AttributeError: 'NumberObject' object has no attribute 'indirect_reference'

[jflalande]

An exception occurs when merging the joint pdf with itself:

  File "/home/jf/.local/lib/python3.10/site-packages/pypdf/_writer.py", line 2863, in merge
    elif dest["/Page"].indirect_reference.idnum in srcpages:
AttributeError: 'NumberObject' object has no attribute 'indirect_reference'

Environment

Which environment were you using when you encountered the problem?

$ python3 -m platform
Linux-5.19.0-35-generic-x86_64-with-glibc2.35
$ python3 -c "import pypdf;print(pypdf.__version__)"
3.10.0

Code + PDF

This is a minimal, complete example that shows the issue:

from pypdf import PdfWriter

merger = PdfWriter()
for pdf in ["tmp.pdf", "tmp.pdf"]:
    merger.append(pdf)

merger.write("merged-pdf.pdf")
merger.close()

Share here the PDF file(s) that cause the issue. The smaller they are, the
better. Let us know if we may add them to our tests!

Traceback

This is the complete Traceback I see:

python3 test.py 
Traceback (most recent call last):
  File "/home/jf/CentraleSupelec/Mention_Cyber/syllabus/test.py", line 5, in <module>
    merger.append(pdf)
[tmp.pdf](https://github.com/py-pdf/pypdf/files/11799685/tmp.pdf)

  File "/home/jf/.local/lib/python3.10/site-packages/pypdf/_writer.py", line 2767, in append
    self.merge(
  File "/home/jf/.local/lib/python3.10/site-packages/pypdf/_utils.py", line 439, in wrapper
    return func(*args, **kwargs)
  File "/home/jf/.local/lib/python3.10/site-packages/pypdf/_writer.py", line 2863, in merge
    elif dest["/Page"].indirect_reference.idnum in srcpages:
AttributeError: 'NumberObject' object has no attribute 'indirect_reference'

tmp.pdf

[pubpub-zz]

solution in progress

[pubpub-zz]

actually the solution is in the pipe since a month.
@MartinThoma should merge it soon (he has already merged #1856 required and resolved conflicts)