Lint, tweak error messages, refactor class+snap tests, guide on .col_…

…names

R/utils.R

@@ -358,18 +358,41 @@ assert_sufficient_f_args <- function(.f, ..., .ref_time_value_label) {
 #' @importFrom rlang is_function new_function f_env is_environment missing_arg
 #'  f_rhs is_formula caller_arg caller_env
 #' @keywords internal
-as_slide_computation <- function(.f, ..., .f_arg = caller_arg(.f), .call = caller_env(), .ref_time_value_long_varnames, .ref_time_value_label) {
-  f_arg <- .f_arg # for cli interpolation, avoid dot prefix
+as_slide_computation <- function(.f, ...,
+                                 .f_arg = caller_arg(.f), .call = caller_env(),
+                                 .ref_time_value_long_varnames, .ref_time_value_label) {
+  if (".col_names" %in% rlang::call_args_names(rlang::call_match())) {
+    cli_abort(
+      c("{.code epi_slide} and {.code epix_slide} do not support `.col_names`;
+         consider:",
+        "*" = "using {.code epi_slide_mean}, {.code epi_slide_sum}, or
+               {.code epi_slide_opt}, if applicable",
+        "*" = "using {.code .f = ~ .x %>%
+               dplyr::reframe(across(your_col_names, list(your_func_name = your_func)))}"
+      ),
+      call = .call,
+      class = "epiprocess__as_slide_computation__given_.col_names"
+    )
+  }
+
+  f_arg <- .f_arg # for cli interpolation, avoid dot prefix; # nolint: object_usage_linter
   withCallingHandlers(
     {
       force(.f)
     },
     error = function(e) {
       cli_abort(
         c("Failed to convert {.code {f_arg}} to a slide computation.",
-          "*" = "If you were trying to use the formula interface, maybe you forgot a tilde at the beginning.",
-          "*" = "If you were trying to use the tidyeval interface, maybe you forgot to specify the name, e.g.: `my_output_col_name =`.",
-          "*" = "If you were trying to use advanced features of the tidyeval interface such as `!! name_variable :=`, you might have forgotten the required leading comma."
+          "*" = "If you were trying to use the formula interface,
+                 maybe you forgot a tilde at the beginning.",
+          "*" = "If you were trying to use the tidyeval interface,
+                 maybe you forgot to specify the name,
+                 e.g.: `my_output_col_name =`.  Note that `.col_names`
+                 is not supported.",
+          "*" = "If you were trying to use advanced features of the
+                 tidyeval interface such as `!! name_variable :=`,
+                 maybe you forgot the required leading comma.",
+          "*" = "Something else could have gone wrong; see below."
         ),
         parent = e,
         call = .call,

tests/testthat/_snaps/utils.md

@@ -1,14 +1,26 @@
 # as_slide_computation raises errors as expected
 
     Code
-      toy_edf %>% group_by(geo_value) %>% epi_slide(.window_size = 6, tibble(
+      toy_edf %>% group_by(geo_value) %>% epi_slide(.window_size = 7, mean,
+        .col_names = "value")
+    Condition
+      Error in `epi_slide()`:
+      ! `epi_slide` and `epix_slide` do not support `.col_names`; consider:
+      * using `epi_slide_mean`, `epi_slide_sum`, or `epi_slide_opt`, if applicable
+      * using `.f = ~ .x %>% dplyr::reframe(across(your_col_names, list(your_func_name = your_func)))`
+
+---
+
+    Code
+      toy_edf %>% group_by(geo_value) %>% epi_slide(.window_size = 7, tibble(
         slide_value = mean(.x$value)))
     Condition
-      Error in `as_slide_computation()`:
+      Error in `epi_slide()`:
       ! Failed to convert `tibble(slide_value = mean(.x$value))` to a slide computation.
       * If you were trying to use the formula interface, maybe you forgot a tilde at the beginning.
-      * If you were trying to use the tidyeval interface, maybe you forgot to specify the name, e.g.: `my_output_col_name =`.
-      * If you were trying to use advanced features of the tidyeval interface such as `!! name_variable :=`, you might have forgotten the required leading comma.
+      * If you were trying to use the tidyeval interface, maybe you forgot to specify the name, e.g.: `my_output_col_name =`.  Note that `.col_names` is not supported.
+      * If you were trying to use advanced features of the tidyeval interface such as `!! name_variable :=`, maybe you forgot the required leading comma.
+      * Something else could have gone wrong; see below.
       Caused by error:
       ! object '.x' not found
 
@@ -17,11 +29,12 @@
     Code
       toy_archive %>% epix_slide(tibble(slide_value = mean(.x$value)))
     Condition
-      Error in `as_slide_computation()`:
+      Error in `epix_slide()`:
       ! Failed to convert `.f` to a slide computation.
       * If you were trying to use the formula interface, maybe you forgot a tilde at the beginning.
-      * If you were trying to use the tidyeval interface, maybe you forgot to specify the name, e.g.: `my_output_col_name =`.
-      * If you were trying to use advanced features of the tidyeval interface such as `!! name_variable :=`, you might have forgotten the required leading comma.
+      * If you were trying to use the tidyeval interface, maybe you forgot to specify the name, e.g.: `my_output_col_name =`.  Note that `.col_names` is not supported.
+      * If you were trying to use advanced features of the tidyeval interface such as `!! name_variable :=`, maybe you forgot the required leading comma.
+      * Something else could have gone wrong; see below.
       Caused by error:
       ! object '.x' not found
 

tests/testthat/test-utils.R

@@ -231,34 +231,36 @@ test_that("as_slide_computation raises errors as expected", {
     class = "epiprocess__as_slide_computation__cant_convert_catchall"
   )
 
+  # helper to make initial snapshots less error-prone:
+  expect_error_snapshot <- function(x, class) {
+    x_quo <- rlang::enquo(x)
+    rlang::inject(expect_error(!!x_quo, class = class)) # quick sanity check on class
+    rlang::inject(expect_snapshot(!!x_quo, error = TRUE)) # don't need cnd_class = TRUE since checked above
+  }
+
   # If `.f` doesn't look like tidyeval and we fail to force it, then we hint to
   # the user some potential problems:
   toy_edf <- tibble(geo_value = 1, time_value = c(1, 2), value = 1:2) %>%
     as_epi_df(as_of = 1)
   toy_archive <- tibble(version = c(1, 2, 2), geo_value = 1, time_value = c(1, 1, 2), value = 1:3) %>%
     as_epi_archive()
-  expect_error(
+  expect_error_snapshot(
     toy_edf %>%
       group_by(geo_value) %>%
-      epi_slide(.window_size = 6, tibble(slide_value = mean(.x$value))),
-    class = "epiprocess__as_slide_computation__error_forcing_.f"
+      epi_slide(.window_size = 7, mean, .col_names = "value"),
+    class = "epiprocess__as_slide_computation__given_.col_names"
   )
-  expect_snapshot(
-    error = TRUE,
+  expect_error_snapshot(
     toy_edf %>%
       group_by(geo_value) %>%
-      epi_slide(.window_size = 6, tibble(slide_value = mean(.x$value)))
+      epi_slide(.window_size = 7, tibble(slide_value = mean(.x$value))),
+    class = "epiprocess__as_slide_computation__error_forcing_.f"
   )
-  expect_error(
+  expect_error_snapshot(
     toy_archive %>%
       epix_slide(tibble(slide_value = mean(.x$value))),
     class = "epiprocess__as_slide_computation__error_forcing_.f"
   )
-  expect_snapshot(
-    error = TRUE,
-    toy_archive %>%
-      epix_slide(tibble(slide_value = mean(.x$value)))
-  )
 })
 
 test_that("as_slide_computation works", {