Assume stringsAsFactors=FALSE

.lintr

@@ -28,6 +28,8 @@ linters: all_linters(
     absolute_path_linter = NULL,
     library_call_linter = NULL,
     nonportable_path_linter = NULL,
+    # We now require R>=4.0.0
+    strings_as_factors_linter = NULL,
     todo_comment_linter = NULL,
     # TODO(#2327): Enable this.
     unreachable_code_linter = NULL

R/get_source_expressions.R

@@ -636,8 +636,7 @@ fix_eq_assigns <- function(pc) {
     parent = integer(n_expr),
     token = character(n_expr),
     terminal = logical(n_expr),
-    text = character(n_expr),
-    stringsAsFactors = FALSE
+    text = character(n_expr)
   )
 
   for (i in seq_len(n_expr)) {

R/linter_tags.R

@@ -82,11 +82,7 @@ available_linters <- function(packages = "lintr", tags = NULL, exclude_tags = "d
 }
 
 build_available_linters <- function(available, package, tags, exclude_tags) {
-  available_df <- data.frame(
-    linter = available[["linter"]],
-    package,
-    stringsAsFactors = FALSE
-  )
+  available_df <- data.frame(linter = available[["linter"]], package)
   available_df$tags <- strsplit(available[["tags"]], split = " ", fixed = TRUE)
   if (!is.null(tags)) {
     matches_tags <- vapply(available_df$tags, function(linter_tags) any(linter_tags %in% tags), logical(1L))
@@ -108,7 +104,7 @@ build_available_linters <- function(available, package, tags, exclude_tags) {
 #' `data.frame` constructors don't handle zero-row list-columns properly, so supply `tags` afterwards.
 #' @noRd
 empty_linters <- function() {
-  empty_df <- data.frame(linter = character(), package = character(), stringsAsFactors = FALSE)
+  empty_df <- data.frame(linter = character(), package = character())
   empty_df$tags <- list()
   empty_df
 }

R/methods.R

@@ -163,8 +163,7 @@ as.data.frame.lints <- function(x, row.names = NULL, optional = FALSE, ...) { #
     type = vapply(x, `[[`, character(1L), "type"),
     message = vapply(x, `[[`, character(1L), "message"),
     line = vapply(x, `[[`, character(1L), "line"),
-    linter = vapply(x, `[[`, character(1L), "linter"),
-    stringsAsFactors = FALSE
+    linter = vapply(x, `[[`, character(1L), "linter")
   )
 }
 
@@ -198,7 +197,7 @@ summary.lints <- function(object, ...) {
   )
   tbl <- table(filenames, types)
   filenames <- rownames(tbl)
-  res <- as.data.frame.matrix(tbl, stringsAsFactors = FALSE, row.names = NULL)
+  res <- as.data.frame.matrix(tbl, row.names = NULL)
   res$filenames <- filenames %||% character()
   nms <- colnames(res)
   res[order(res$filenames), c("filenames", nms[nms != "filenames"])]

R/namespace.R

@@ -24,18 +24,18 @@ safe_get_exports <- function(ns) {
 
   # importFrom directives appear as list(ns, imported_funs)
   if (length(ns) > 1L) {
-    return(data.frame(pkg = ns[[1L]], fun = ns[[2L]], stringsAsFactors = FALSE))
+    return(data.frame(pkg = ns[[1L]], fun = ns[[2L]]))
   }
 
   # relevant only if there are any exported objects
   fun <- getNamespaceExports(ns)
   if (length(fun) > 0L) {
-    data.frame(pkg = ns, fun = fun, stringsAsFactors = FALSE)
+    data.frame(pkg = ns, fun = fun)
   }
 }
 
 empty_namespace_data <- function() {
-  data.frame(pkg = character(), fun = character(), stringsAsFactors = FALSE)
+  data.frame(pkg = character(), fun = character())
 }
 
 # filter namespace_imports() for S3 generics
@@ -64,11 +64,7 @@ exported_s3_generics <- function(path = find_package(".")) {
     return(empty_namespace_data())
   }
 
-  data.frame(
-    pkg = basename(path),
-    fun = unique(namespace_data$S3methods[, 1L]),
-    stringsAsFactors = FALSE
-  )
+  data.frame(pkg = basename(path), fun = unique(namespace_data$S3methods[, 1L]))
 }
 
 is_s3_generic <- function(fun) {

R/object_overwrite_linter.R

@@ -66,8 +66,7 @@ object_overwrite_linter <- function(
   )
   pkg_exports <- data.frame(
     package = rep(packages, lengths(pkg_exports)),
-    name = unlist(pkg_exports),
-    stringsAsFactors = FALSE
+    name = unlist(pkg_exports)
   )
 
   # Take the first among duplicate names, e.g. 'plot' resolves to base::plot, not graphics::plot

R/shared_constants.R

@@ -115,7 +115,7 @@ get_token_replacement <- function(token_content, token_type) {
 #   r_string gives the operator as you would write it in R code.
 
 # styler: off
-infix_metadata <- data.frame(stringsAsFactors = FALSE, matrix(byrow = TRUE, ncol = 2L, c(
+infix_metadata <- data.frame(matrix(byrow = TRUE, ncol = 2L, c(
   "OP-PLUS",         "+",
   "OP-MINUS",        "-",
   "OP-TILDE",        "~",

tests/testthat/test-fixed_regex_linter.R

@@ -68,7 +68,7 @@ patrick::with_parameters_test_that(
       "|", "[", "]", "\\\\", "<", ">", "=", ":", ";", "/",
       "_", "-", "!", "@", "#", "%", "&", "~"
     )
-    data.frame(char = char, .test_name = char, stringsAsFactors = FALSE)
+    data.frame(char = char, .test_name = char)
   })
 )
 

tests/testthat/test-linter_tags.R

@@ -13,11 +13,7 @@ test_that("validate_linter_db works as expected", {
   )
   expect_false(suppressWarnings(lintr:::validate_linter_db(df_empty, "mypkg")))
 
-  df <- data.frame(
-    linter = "absolute_path_linter",
-    tags = "robustness",
-    stringsAsFactors = FALSE
-  )
+  df <- data.frame(linter = "absolute_path_linter", tags = "robustness")
   expect_true(lintr:::validate_linter_db(df, "mypkg"))
 })
 
@@ -160,6 +156,7 @@ test_that("lintr help files are up to date", {
   )
 
   # Counts of tags from available_linters()
+  #   NB: as.data.frame.table returns stringsAsFactors=TRUE default in R>4
   db_tag_table <- as.data.frame(
     table(tag = unlist(lintr_db$tags)),
     responseName = "n_linters",

tests/testthat/test-methods.R

@@ -56,14 +56,13 @@ test_that("as.data.frame.lints", {
   expect_s3_class(df, "data.frame")
 
   exp <- data.frame(
-    filename = rep("dummy.R", 2L),
+    filename = "dummy.R",
     line_number = c(1L, 2L),
     column_number = c(1L, 6L),
     type = c("style", "error"),
     message = c("", "Under no circumstances is the use of foobar allowed."),
     line = c("", "a <- 1"),
-    linter = c(NA_character_, NA_character_), # These are assigned in lint() now.
-    stringsAsFactors = FALSE
+    linter = NA_character_ # These are assigned in lint() now.
   )
 
   expect_identical(df, exp)

tests/testthat/test-with.R

@@ -24,12 +24,7 @@ test_that("linters_with_defaults warns on unused NULLs", {
 test_that("linters_with_tags() verifies the output of available_linters()", {
   local_mocked_bindings(
     available_linters = function(...) {
-      data.frame(
-        linter = c("fake_linter", "very_fake_linter"),
-        package = "lintr",
-        tags = "",
-        stringsAsFactors = FALSE
-      )
+      data.frame(linter = c("fake_linter", "very_fake_linter"), package = "lintr", tags = "")
     }
   )
   expect_error(

vignettes/lintr.Rmd

@@ -140,10 +140,7 @@ make_string <- function(x) {
   }
 }
 
-defaults_table <- data.frame(
-  default = vapply(default_settings, make_string, character(1L)),
-  stringsAsFactors = FALSE
-)
+defaults_table <- data.frame(default = vapply(default_settings, make_string, character(1L)))
 
 # avoid conflict when loading lintr in echo=TRUE cell below
 rm(default_settings)
@@ -196,8 +193,7 @@ make_setting_string <- function(linter_name) {
 
 defaults_table <- data.frame(
   row.names = names(default_linters),
-  settings = vapply(names(default_linters), make_setting_string, character(1L)),
-  stringsAsFactors = FALSE
+  settings = vapply(names(default_linters), make_setting_string, character(1L))
 )
 
 knitr::kable(defaults_table)