BUG: Merge pages without resources (#2150)

closes #2147

Author: pubpub-zz

pypdf/_page.py

@@ -1183,8 +1183,13 @@ def _merge_page_writer(
         pdf = self.indirect_reference.pdf
 
         rename = {}
+        if PG.RESOURCES not in self:
+            self[NameObject(PG.RESOURCES)] = DictionaryObject()
         original_resources = cast(DictionaryObject, self[PG.RESOURCES].get_object())
-        page2resources = cast(DictionaryObject, page2[PG.RESOURCES].get_object())
+        if PG.RESOURCES not in page2:
+            page2resources = DictionaryObject()
+        else:
+            page2resources = cast(DictionaryObject, page2[PG.RESOURCES].get_object())
 
         for res in (
             RES.EXT_G_STATE,

tests/test_page.py

@@ -1227,6 +1227,16 @@ def create_stamp_pdf() -> BytesIO:
     )
 
 
+def test_merge_with_no_resources():
+    """Test for issue #2147"""
+    writer = PdfWriter()
+    p0 = writer.add_blank_page(900, 1200)
+    del p0["/Resources"]
+    p1 = writer.add_blank_page(900, 1200)
+    del p1["/Resources"]
+    writer.pages[0].merge_page(p1)
+
+
 def test_get_contents_from_nullobject():
     """Issue #2157"""
     writer = PdfWriter()