Display reason to require sudo

This is useful for non-interactive installation with bundler.

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/bundler.rb b/lib/bundler.rb
index 9944ebd051..ae26dea26c 100644
--- a/lib/bundler.rb
+++ b/lib/bundler.rb
@@ -367,6 +367,10 @@ EOF
         # if any directory is not writable, we need sudo
         files = [path, bin_dir] | Dir[bundle_path.join("build_info/*").to_s] | Dir[bundle_path.join("*").to_s]
         sudo_needed = files.any? {|f| !File.writable?(f) }
+        if sudo_needed
+          unwritable_files = files.reject {|f| File.writable?(f) }
+          Bundler.ui.warn "Following files may not be writable, so sudo is needed: #{unwritable_files.map(&:to_s).join(',')}"
+        end
       end
 
       @requires_sudo_ran = true