apacheGH-36638: [R] Error with create_package_with_all_dependencies()…

… on Windows (apache#37226)

### Rationale for this change

Fix path to directory which stops `create_package_with_all_dependencies()` working on Windows

### What changes are included in this PR?

Character replacement in the script to ensure that on Windows, wsl-comaptible path is used and paths are normalised.

### Are these changes tested?

I tested it locally myself and it works - there are no tests for this function.

### Are there any user-facing changes?

Nope
* Closes: apache#36638

Authored-by: Nic Crane <[email protected]>
Signed-off-by: Nic Crane <[email protected]>

r/R/install-arrow.R

@@ -215,19 +215,25 @@ create_package_with_all_dependencies <- function(dest_file = NULL, source_file =
   untar_dir <- tempfile()
   on.exit(unlink(untar_dir, recursive = TRUE), add = TRUE)
   utils::untar(source_file, exdir = untar_dir)
-  tools_dir <- file.path(untar_dir, "arrow/tools")
+  tools_dir <- file.path(normalizePath(untar_dir, winslash = "/"), "arrow/tools")
   download_dependencies_sh <- file.path(tools_dir, "download_dependencies_R.sh")
   # If you change this path, also need to edit nixlibs.R
   download_dir <- file.path(tools_dir, "thirdparty_dependencies")
   dir.create(download_dir)
   download_script <- tempfile(fileext = ".R")
+
+  if (isTRUE(Sys.info()["sysname"] == "Windows")) {
+    download_dependencies_sh <- wslify_path(download_dependencies_sh)
+  }
+
   parse_versions_success <- system2(
     "bash", c(download_dependencies_sh, download_dir),
     stdout = download_script,
     stderr = FALSE
   ) == 0
+
   if (!parse_versions_success) {
-    stop("Failed to parse versions.txt")
+    stop(paste("Failed to parse versions.txt; view ", download_script, "for more information", collapse = ""))
   }
   # `source` the download_script to use R to download all the dependency bundles
   source(download_script)
@@ -250,3 +256,14 @@ create_package_with_all_dependencies <- function(dest_file = NULL, source_file =
   }
   invisible(dest_file)
 }
+
+# Convert a Windows path to a WSL path
+# e.g. wslify_path("C:/Users/user/AppData/") returns "/mnt/c/Users/user/AppData"
+wslify_path <- function(path) {
+  m <- regexpr("[A-Z]:/", path)
+  drive_expr <- regmatches(path, m)
+  drive_letter <- strsplit(drive_expr, ":/")[[1]]
+  wslified_drive <- paste0("/mnt/", tolower(drive_letter))
+  end_path <- strsplit(path, drive_expr)[[1]][-1]
+  file.path(wslified_drive, end_path)
+}