BUG: Fixed merge page bug issue with _markup_annotations objects

pypdf/_page.py

@@ -495,6 +495,18 @@ class PageObject(DictionaryObject):
 
     original_page: "PageObject"  # very local use in writer when appending
 
+    def __new__(cls, *args: tuple[Any], **kwargs: dict[Any, Any]) -> "PageObject":
+        """__new__ used here to make sure instance.pdf attribute
+        is set. related to #3467.
+        """
+        instance = super().__new__(cls)
+
+        instance.pdf = None
+        instance.inline_images = None
+        instance.indirect_reference = None
+
+        return instance
+
     def __init__(
         self,
         pdf: Optional[PdfCommonDocProtocol] = None,

pypdf/generic/_data_structures.py

@@ -293,7 +293,9 @@ def clone(
         visited: set[tuple[int, int]] = set()  # (idnum, generation)
         d__ = cast(
             "DictionaryObject",
-            self._reference_clone(self.__class__(), pdf_dest, force_duplicate),
+            self._reference_clone(self.__new__(self.__class__), pdf_dest, force_duplicate),
+            # self.__new__(self.__class__) because we want instance of type __class__,
+            # where we copy values into later below
         )
         if ignore_fields is None:
             ignore_fields = []

tests/generic/test_files.py

@@ -8,6 +8,7 @@
 import pytest
 
 from pypdf import PdfReader, PdfWriter
+from pypdf.annotations._markup_annotations import Polygon
 from pypdf.constants import AFRelationship
 from pypdf.errors import PdfReadError, PyPdfError
 from pypdf.generic import (
@@ -575,3 +576,27 @@ def test_embedded_file__order():
         "test.txt", attachment4.pdf_object.indirect_reference,
         "xyz.txt", attachment3.pdf_object.indirect_reference,
     ]
+
+
+def test_merge_page_with_annotation():
+    # added and adapted from issue #3467
+    writer = PdfWriter()
+    writer2 = PdfWriter()
+    writer.add_blank_page(100, 100)
+    writer2.add_blank_page(100, 100)
+
+    annotation = Polygon(
+        vertices=[(50, 550), (200, 650), (70, 750), (50, 700)],
+    )
+
+    writer.add_annotation(0, annotation)
+
+    page1 = writer.pages[0]
+    page2 = writer2.pages[0]
+    page2.merge_page(page1)
+
+    assert page2.annotations[0].get_object()["/Type"] == annotation["/Type"]
+    assert page2.annotations[0].get_object()["/Subtype"] == annotation["/Subtype"]
+    assert page2.annotations[0].get_object()["/Vertices"] == annotation["/Vertices"]
+    assert page2.annotations[0].get_object()["/IT"] == annotation["/IT"]
+    assert page2.annotations[0].get_object()["/Rect"] == annotation["/Rect"]