Parallel styling

.github/workflows/R-CMD-check.yaml

@@ -30,6 +30,7 @@ jobs:
 
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
+      R_STYLER_FUTURE_NO_OVERRIDE: true
       RSPM: ${{ matrix.config.rspm }}
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
       _R_CHECK_FORCE_SUGGESTS_: false

.github/workflows/benchmarking.yaml

@@ -11,6 +11,7 @@ jobs:
 
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
+      R_STYLER_FUTURE_NO_OVERRIDE: true
       RSPM: ${{ matrix.config.rspm }}
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
     steps:

.github/workflows/test-coverage.yaml

@@ -13,6 +13,7 @@ jobs:
     runs-on: macOS-latest
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+      R_STYLER_FUTURE_NO_OVERRIDE: true
     steps:
       - uses: actions/checkout@v2
 

DESCRIPTION

@@ -33,6 +33,8 @@ Suggests:
     data.tree (>= 0.1.6),
     digest,
     dplyr,
+    furrr,
+    future,
     here,
     knitr,
     prettycode,
@@ -56,6 +58,7 @@ Collate:
     'detect-alignment.R'
     'environments.R'
     'expr-is.R'
+    'future.R'
     'indent.R'
     'initialize.R'
     'io.R'

NAMESPACE

@@ -40,6 +40,7 @@ importFrom(purrr,when)
 importFrom(rlang,abort)
 importFrom(rlang,is_empty)
 importFrom(rlang,is_installed)
+importFrom(rlang,local_options)
 importFrom(rlang,seq2)
 importFrom(rlang,warn)
 importFrom(rlang,with_handlers)

R/future.R

@@ -0,0 +1,20 @@
+#' Parallelization of styling
+#'
+#' [style_file()], [style_pkg()] and [style_dir()] leverage the `{future}`
+#' framework for parallelization. To make use of parallel processing, you need
+#' to have the package `{furrr}` installed. In that case, the strategy
+#' [future::multiprocess()] is set temporarily during styling (only if there is
+#' more than two files to style, because of start-up costs of parallelization).
+#' You can prevent this temporary change in the future strategy by setting the
+#' environment variable `R_STYLER_FUTURE_NO_OVERRIDE` to `TRUE` (case ignored). In
+#' that case, the future strategy set before calling styler will be used, if
+#' you have not set any, the future `{framework}` falls back to
+#' [future::sequential()].
+#'
+#' @section Life-cycle:
+#' The parallelization feature is experimental, in particular how its governed
+#' with `R_STYLER_FUTURE_NO_OVERRIDE` and how progress bars are displayed with
+#' `{furrr}`. In the future, most likely the `{progressr}` package will be used
+#' to handle progress bars.
+#' @name styler_future
+NULL

R/transform-files.R

@@ -11,17 +11,44 @@
 #' styling whether or not it was actually changed (or would be changed when
 #' `dry` is not "off").
 #' @keywords internal
+#' @importFrom rlang local_options
 transform_files <- function(files, transformers, include_roxygen_examples, base_indention, dry) {
   transformer <- make_transformer(transformers, include_roxygen_examples, base_indention)
   max_char <- min(max(nchar(files), 0), getOption("width"))
   len_files <- length(files)
   if (len_files > 0L && !getOption("styler.quiet", FALSE)) {
-    cat("Styling ", len_files, " files:\n")
+    cat("Styling ", len_files, " files:\n") # TODO should only have one space between words
+  }
+
+  future_strategy_no_override <- tolower(Sys.getenv("R_STYLER_FUTURE_NO_OVERRIDE", "FALSE")) == "true"
+  if (rlang::is_installed("furrr")) {
+    # only parallelise when furrr is installed
+    if (!future_strategy_no_override && length(files) > 2) {
+      # only override when env not set and more than two files.
+      local_options(future.supportsMulticore.unstable = "quiet")
+      oplan <- future::plan("multisession") # not sure we should use
+
+      # withr::defer() gives C stack overflow on macOS, on.exit not.
+      on.exit(future::plan(oplan), add = TRUE, after = FALSE)
+    }
+    changed <- furrr::future_map_lgl(files, transform_file,
+      fun = transformer, max_char_path = max_char, dry = dry,
+      .progress = TRUE
+    )
+  } else {
+    if (future_strategy_no_override) {
+      rlang::warn(paste(
+        "Environment variable `R_STYLER_FUTURE_NO_OVERRIDE` is not respected",
+        "because package {furrr} is not installed. Falling back to ",
+        "`purrr::map_lgl()` to iterate over files to style instead of",
+        "`furrr::future_map_lgl()`."
+      ))
+    }
+    changed <- map_lgl(files, transform_file,
+      fun = transformer, max_char_path = max_char, dry = dry
+    )
   }
 
-  changed <- map_lgl(files, transform_file,
-    fun = transformer, max_char_path = max_char, dry = dry
-  )
   communicate_summary(changed, max_char)
   communicate_warning(changed, transformers)
   new_tibble(list(file = files, changed = changed), nrow = len_files)

inst/WORDLIST

@@ -58,6 +58,7 @@ filetype
 forcond
 formatter
 funct
+furrr
 gcc
 getChecksum
 getOption
@@ -100,6 +101,7 @@ macOS
 magrittr
 md
 Müller
+multiprocess
 mutli
 na
 navbar
@@ -111,6 +113,8 @@ ourself
 packagemanager
 packrat
 pandoc
+parallelization
+Parallelization
 params
 paren
 parsable
@@ -124,6 +128,7 @@ pre
 precommit
 prefill
 prettycode
+progressr
 PRs
 purrr
 rcmdcheck

tests/testthat/test-future.R

@@ -0,0 +1,53 @@
+path_rel <- c(
+  "dirty-sample-with-scope-tokens.R",
+  "dirty-sample-with-scope-spaces.R",
+  "clean-sample-with-scope-tokens.R"
+)
+
+path_dir <- file.path(
+    "public-api", "xyzdir-dirty", path_rel
+)
+
+test_that("can style in parallel when no strategy is set and overriding is deactivated", {
+  withr::local_envvar("R_STYLER_FUTURE_NO_OVERRIDE" = "TRUE")
+  expect_match(
+    catch_style_file_output(path_dir),
+    'Styling +3',
+    all = FALSE
+  )
+})
+
+test_that("can style in parallel when no strategy is set and overriding is not deactivated", {
+  withr::local_envvar("R_STYLER_FUTURE_NO_OVERRIDE" = "FALSE")
+  expect_match(
+    catch_style_file_output(path_dir),
+    'Styling +3',
+    all = FALSE
+  )
+})
+
+test_that("can style in parallel when no strategy is set", {
+
+  expect_match(
+    catch_style_file_output(path_dir),
+    'Styling +3',
+    all = FALSE
+  )
+})
+
+test_that("can style in parallel when strategy is set", {
+  future::plan('sequential')
+  expect_match(
+    catch_style_file_output(path_dir),
+    'Styling +3',
+    all = FALSE
+  )
+})
+
+test_that("with fewer than two files, the plan is not modified", {
+  expect_match(
+    catch_style_file_output(path_dir[1]),
+    'Styling +1',
+    all = FALSE
+  )
+})