Merge pull request #532 from lorenzwalthert/fix-write-back

- Only write back when contents changed (#532).

Author: lorenzwalthert

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: styler
 Type: Package
 Title: Non-Invasive Pretty Printing of R Code
-Version: 1.1.1.9000
+Version: 1.1.1.9002
 Authors@R: 
     c(person(given = "Kirill",
              family = "Müller",

NEWS.md

@@ -6,6 +6,9 @@
   directories. We no longer display the file name of the styled file, but
   the absolute path. This is also reflected in the invisible return value of the 
   function (#522).
+* `style_file()` and friends do not write content back to a file when 
+  styling does not cause any changes in the file. This means the modification 
+  date of files styled is only changed when the content is changed (#532).
 
 ## New features
 

R/io.R

@@ -14,14 +14,15 @@ transform_utf8 <- function(path, fun, write_back = TRUE) {
 }
 
 #' @importFrom rlang with_handlers warn
-transform_utf8_one <- function(path, fun, write_back = write_back) {
+transform_utf8_one <- function(path, fun, write_back) {
   old <- xfun::read_utf8(path)
   with_handlers({
     new <- fun(old)
-    if (write_back) {
+    identical <- identical(unclass(old), unclass(new))
+    if (!identical && write_back) {
       xfun::write_utf8(new, path)
     }
-    !identical(unclass(old), unclass(new))
+    !identical
   }, error = function(e) {
     warn(paste0("When processing ", path, ": ", conditionMessage(e)))
     NA

README.Rmd

@@ -35,14 +35,14 @@ styler can be customized to format code according to other style guides too.
 You can install the package from CRAN:
 
 ```{r, eval = FALSE}
-install.packages("styler") 
+install.packages("styler")
 ```
 
 Or get the development version from GitHub:
 
 ```{r, eval = FALSE} 
-# install.packages("remotes") 
-remotes::install_github("r-lib/styler") 
+# install.packages("remotes")
+remotes::install_github("r-lib/styler")
 ```
 
 ## API
@@ -98,11 +98,11 @@ If you wish to keep alignment as is, you can use `strict = FALSE`:
 ```{r} 
 style_text(
   c(
-    "first  <- 4", 
+    "first  <- 4",
     "second <- 1+1"
   ),
-  strict = FALSE 
-) 
+  strict = FALSE
+)
 ```
 
 This was just the tip of the iceberg. Learn more about customization with the