box function import count linter

R/linter_box_function_import_count_linter.R

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+#' Box library function import count linter
+#'
+#' Checks that function imports do not exceed the defined `max`. Defaults to 5.
+#'
+#' @param max Maximum function imports allowed between `[` and `]`. Defaults to 5.
+#'
+#' @examples
+#' # will produce lints
+#' lintr::lint(
+#'   text = "box::use(package[one, two, three, four, five, six, ])",
+#'   linters = box_func_import_count_linter()
+#' )
+#' 
+#' lintr::lint(
+#'   text = "box::use(package[one, two, three, four, ])",
+#'   linters = box_func_import_count_linter(3)
+#' )
+#' 
+#' # okay
+#' lintr::lint(
+#'   text = "box::use(package[one, two, three, four, five, ])",
+#'   linters = box_func_import_count_linter()
+#' )
+#' 
+#' lintr::lint(
+#'   text = "box::use(package[one, two, three, ])",
+#'   linters = box_func_import_count_linter(3)
+#' )
+#' 
+#' @export
+box_func_import_count_linter <- function(max = 5L) {
+  xpath <- glue::glue("//SYMBOL_PACKAGE[
+                      (text() = 'box' and
+                      following-sibling::SYMBOL_FUNCTION_CALL[text() = 'use'])
+                    ]
+/parent::expr
+/parent::expr
+/descendant::OP-LEFT-BRACKET[
+  count(
+    following-sibling::expr[
+      count(. | ..//OP-RIGHT-BRACKET/preceding-sibling::expr) =
+        count(../OP-RIGHT-BRACKET/preceding-sibling::expr)
+    ]
+  ) > {max}
+]
+/parent::expr")
+
+  lint_message <- glue::glue("Limit the function imports to a max of {max}.")
+
+  lintr::Linter(function(source_expression) {
+    if (!lintr::is_lint_level(source_expression, "file")) {
+      return(list())
+    }
+
+    xml <- source_expression$full_xml_parsed_content
+
+    bad_expr <- xml2::xml_find_all(xml, xpath)
+
+    lintr::xml_nodes_to_lints(
+      bad_expr,
+      source_expression = source_expression,
+      lint_message = lint_message,
+      type = "style"
+    )
+  })
+}

tests/testthat/test-linter_box_function_import_count_linter.R

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+five_function_imports <- "box::use(
+  dplyr[
+    arrange,
+    select,
+    mutate,
+    distinct,
+    filter,
+  ],
+)"
+
+five_function_imports_inline <- "box::use(
+  dplyr[arrange, select, mutate, distinct, filter, ],
+)"
+
+six_function_imports <- "box::use(
+  dplyr[
+    arrange,
+    select,
+    mutate,
+    distinct,
+    filter,
+    slice,
+  ],
+)"
+
+six_function_imports_inline <- "box::use(
+  dplyr[arrange, select, mutate, distinct, filter, slice, ],
+)"
+
+three_function_imports <- "box::use(
+  dplyr[
+    arrange,
+    select,
+    mutate,
+  ],
+)"
+
+three_function_imports_inline <- "box::use(
+  dplyr[arrange, select, mutate, ],
+)"
+
+lint_message <- function(max = 5L) {
+  rex::rex(glue::glue("Limit the function imports to a max of {max}."))
+}
+
+test_that("box_func_import_count_linter skips allowed function count.", {
+  linter <- box_func_import_count_linter()
+
+  lintr::expect_lint(five_function_imports, NULL, )
+  lintr::expect_lint(five_function_imports_inline, NULL, linter)
+})
+
+test_that("box_func_import_count_linter skips allowed function count supplied max", {
+  linter <- box_func_import_count_linter(max = 3)
+
+  lintr::expect_lint(three_function_imports, NULL, )
+  lintr::expect_lint(three_function_imports_inline, NULL, linter)
+})
+
+test_that("box_func_import_count_linter blocks function imports more than max", {
+  max <- 5
+  linter <- box_func_import_count_linter(max = max)
+  lint_msg <- lint_message(max)
+
+  lintr::expect_lint(six_function_imports, list(message = lint_msg), linter)
+  lintr::expect_lint(six_function_imports_inline, list(message = lint_msg), linter)
+})