Rtools: fall back to R CMD config, path, registry

If we do not find Rtools44, Rtools43 or Rtools42 at
the usual places or where they should be, e.g. because
they were not installed from an installer, but from
.zst files.

NEWS.md

@@ -1,5 +1,8 @@
 # pkgbuild (development version)
 
+* pkgbuild now does a better job at finding Rtools 4.3 and 4.4 if they
+  were not installed from an installer.
+
 # pkgbuild 1.4.4
 
 * pkgbuild now supports R 4.4.x and Rtools44 (#183).

R/rtools-metadata.R

@@ -75,6 +75,11 @@ version_info <- list(
   ),
   "4.3" = list(
     version_min = "4.3.0",
+    version_max = "4.3.99",
+    path = "usr/bin"
+  ),
+  "4.4" = list(
+    version_min = "4.4.0",
     version_max = "99.99.99",
     path = "usr/bin"
   ),

R/rtools-path.R

@@ -14,6 +14,10 @@ scan_path_for_rtools <- function(debug = FALSE) {
 
   # We have a candidate install_path
   install_path <- dirname(dirname(ls_path))
+  # ls is one more directory down on recent rtools
+  if (basename(install_path) == "usr") {
+    install_path <- dirname(install_path)
+  }
 
   gcc_path <- Sys.which("gcc")
   if (debug) {

R/rtools.R

@@ -40,7 +40,6 @@ has_rtools <- function(debug = FALSE) {
       rtools_path_set(rtools(rtools44_aarch64_home, "4.4"))
       return(TRUE)
     }
-    return(FALSE)
   }
 
   # R 4.4.0 or later
@@ -53,11 +52,11 @@ has_rtools <- function(debug = FALSE) {
       rtools_path_set(rtools(rtools44_home, "4.4"))
       return(TRUE)
     }
-    return(FALSE)
   }
 
   # R 4.3.0 or later on ARM64
-  if (getRversion() >= "4.3.0" && grepl("aarch", R.version$platform)) {
+  if (getRversion() >= "4.3.0" && getRversion() < "4.4.0" &&
+      grepl("aarch", R.version$platform)) {
     rtools43_aarch64_home <- Sys.getenv("RTOOLS43_AARCH64_HOME", "C:\rtools43-aarch64")
     if (file.exists(file.path(rtools43_aarch64_home, "usr", "bin"))) {
       if (debug) {
@@ -66,11 +65,10 @@ has_rtools <- function(debug = FALSE) {
       rtools_path_set(rtools(rtools43_aarch64_home, "4.3"))
       return(TRUE)
     }
-    return(FALSE)
   }
 
   # R 4.3.0 or later
-  if (getRversion() >= "4.3.0") {
+  if (getRversion() >= "4.3.0" && getRversion() < "4.4.0") {
     rtools43_home <- Sys.getenv("RTOOLS43_HOME", "C:\\rtools43")
     if (file.exists(file.path(rtools43_home, "usr", "bin"))) {
       if (debug) {
@@ -79,25 +77,26 @@ has_rtools <- function(debug = FALSE) {
       rtools_path_set(rtools(rtools43_home, "4.3"))
       return(TRUE)
     }
-    return(FALSE)
   }
 
   # R 4.2.x or later and ucrt?
-  ucrt <- is_ucrt()
-  if (ucrt) {
-    rtools42_home <- Sys.getenv("RTOOLS42_HOME", "C:\\rtools42")
-    if (file.exists(file.path(rtools42_home, "usr", "bin"))) {
-      if (debug) {
-        cat("Found in Rtools 4.2 installation folder\n")
+  if (getRversion() >= "4.2.0" && getRversion() < "4.3.0") {
+    ucrt <- is_ucrt()
+    if (ucrt) {
+      rtools42_home <- Sys.getenv("RTOOLS42_HOME", "C:\\rtools42")
+      if (file.exists(file.path(rtools42_home, "usr", "bin"))) {
+        if (debug) {
+          cat("Found in Rtools 4.2 installation folder\n")
+        }
+        rtools_path_set(rtools(rtools42_home, "4.2"))
+        return(TRUE)
       }
-      rtools_path_set(rtools(rtools42_home, "4.2"))
-      return(TRUE)
     }
   }
 
   # In R 4.0 we can use RTOOLS40_HOME, recent versions of Rtools40 work fine
   # with ucrt as well, currently.
-  if (is_R4()) {
+  if (getRversion() >= "4.0.0" && getRversion() < "4.3.0") {
     rtools40_home <- Sys.getenv("RTOOLS40_HOME", "C:\\rtools40")
     fld <- if (ucrt) "ucrt64" else "usr"
     if (file.exists(file.path(rtools40_home, fld, "bin"))) {