Helpful message when build fails for long paths

R/install.R

@@ -91,13 +91,32 @@ safe_build_package <- function(pkgdir, build_opts, dest_path, quiet, use_pkgbuil
 
     pkgdir <- normalizePath(pkgdir)
 
+    message("Running `R CMD build`...")
     in_dir(dest_path, {
       with_envvar(env, {
-        output <- rcmd("build", c(build_opts, shQuote(pkgdir)), quiet = quiet)
+        output <- rcmd("build", c(build_opts, shQuote(pkgdir)), quiet = quiet,
+                       fail_on_status = FALSE)
       })
     })
 
-    file.path(dest_path, sub("^[*] building[^[:alnum:]]+([[:alnum:]_.]+)[^[:alnum:]]+$", "\\1", output[length(output)]))
+    if (output$status != 0) {
+      cat("STDOUT:\n")
+      cat(output$stdout, sep = "\n")
+      cat("STDERR:\n")
+      cat(output$stderr, sep = "\n")
+      if (sys_type() == "windows" &&
+          any(grepl("over-long path length", output$stderr))) {
+        message(
+          "\nIt seems that this package contains files with very long paths.\n",
+          "This is not supported on most Windows versions. Please contant the\n",
+          "package authors and tell them about this. See this GitHub issue\n",
+          "for more details: https://github.com/r-lib/remotes/issues/84\n")
+      }
+      stop(sprintf("Failed to `R CMD build` package, try `build = FALSE`."),
+           call. = FALSE)
+    }
+
+    file.path(dest_path, sub("^[*] building[^[:alnum:]]+([[:alnum:]_.]+)[^[:alnum:]]+$", "\\1", output$stdout[length(output$stdout)]))
   }
 }
 

R/utils.R

@@ -9,7 +9,7 @@ viapply <- function(X, FUN, ..., USE.NAMES = TRUE) {
   vapply(X, FUN, integer(1L), ..., USE.NAMES = USE.NAMES)
 }
 
-rcmd <- function(cmd, args, path = R.home("bin"), quiet) {
+rcmd <- function(cmd, args, path = R.home("bin"), quiet, fail_on_status = TRUE) {
   if (os_type() == "windows") {
     real_cmd <- file.path(path, "Rcmd.exe")
     args <- c(cmd, args)
@@ -18,19 +18,25 @@ rcmd <- function(cmd, args, path = R.home("bin"), quiet) {
     args <- c("CMD", cmd, args)
   }
 
-  outfile <- tempfile()
-  status <- system2(real_cmd, args, stderr = NULL, stdout = outfile)
-  out <- readLines(outfile, warn = FALSE)
+  stdoutfile <- tempfile()
+  stderrfile <- tempfile()
+  on.exit(unlink(c(stdoutfile, stderrfile), recursive = TRUE), add = TRUE)
+  status <- system2(real_cmd, args, stderr = stderrfile, stdout = stdoutfile)
+  out <- tryCatch(readLines(stdoutfile, warn = FALSE), error = function(x) "")
+  err <- tryCatch(readLines(stderrfile, warn = FALSE), error = function(x) "")
 
-  if (status != 0) {
+  if (fail_on_status && status != 0) {
+    cat("STDOUT:\n")
     cat(out, sep = "\n")
+    cat("STDERR:\n")
+    cat(err, sep = "\n")
     stop(sprintf("Error running '%s' (status '%i')", cmd, status), call. = FALSE)
   }
   if (!quiet) {
     cat(out, sep = "\n")
   }
 
-  out
+  list(stdout = out, stderr = err, status = status)
 }
 
 is_bioconductor <- function(x) {

tests/testthat/test-install.R

@@ -39,7 +39,7 @@ test_that("safe_build_package fails appropriately without pkgbuild", {
   capture.output(
     expect_error(fixed = TRUE,
     safe_build_package(test_path("invalidpkg"), build_opts = opts , out, quiet = TRUE, use_pkgbuild = FALSE),
-    "Error running 'build' (status '1')"
+    "Failed to `R CMD build` package"
   ))
 })