Fix Type::Page#contents to handle null values in /Contents array

CHANGELOG.md

@@ -29,6 +29,7 @@
   that do not exist
 * [HexaPDF::Font::TrueTypeWrapper] to correctly handle the situation when
   multiple codepoints refer to the same glyph ID
+* [HexaPDF::Type::Page#contents] to handle null values in /Contents array
 
 
 ## 0.47.0 - 2024-09-07

lib/hexapdf/type/page.rb

@@ -358,7 +358,7 @@ def rotate(angle, flatten: false)
       def contents
         Array(self[:Contents]).each_with_object("".b) do |content_stream, content|
           content << " " unless content.empty?
-          content << content_stream.stream
+          content << content_stream.stream if content_stream.kind_of?(Stream)
         end
       end
 

test/hexapdf/type/test_page.rb

@@ -358,6 +358,12 @@ def reset_media_box
       page[:Contents] = [@doc.wrap({}, stream: 'q 10'), @doc.wrap({}, stream: 'w Q')]
       assert_equal('q 10 w Q', page.contents)
     end
+
+    it "handles null objects in the /Contents array" do
+      page = @doc.pages.add
+      page[:Contents] = [@doc.wrap({}, stream: 'q 10'), nil]
+      assert_equal('q 10 ', page.contents)
+    end
   end
 
   describe "contents=" do