Automatically add .lintr to .Rbuildignore by the use_lintr function

DESCRIPTION

@@ -47,7 +47,8 @@ Suggests:
     testthat (>= 3.0.0),
     tibble,
     tufte,
-    withr (>= 2.5.0)
+    withr (>= 2.5.0),
+    xfun
 VignetteBuilder: 
     knitr
 Config/Needs/website: tidyverse/tidytemplate

R/use_lintr.R

@@ -43,5 +43,29 @@ use_lintr <- function(path = ".", type = c("tidyverse", "full")) {
     )
   )
   write.dcf(the_config, config_file, width = Inf)
+
+  # If this is an R package and if available, add .lintr file to .Rbuildignore
+  if (file.exists("DESCRIPTION") && file.exists(".Rbuildignore")) {
+    try(
+      add_build_ignore(config_file),
+      silent = TRUE
+    )
+  }
+
   invisible(config_file)
 }
+
+add_build_ignore <- function(path) {
+  path_build_ignore <- file.path(".", ".Rbuildignore")
+  existing_lines <- xfun::read_utf8(path_build_ignore)
+
+  escape_path <- rex::rex(start, rex::re_substitutes(path, list(start, "./") %or% list("/", end), ""), end)
+
+  new_lines <- c(existing_lines, setdiff(escape_path, existing_lines))
+
+  xfun::write_utf8(new_lines, path_build_ignore)
+
+  message("Add '", escape_path, "' to ", path_build_ignore)
+
+  invisible(NULL)
+}

tests/testthat/_snaps/use_lintr.md

@@ -0,0 +1,9 @@
+# use_lintr add .lintr to .Rbuildignore for packages
+
+    Code
+      cat(brio::read_file(file.path(tmp_package_dir, ".Rbuildignore")))
+    Output
+      ^lintr\.Rproj$
+      ^\.Rproj\.user$
+      ^\.lintr$
+

tests/testthat/test-use_lintr.R

@@ -35,3 +35,15 @@ test_that("use_lintr with type = full also works", {
   lints <- lint_dir(tmp)
   expect_length(lints, 0L)
 })
+
+test_that("use_lintr add .lintr to .Rbuildignore for packages", {
+  tmp <- withr::local_tempdir()
+  tmp_package_dir <- paste0(tmp, "/package")
+  package_dir <- test_path("dummy_packages", "package")
+  dir.create(tmp_package_dir)
+  file.copy(package_dir, tmp, recursive = TRUE)
+  setwd(tmp_package_dir)
+  lintr_file <- use_lintr()
+  expect_true(file.exists(lintr_file))
+  expect_snapshot(cat(brio::read_file(file.path(tmp_package_dir, ".Rbuildignore"))))
+})