make error more like NameError, since this is one

lib/bundler/dsl.rb

@@ -161,14 +161,9 @@ def env(name)
     end
 
     def method_missing(name, *args)
-      call = caller[0].split ':'
-      line = call[1].to_i
-      lines = ([0, line - 3].max)..line + 2
-      content = Bundler.read_file(call[0]).lines.to_a[lines].join('  ').strip
-
-      raise GemfileError, "The Gemfile doesn't support the method `#{name}`.\n" \
-                          "Please check your Gemfile's syntax at line #{line}:\n\n" \
-                          "  #{content}\n"
+      location = caller[0].split(':')[0..1].join(':')
+      raise GemfileError, "Undefined local variable or method `#{name}' for Gemfile\n" \
+        "        from #{location}"
     end
 
   private

spec/bundler/dsl_spec.rb

@@ -22,12 +22,11 @@
 
   describe '#method_missing' do
     it 'should raise an error for unknown DSL methods' do
-      dsl = Bundler::Dsl.new
-      dsl.stub(:caller => ['Gemfile:3'])
-      Bundler.should_receive(:read_file).with('Gemfile').and_return("source :rubygems\ngemspec\nunknown")
-
-      error_msg = "The Gemfile doesn't support the method `unknown`.\nPlease check your Gemfile's syntax at line 3:\n\n  source :rubygems\n  gemspec\n  unknown\n"
-      lambda { dsl.unknown }.should raise_error(Bundler::GemfileError, error_msg)
+      Bundler.should_receive(:read_file).with("Gemfile").and_return("unknown")
+      error_msg = "Undefined local variable or method `unknown'" \
+        " for Gemfile\\s+from Gemfile:1"
+      lambda{ subject.eval_gemfile("Gemfile") }.
+        should raise_error(Bundler::GemfileError, Regexp.new(error_msg))
     end
   end