difficult-to-diagnose errors using "difftime" response in a linear model

Fixes #678

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: performance
 Title: Assessment of Regression Models Performance
-Version: 0.10.8.11
+Version: 0.10.8.12
 Authors@R: 
     c(person(given = "Daniel",
              family = "Lüdecke",

NEWS.md

@@ -26,6 +26,9 @@
 * `check_outliers()` now properly accept the `percentage_central` argument when
   using the `"mcd"` method.
 
+* Fixed edge cases in `check_collinearity()` and `check_outliers()` for models
+  with response variables of classes `Date`, `POSIXct`, `POSIXlt` or `difftime`.
+
 # performance 0.10.8
 
 ## Changes

R/check_collinearity.R

@@ -404,7 +404,18 @@ check_collinearity.zerocount <- function(x,
 
 
 .check_collinearity <- function(x, component, ci = 0.95, verbose = TRUE) {
-  v <- insight::get_varcov(x, component = component, verbose = FALSE)
+  v <- .safe(insight::get_varcov(x, component = component, verbose = FALSE))
+
+  # sanity check
+  if (is.null(v)) {
+    if (isTRUE(verbose)) {
+      insight::format_alert(
+        sprintf("Could not extract the variance-covariance matrix for the %s component of the model.", component)
+      )
+    }
+    return(NULL)
+  }
+
   term_assign <- .term_assignments(x, component, verbose = verbose)
 
   # any assignment found?
@@ -432,10 +443,8 @@ check_collinearity.zerocount <- function(x,
   if (insight::has_intercept(x)) {
     v <- v[-1, -1]
     term_assign <- term_assign[-1]
-  } else {
-    if (isTRUE(verbose)) {
-      insight::format_alert("Model has no intercept. VIFs may not be sensible.")
-    }
+  } else if (isTRUE(verbose)) {
+    insight::format_alert("Model has no intercept. VIFs may not be sensible.")
   }
 
   f <- insight::find_formula(x)

R/check_outliers.R

@@ -23,6 +23,7 @@
 #'   'Details'). If a numeric value is given, it will be used as the threshold
 #'   for any of the method run.
 #' @param ID Optional, to report an ID column along with the row number.
+#' @param verbose Toggle warnings.
 #' @param ... When `method = "ics"`, further arguments in `...` are passed
 #' down to [ICSOutlier::ics.outlier()]. When `method = "mahalanobis"`,
 #' they are  passed down to [stats::mahalanobis()]. `percentage_central` can
@@ -348,6 +349,7 @@ check_outliers.default <- function(x,
                                    method = c("cook", "pareto"),
                                    threshold = NULL,
                                    ID = NULL,
+                                   verbose = TRUE,
                                    ...) {
   # Check args
   if (all(method == "all")) {
@@ -391,8 +393,18 @@ check_outliers.default <- function(x,
   # Get data
   my_data <- insight::get_data(x, verbose = FALSE)
 
+  # sanity check for date, POSIXt and difftime variables
+  if (any(vapply(my_data, inherits, FUN.VALUE = logical(1), what = c("Date", "POSIXt", "difftime"))) && verbose) {
+    insight::format_alert("Date variables are not supported for outliers detection. These will be ignored.")
+  }
+
   # Remove non-numerics
-  my_data <- datawizard::data_select(my_data, select = is.numeric)
+  my_data <- datawizard::data_select(my_data, select = is.numeric, verbose = FALSE)
+
+  # check if any data left
+  if (is.null(my_data) || ncol(my_data) == 0) {
+    insight::format_error("No numeric variables found. No data to check for outliers.")
+  }
 
   # Thresholds
   if (is.null(threshold)) {
@@ -409,7 +421,7 @@ check_outliers.default <- function(x,
     )
   }
 
-  if (!missing(ID)) {
+  if (!missing(ID) && verbose) {
     insight::format_warning(paste0("ID argument not supported for model objects of class `", class(x)[1], "`."))
   }
 

tests/testthat/test-check_collinearity.R

@@ -211,3 +211,9 @@ test_that("check_collinearity, hurdle/zi models w/o zi-formula", {
   )
   expect_equal(out$VIF, c(1.05772, 1.05772, 1.06587, 1.06587), tolerance = 1e-4)
 })
+
+test_that("check_collinearity, invalid data", {
+  dd <- data.frame(y = as.difftime(0:5, units = "days"))
+  m1 <- lm(y ~ 1, data = dd)
+  expect_message(expect_null(check_collinearity(m1)), "Could not extract")
+})

tests/testthat/test-check_outliers.R

@@ -329,3 +329,16 @@ test_that("cook multiple methods which", {
     c("setosa", "versicolor", "virginica")
   )
 })
+
+
+test_that("check_outliers with invald data", {
+  dd <- data.frame(y = as.difftime(0:5, units = "days"))
+  m1 <- lm(y ~ 1, data = dd)
+  expect_error(
+    expect_message(
+      check_outliers(m1),
+      regex = "Date variables are not supported"
+    ),
+    regex = "No numeric variables found"
+  )
+})