Mark other mutating methods in Entry as dirty.

Also, remove `Entry#extra=` as it makes no sense (and wasn't even being
tested).

And remove slightly odd test that was assuming an archive would not be
changed if its utime was changed - even if it was being changed back
immediately. This test was merely confirming that we weren't catching
timestamp changes correctly.

.rubocop_todo.yml

@@ -20,7 +20,7 @@ Lint/MissingSuper:
 # Offense count: 5
 # Configuration parameters: CountComments, CountAsOne.
 Metrics/ClassLength:
-  Max: 620
+  Max: 630
 
 # Offense count: 21
 # Configuration parameters: IgnoredMethods.

lib/zip/entry.rb

@@ -118,14 +118,6 @@ def incomplete?
       gp_flags & 8 == 8
     end
 
-    def extra=(field)
-      @extra = if field.nil?
-                 ExtraField.new
-               else
-                 field.kind_of?(ExtraField) ? field : ExtraField.new(field.to_s)
-               end
-    end
-
     def time
       if @extra['UniversalTime'] && !@extra['UniversalTime'].mtime.nil?
         @extra['UniversalTime'].mtime
@@ -141,6 +133,7 @@ def time
     alias mtime time
 
     def time=(value)
+      @dirty = true
       unless @extra.member?('UniversalTime') || @extra.member?('NTFS')
         @extra.create('UniversalTime')
       end
@@ -157,6 +150,7 @@ def compression_method
     end
 
     def compression_method=(method)
+      @dirty = true
       @compression_method = (@ftype == :directory ? STORED : method)
     end
 

test/filesystem/file_nonmutating_test.rb

@@ -152,15 +152,6 @@ def test_join
     assert_equal('a/b/c/d', @zip_file.file.join('a', 'b', 'c', 'd'))
   end
 
-  def test_utime
-    t_now = ::Zip::DOSTime.now
-    t_bak = @zip_file.file.mtime('file1')
-    @zip_file.file.utime(t_now, 'file1')
-    assert_equal(t_now, @zip_file.file.mtime('file1'))
-    @zip_file.file.utime(t_bak, 'file1')
-    assert_equal(t_bak, @zip_file.file.mtime('file1'))
-  end
-
   def assert_always_false(operation)
     assert(!@zip_file.file.send(operation, 'noSuchFile'))
     assert(!@zip_file.file.send(operation, 'file1'))