Fallback to a temp dir when the home directory is not usable

lib/bundler.rb

@@ -143,8 +143,41 @@ def ruby_scope
       "#{Bundler.rubygems.ruby_engine}/#{Bundler.rubygems.config_map[:ruby_version]}"
     end
 
+    def user_home
+      @user_home ||= begin
+        home = Bundler.rubygems.user_home
+        warning = "Your home directory is not set properly:"
+        if home.nil?
+          warning += "\n * It is not set at all"
+        elsif !File.directory?(home)
+          warning += "\n * `#{home}` is not a directory"
+        elsif !File.writable?(home)
+          warning += "\n * `#{home}` is not writable"
+        else
+          return Pathname.new(home)
+        end
+
+        login = Etc.getlogin || "unknown"
+
+        tmp_home = Pathname.new(Dir.tmpdir).join("bundler", "home", login)
+        begin
+          SharedHelpers.filesystem_access(tmp_home, :write) do |p|
+            FileUtils.mkdir_p(p)
+          end
+        rescue => e
+          warning += "\n\nBundler also failed to create a temporary home directory at `#{tmp_home}`:\n#{e}"
+          raise warning
+        end
+
+        warning += "\n\nBundler will use `#{tmp_home}` as your home directory temporarily"
+
+        Bundler.ui.warn(warning)
+        tmp_home
+      end
+    end
+
     def user_bundle_path
-      Pathname.new(Bundler.rubygems.user_home).join(".bundle")
+      Pathname.new(user_home).join(".bundle")
     end
 
     def home
@@ -403,6 +436,7 @@ def reset!
       @locked_gems = nil
       @bundle_path = nil
       @bin_path = nil
+      @user_home = nil
 
       Plugin.reset!
 

lib/bundler/cli.rb

@@ -36,8 +36,10 @@ def initialize(*args)
     ensure
       self.options ||= {}
       Bundler.settings.cli_flags_given = !options.empty?
+      unprinted_warnings = Bundler.ui.unprinted_warnings
       Bundler.ui = UI::Shell.new(options)
       Bundler.ui.level = "debug" if options["verbose"]
+      unprinted_warnings.each {|w| Bundler.ui.warn(w) }
 
       if ENV["RUBYGEMS_GEMDEPS"] && !ENV["RUBYGEMS_GEMDEPS"].empty?
         Bundler.ui.warn(

lib/bundler/fetcher/compact_index.rb

@@ -61,7 +61,7 @@ def fetch_spec(spec)
       compact_index_request :fetch_spec
 
       def available?
-        user_home = Pathname.new(Bundler.rubygems.user_home)
+        user_home = Bundler.user_home
         return nil unless user_home.directory? && user_home.writable?
         # Read info file checksums out of /versions, so we can know if gems are up to date
         fetch_uri.scheme != "file" && compact_index_client.update_and_parse_checksums!

lib/bundler/gem_helper.rb

@@ -98,7 +98,7 @@ def rubygem_push(path)
         allowed_push_host = @gemspec.metadata["allowed_push_host"]
         gem_command += " --host #{allowed_push_host}" if allowed_push_host
       end
-      unless allowed_push_host || Pathname.new("~/.gem/credentials").expand_path.file?
+      unless allowed_push_host || Bundler.user_home.join(".gem/credentials").file?
         raise "Your rubygems.org credentials aren't set. Run `gem push` to set them."
       end
       sh(gem_command)

lib/bundler/shared_helpers.rb

@@ -39,10 +39,12 @@ def default_bundle_dir
       bundle_dir = find_directory(".bundle")
       return nil unless bundle_dir
 
-      global_bundle_dir = File.join(Bundler.rubygems.user_home, ".bundle")
+      bundle_dir = Pathname.new(bundle_dir)
+
+      global_bundle_dir = Bundler.user_home.join(".bundle")
       return nil if bundle_dir == global_bundle_dir
 
-      Pathname.new(bundle_dir)
+      bundle_dir
     end
 
     def in_bundle?

lib/bundler/ui/shell.rb

@@ -83,6 +83,10 @@ def silence(&blk)
         with_level("silent", &blk)
       end
 
+      def unprinted_warnings
+        []
+      end
+
     private
 
       # valimism

lib/bundler/ui/silent.rb

@@ -2,6 +2,10 @@
 module Bundler
   module UI
     class Silent
+      def initialize
+        @warnings = []
+      end
+
       def add_color(string, color)
         string
       end
@@ -13,6 +17,7 @@ def confirm(message, newline = nil)
       end
 
       def warn(message, newline = nil)
+        @warnings |= [message]
       end
 
       def error(message, newline = nil)
@@ -44,6 +49,10 @@ def trace(message, newline = nil)
       def silence
         yield
       end
+
+      def unprinted_warnings
+        @warnings
+      end
     end
   end
 end