add dry argument: either write back, fail on change or don't fail on change

Author: lorenzwalthert

API

@@ -10,9 +10,9 @@ create_style_guide(initialize = default_style_guide_attributes, line_break = NUL
 default_style_guide_attributes(pd_flat)
 specify_math_token_spacing(zero = "'^'", one = c("'+'", "'-'", "'*'", "'/'"))
 specify_reindention(regex_pattern = NULL, indention = 0, comments_only = TRUE)
-style_dir(path = ".", ..., style = tidyverse_style, transformers = style(...), filetype = c("R", "Rprofile"), recursive = TRUE, exclude_files = NULL, exclude_dirs = c("packrat", "renv"), include_roxygen_examples = TRUE)
-style_file(path, ..., style = tidyverse_style, transformers = style(...), include_roxygen_examples = TRUE)
-style_pkg(pkg = ".", ..., style = tidyverse_style, transformers = style(...), filetype = c("R", "Rprofile"), exclude_files = "R/RcppExports.R", exclude_dirs = c("packrat", "renv"), include_roxygen_examples = TRUE)
+style_dir(path = ".", ..., style = tidyverse_style, transformers = style(...), filetype = c("R", "Rprofile"), recursive = TRUE, exclude_files = NULL, exclude_dirs = c("packrat", "renv"), include_roxygen_examples = TRUE, dry = "off")
+style_file(path, ..., style = tidyverse_style, transformers = style(...), include_roxygen_examples = TRUE, dry = "off")
+style_pkg(pkg = ".", ..., style = tidyverse_style, transformers = style(...), filetype = c("R", "Rprofile"), exclude_files = "R/RcppExports.R", exclude_dirs = c("packrat", "renv"), include_roxygen_examples = TRUE, dry = "off")
 style_text(text, ..., style = tidyverse_style, transformers = style(...), include_roxygen_examples = TRUE)
 tidyverse_math_token_spacing()
 tidyverse_reindention()

R/io.R

@@ -1,34 +1,56 @@
 #' Apply a function to the contents of a file
 #'
 #' Transforms a file with a function.
-#' @param path A vector with file paths to transform.
-#' @param fun A function that returns a character vector.
-#' @param write_back Whether or not the results of the transformation should
-#'   be written back to the file.
 #' @importFrom magrittr set_names
 #' @importFrom rlang abort
+#' @inheritParams transform_utf8_one
 #' @keywords internal
-transform_utf8 <- function(path, fun, write_back = TRUE) {
-  map_lgl(path, transform_utf8_one, fun = fun, write_back = write_back) %>%
+transform_utf8 <- function(path, fun, dry) {
+  map_lgl(path, transform_utf8_one, fun = fun, dry = dry) %>%
     set_names(path)
 }
 
+#' Potentially transform a file
+#'
+#' @param path A vector with file paths to transform.
+#' @param fun A function that returns a character vector.
+#' @param dry To indicate whether styler should run in *dry* mode, i.e. refrain
+#'   from write back to files .`"on"` and `"fail"` both don't write back, the
+#'   latter returns an error if styling *would* change contents. "off", the
+#'   default, writes back if the input and output of styling are not identical.
 #' @importFrom rlang with_handlers warn
-transform_utf8_one <- function(path, fun, write_back) {
+#' @keywords internal
+transform_utf8_one <- function(path, fun, dry) {
+  rlang::arg_match(dry, c("on", "off", "fail"))
   with_handlers(
     {
       file_with_info <- read_utf8(path)
       # only write back when changed OR when there was a missing newline
       new <- fun(file_with_info$text)
       identical_content <- identical(unclass(file_with_info$text), unclass(new))
       identical <- identical_content && !file_with_info$missing_EOF_line_break
-      if (!identical && write_back) {
-        xfun::write_utf8(new, path)
+      if (!identical) {
+        if (dry == "fail") {
+          rlang::abort(
+            paste0("File `", path, "` would be modified by styler and `dry` = 'fail'."),
+            class = "dryError"
+          )
+        } else if (dry == "on") {
+          # don't do anything
+        } else if (dry == "off") {
+          xfun::write_utf8(new, path)
+        } else {
+          # not implemented
+        }
       }
       !identical
     },
     error = function(e) {
-      warn(paste0("When processing ", path, ": ", conditionMessage(e)))
+      if (inherits(e, "dryError")) {
+        rlang::abort(conditionMessage(e))
+      } else {
+        warn(paste0("When processing ", path, ": ", conditionMessage(e)))
+      }
       NA
     }
   )

R/testing.R

@@ -20,7 +20,7 @@
 #' @importFrom rlang abort
 #' @keywords internal
 test_collection <- function(test, sub_test = NULL,
-                            write_back = TRUE,
+                            dry = "off",
                             write_tree = NA,
                             transformer,
                             ...) {
@@ -49,7 +49,7 @@ test_collection <- function(test, sub_test = NULL,
   pwalk(list(in_items, out_items, in_names, out_names, out_trees),
     transform_and_check,
     transformer = transformer,
-    write_back = write_back,
+    dry = dry,
     write_tree = write_tree,
     ...
   )
@@ -87,20 +87,19 @@ construct_tree <- function(in_paths, suffix = "_tree") {
 #' @param in_name The label of the in_item, defaults to `in_item`.
 #' @param out_name The label of the out_item, defaults to `out_item`.
 #' @param transformer A function to apply to the content of `in_item`.
-#' @param write_back Whether the results of the transformation should be written
-#'   to the output file.
 #' @param write_tree Whether or not the tree structure of the test should be
 #'   computed and written to a file. Note that this needs R >= 3.2
 #'   (see [set_arg_write_tree()]). If the argument is set to `NA`, the function
 #'   determines whether R >= 3.2 is in use and if so, trees will be written.
 #' @param ... Parameters passed to transformer function.
 #' @param out_tree Name of tree file if written out.
+#' @inheritParams transform_utf8
 #' @importFrom utils write.table
 #' @importFrom rlang warn
 #' @keywords internal
 transform_and_check <- function(in_item, out_item,
                                 in_name = in_item, out_name = out_item,
-                                transformer, write_back,
+                                transformer, dry,
                                 write_tree = NA,
                                 out_tree = "_tree", ...) {
   write_tree <- set_arg_write_tree(write_tree)
@@ -121,7 +120,7 @@ transform_and_check <- function(in_item, out_item,
   transformed <- transform_utf8(
     out_item,
     function(x) transformed_text,
-    write_back = write_back
+    dry = dry
   )
 
   if (transformed) {
@@ -234,17 +233,19 @@ copy_to_tempdir <- function(path_perm = testthat_file()) {
 #'   first run.
 #' @keywords internal
 n_times_faster_with_cache <- function(x1, x2 = x1, ...,
-                                fun = styler::style_text,
-                                n = 3,
-                                clear = "always") {
+                                      fun = styler::style_text,
+                                      n = 3,
+                                      clear = "always") {
   rlang::arg_match(clear, c("always", "final", "never", "all but last"))
   capture.output(
     out <- purrr::map(1:n, n_times_faster_bench,
       x1 = x1, x2 = x2, fun = fun,
-      ..., n = n, clear = clear) %>%
-    purrr::map_dbl(
-      ~ unname(.x$first["elapsed"] / .x$second["elapsed"])) %>%
-    mean()
+      ..., n = n, clear = clear
+    ) %>%
+      purrr::map_dbl(
+        ~ unname(.x$first["elapsed"] / .x$second["elapsed"])
+      ) %>%
+      mean()
   )
   if (clear %in% c("always", "final")) {
     clear_testthat_cache()
@@ -267,7 +268,7 @@ n_times_faster_bench <- function(i, x1, x2, fun, ..., n, clear) {
   }
   list(
     first = first,
-    second =  second
+    second = second
   )
 }
 
@@ -320,4 +321,3 @@ fresh_testthat_cache <- function() {
   clear_testthat_cache()
   activate_testthat_cache()
 }
-

R/transform-code.R

@@ -8,18 +8,18 @@
 #' @param ... Further arguments passed to [transform_utf8()].
 #' @importFrom rlang abort
 #' @keywords internal
-transform_code <- function(path, fun, ...) {
+transform_code <- function(path, fun, ..., dry) {
   if (is_plain_r_file(path) || is_rprofile_file(path)) {
-    transform_utf8(path, fun = fun, ...)
+    transform_utf8(path, fun = fun, ..., dry = dry)
   } else if (is_rmd_file(path)) {
     transform_utf8(path,
       fun = partial(transform_mixed, transformer_fun = fun, filetype = "Rmd"),
-      ...
+      ..., dry = dry
     )
   } else if (is_rnw_file(path)) {
     transform_utf8(path,
       fun = partial(transform_mixed, transformer_fun = fun, filetype = "Rnw"),
-      ...
+      ..., dry = dry
     )
   } else {
     abort(paste(path, "is not an R, Rmd or Rnw file"))

R/transform-files.R

@@ -5,11 +5,13 @@
 #' @param files A character vector with paths to the file that should be
 #'   transformed.
 #' @inheritParams make_transformer
+#' @inheritParams transform_file
 #' @section Value:
 #' Invisibly returns a data frame that indicates for each file considered for
-#' styling whether or not it was actually changed.
+#' styling whether or not it was actually changed (or would be changed when
+#' `dry` is not "off").
 #' @keywords internal
-transform_files <- function(files, transformers, include_roxygen_examples) {
+transform_files <- function(files, transformers, include_roxygen_examples, dry) {
   transformer <- make_transformer(transformers, include_roxygen_examples)
   max_char <- min(max(nchar(files), 0), getOption("width"))
   len_files <- length(files)
@@ -18,7 +20,7 @@ transform_files <- function(files, transformers, include_roxygen_examples) {
   }
 
   changed <- map_lgl(files, transform_file,
-    fun = transformer, max_char_path = max_char
+    fun = transformer, max_char_path = max_char, dry = dry
   )
   communicate_summary(changed, max_char)
   communicate_warning(changed, transformers)
@@ -34,7 +36,7 @@ transform_files <- function(files, transformers, include_roxygen_examples) {
 #' @param message_after The message to print after the path.
 #' @param message_after_if_changed The message to print after `message_after` if
 #'   any file was transformed.
-#' @inheritParams transform_utf8
+#' @inheritParams transform_code
 #' @param ... Further arguments passed to [transform_utf8()].
 #' @keywords internal
 transform_file <- function(path,
@@ -43,7 +45,8 @@ transform_file <- function(path,
                            message_before = "",
                            message_after = " [DONE]",
                            message_after_if_changed = " *",
-                           ...) {
+                           ...,
+                           dry) {
   char_after_path <- nchar(message_before) + nchar(path) + 1
   max_char_after_message_path <- nchar(message_before) + max_char_path + 1
   n_spaces_before_message_after <-
@@ -53,7 +56,7 @@ transform_file <- function(path,
     rep_char(" ", max(0L, n_spaces_before_message_after)),
     append = FALSE
   )
-  changed <- transform_code(path, fun = fun, ...)
+  changed <- transform_code(path, fun = fun, ..., dry = dry)
 
   bullet <- ifelse(is.na(changed), "warning", ifelse(changed, "info", "tick"))
 

R/ui-styling.R

@@ -19,17 +19,7 @@ NULL
 #' @param transformers A set of transformer functions. This argument is most
 #'   conveniently constructed via the `style` argument and `...`. See
 #'   'Examples'.
-#' @param filetype Vector of file extensions indicating which file types should
-#'   be styled. Case is ignored, and the `.` is optional, e.g.
-#'   `c(".R", ".Rmd")`, or `c("r", "rmd")`. Supported values (after
-#'   standardization) are: "r", "rprofile", "rmd", "rnw".
-#' @param exclude_files Character vector with paths to files that should be
-#'   excluded from styling.
-#' @param exclude_dirs Character vector with directories to exclude. Note that
-#'   the default values were set for consistency with [style_dir()] and as
-#'   these directories are anyways not styled.
-#' @param include_roxygen_examples Whether or not to style code in roxygen
-#'   examples.
+#' @inheritParams prettify_pkg
 #' @section Warning:
 #' This function overwrites files (if styling results in a change of the
 #' code to be formatted). It is strongly suggested to only style files
@@ -78,20 +68,35 @@ style_pkg <- function(pkg = ".",
                       filetype = c("R", "Rprofile"),
                       exclude_files = "R/RcppExports.R",
                       exclude_dirs = c("packrat", "renv"),
-                      include_roxygen_examples = TRUE) {
+                      include_roxygen_examples = TRUE,
+                      dry = "off") {
   pkg_root <- rprojroot::find_package_root_file(path = pkg)
   changed <- withr::with_dir(pkg_root, prettify_pkg(
     transformers,
-    filetype, exclude_files, exclude_dirs, include_roxygen_examples
+    filetype, exclude_files, exclude_dirs, include_roxygen_examples, dry
   ))
   invisible(changed)
 }
 
+#' Prettify a package
+#'
+#' @param filetype Vector of file extensions indicating which file types should
+#'   be styled. Case is ignored, and the `.` is optional, e.g.
+#'   `c(".R", ".Rmd")`, or `c("r", "rmd")`. Supported values (after
+#'   standardization) are: "r", "rprofile", "rmd", "rnw".
+#' @param exclude_files Character vector with paths to files that should be
+#'   excluded from styling.
+#' @param exclude_dirs Character vector with directories to exclude. Note that
+#'   the default values were set for consistency with [style_dir()] and as
+#'   these directories are anyways not styled.
+#' @inheritParams transform_files
+#' @keywords internal
 prettify_pkg <- function(transformers,
                          filetype,
                          exclude_files,
                          exclude_dirs,
-                         include_roxygen_examples) {
+                         include_roxygen_examples,
+                         dry) {
   filetype <- set_and_assert_arg_filetype(filetype)
   r_files <- rprofile_files <- vignette_files <- readme <- NULL
   exclude_files <- set_arg_paths(exclude_files)
@@ -137,7 +142,7 @@ prettify_pkg <- function(transformers,
     c(r_files, rprofile_files, vignette_files, readme),
     exclude_files
   )
-  transform_files(files, transformers, include_roxygen_examples)
+  transform_files(files, transformers, include_roxygen_examples, dry)
 }
 
 #' Style a string
@@ -194,11 +199,13 @@ style_dir <- function(path = ".",
                       recursive = TRUE,
                       exclude_files = NULL,
                       exclude_dirs = c("packrat", "renv"),
-                      include_roxygen_examples = TRUE) {
+                      include_roxygen_examples = TRUE,
+                      dry = "off") {
   changed <- withr::with_dir(
     path, prettify_any(
       transformers,
-      filetype, recursive, exclude_files, exclude_dirs, include_roxygen_examples
+      filetype, recursive, exclude_files, exclude_dirs,
+      include_roxygen_examples, dry
     )
   )
   invisible(changed)
@@ -216,7 +223,8 @@ prettify_any <- function(transformers,
                          recursive,
                          exclude_files,
                          exclude_dirs,
-                         include_roxygen_examples) {
+                         include_roxygen_examples,
+                         dry) {
   exclude_files <- set_arg_paths(exclude_files)
   exclude_dirs <- set_arg_paths(exclude_dirs)
   files_root <- dir(
@@ -236,7 +244,7 @@ prettify_any <- function(transformers,
   }
   transform_files(
     setdiff(c(files_root, files_other), exclude_files),
-    transformers, include_roxygen_examples
+    transformers, include_roxygen_examples, dry
   )
 }
 
@@ -266,8 +274,9 @@ style_file <- function(path,
                        ...,
                        style = tidyverse_style,
                        transformers = style(...),
-                       include_roxygen_examples = TRUE) {
+                       include_roxygen_examples = TRUE,
+                       dry = "off") {
   path <- set_arg_paths(path)
-  changed <- transform_files(path, transformers, include_roxygen_examples)
+  changed <- transform_files(path, transformers, include_roxygen_examples, dry)
   invisible(changed)
 }