactor)
 S3method(r2_loo_posterior,brmsfit)
 S3method(r2_loo_posterior,stanmvreg)
diff --git a/NEWS.md b/NEWS.md
index 8327f127b..68d6fe215 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -28,6 +28,8 @@
   `check_collinearity()` and `check_outliers()` for models with non-numeric
   response variables.
 
+* `r2_kullback()` now gives an informative error for non-supported models.
+
 ## Bug fixes
 
 * Fixed issue in `binned_residuals()` for models with binary outcome, where
diff --git a/R/r2_kl.R b/R/r2_kl.R
index b5c1bb649..553e338e4 100644
--- a/R/r2_kl.R
+++ b/R/r2_kl.R
@@ -7,6 +7,7 @@
 #' @param model A generalized linear model.
 #' @param adjust Logical, if `TRUE` (the default), the adjusted R2 value is
 #'   returned.
+#' @param ... Additional arguments. Currently not used.
 #'
 #' @return A named vector with the R2 value.
 #'
@@ -19,7 +20,13 @@
 #' 77: 329-342.
 #'
 #' @export
-r2_kullback <- function(model, adjust = TRUE) {
+r2_kullback <- function(model, ...) {
+  UseMethod("r2_kullback")
+}
+
+#' @rdname r2_kullback
+#' @export
+r2_kullback.glm <- function(model, adjust = TRUE, ...) {
   if (adjust) {
     adj <- model$df.null / model$df.residual
   } else {
@@ -31,3 +38,8 @@ r2_kullback <- function(model, adjust = TRUE) {
   names(klr2) <- "Kullback-Leibler R2"
   klr2
 }
+
+#' @export
+r2_kullback.default <- function(model, ...) {
+  insight::format_error("This function only works for objects of class `glm`.")
+}
diff --git a/man/r2_kullback.Rd b/man/r2_kullback.Rd
index d2980d18e..ae0f9dd55 100644
--- a/man/r2_kullback.Rd
+++ b/man/r2_kullback.Rd
@@ -2,13 +2,18 @@
 % Please edit documentation in R/r2_kl.R
 \name{r2_kullback}
 \alias{r2_kullback}
+\alias{r2_kullback.glm}
 \title{Kullback-Leibler R2}
 \usage{
-r2_kullback(model, adjust = TRUE)
+r2_kullback(model, ...)
+
+\method{r2_kullback}{glm}(model, adjust = TRUE, ...)
 }
 \arguments{
 \item{model}{A generalized linear model.}
 
+\item{...}{Additional arguments. Currently not used.}
+
 \item{adjust}{Logical, if \code{TRUE} (the default), the adjusted R2 value is
 returned.}
 }