Add check of Dir.home's permission

lib/bundler/cli.rb

@@ -14,6 +14,7 @@ def self.start(*)
       raise e
     ensure
       Bundler::SharedHelpers.print_major_deprecations!
+      Bundler::SharedHelpers.check_home_dir_permissions
     end
 
     def self.dispatch(*)

lib/bundler/shared_helpers.rb

@@ -136,6 +136,10 @@ def print_major_deprecations!
       major_deprecation("Bundler will only support rubygems >= 2.0, you are running #{Bundler.rubygems.version}")
     end
 
+    def check_home_dir_permissions
+      raise PathError, "There was an error while trying to use your home path #{Dir.home}" unless File.writable?(Dir.home)
+    end
+
   private
 
     def find_gemfile

spec/bundler/shared_helpers_spec.rb

@@ -412,4 +412,11 @@ module TargetNamespace
       end
     end
   end
+
+  describe "#check_home_dir_permissions" do
+    it "raises a PathError" do
+      allow(File).to receive(:writable?).with(Dir.home).and_return(false)
+      expect { subject.check_home_dir_permissions }.to raise_error(Bundler::PathError, /There was an error while trying to use your home path/)
+    end
+  end
 end