Prompt to install build tools when needed.

Closes #488

NEWS.md

@@ -33,6 +33,10 @@
 
 ## Other minor improvements and bug fixes
 
+* If you're using Rstudio, and you you're trying to build a binary package
+  without the necessary build tools, Rstudio will prompt to download and
+  install the right thing. (#488)
+
 * devtools no longer runs commands with `LC_ALL=C` - this no longer seems
   to be necessary (#507).
 

R/build.r

@@ -28,6 +28,8 @@
 build <- function(pkg = ".", path = NULL, binary = FALSE, vignettes = TRUE,
                   args = NULL, quiet = FALSE) {
   pkg <- as.package(pkg)
+  check_build_tools(pkg)
+
   if (is.null(path)) {
     path <- dirname(pkg$path)
   }

R/has-devel.r

@@ -23,3 +23,16 @@ has_devel <- function() {
   stopifnot(.C(dll$foo, 0L)[[1]] == 1L)
   TRUE
 }
+
+check_build_tools <- function(pkg = ".") {
+  pkg <- as.package(pkg)
+  if (!file.exists(pkg$path, "src")) return(TRUE)
+
+  check <- getOption("buildtools.check", NULL)
+  if (!is.null(check)) {
+    check("Installing R package from source")
+  } else {
+    # Outside of Rstudio and don't have good heuristic
+    TRUE
+  }
+}

R/install.r

@@ -53,6 +53,7 @@ install <- function(pkg = ".", reload = TRUE, quick = FALSE, local = TRUE,
                     threads = getOption("Ncpus", 1)) {
 
   pkg <- as.package(pkg)
+  check_build_tools(pkg)
 
   if (!quiet) message("Installing ", pkg$package)
   install_deps(pkg, dependencies = dependencies, threads = threads)