From d771f2c7beda24cb9c9707e0f64493d6e48ddd10 Mon Sep 17 00:00:00 2001
From: Daniel <mail@danielluedecke.de>
Date: Wed, 20 Nov 2024 12:30:25 +0100
Subject: [PATCH] find_transformation() returning multiple values Fixes #971

---
 DESCRIPTION                               |  2 +-
 NEWS.md                                   |  3 +++
 R/find_transformation.R                   | 18 +++++++++++-------
 tests/testthat/test-find_transformation.R | 16 ++++++++++++++++
 4 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index c96200b09..101c6a53c 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Type: Package
 Package: insight
 Title: Easy Access to Model Information for Various Model Objects
-Version: 0.99.0.15
+Version: 0.99.0.16
 Authors@R:
     c(person(given = "Daniel",
              family = "Lüdecke",
diff --git a/NEWS.md b/NEWS.md
index 4a93c1eb6..27f5c7310 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -62,6 +62,9 @@
 
 * Fixed issue in `compact_character()` and `compact_list()` for date-variables.
 
+* Fixed edge case in `find_transformation()` for simple log-transformation of
+  the response variable.
+
 # insight 0.20.5
 
 ## General
diff --git a/R/find_transformation.R b/R/find_transformation.R
index f82cfb9eb..b3c0e26d4 100644
--- a/R/find_transformation.R
+++ b/R/find_transformation.R
@@ -102,15 +102,19 @@ find_transformation.character <- function(x, ...) {
     if (grepl("log\\(log\\((.*)\\)\\)", x)) {
       transform_fun <- "log-log"
     } else {
-      # 1. try: log(x + number)
-      plus_minus <- .safe(
-        eval(parse(text = gsub("log\\(([^,\\+)]*)(.*)\\)", "\\2", x)))
-      )
-      # 2. try: log(number + x)
-      if (is.null(plus_minus)) {
+      plus_minus <- NULL
+      # make sure we definitly have a "+" in the log-transformation
+      if (grepl("+", x, fixed = TRUE)) {
+        # 1. try: log(x + number)
         plus_minus <- .safe(
-          eval(parse(text = gsub("log\\(([^,\\+)]*)(.*)\\)", "\\1", x)))
+          eval(parse(text = gsub("log\\(([^,\\+)]*)(.*)\\)", "\\2", x)))
         )
+        # 2. try: log(number + x)
+        if (is.null(plus_minus)) {
+          plus_minus <- .safe(
+            eval(parse(text = gsub("log\\(([^,\\+)]*)(.*)\\)", "\\1", x)))
+          )
+        }
       }
       if (is.null(plus_minus) || is.function(plus_minus)) {
         transform_fun <- "log"
diff --git a/tests/testthat/test-find_transformation.R b/tests/testthat/test-find_transformation.R
index f069cbe6c..4ee97378d 100644
--- a/tests/testthat/test-find_transformation.R
+++ b/tests/testthat/test-find_transformation.R
@@ -132,3 +132,19 @@ test_that("find_transformation - detect powers", {
     )
   )
 })
+
+
+test_that("find_transformation - works with log-edge cases", {
+  set.seed(1)
+  n <- 30
+  x <- rlnorm(n = n, meanlog = 3, sdlog = 1)
+  y <- exp(2 + log(x) + rnorm(n, sd = 3))
+  d <- data.frame(x, y)
+  m <- lm(log(y) ~ log(x), data = d)
+
+  expect_identical(find_transformation(m), "log")
+  expect_identical(
+    find_transformation(m, include_all = TRUE),
+    list(response = c(y = "log"), conditional = c(x = "log"))
+  )
+})