Simply duplicate fillable pdf but can't get fields() from the new one.

[remove158]

I just simply duplicate fillable pdf form using PdfWriter.add_page. After that I open the new one with PdfReader. Now the new pdf return None from reader.get_fields()

1. My first fillable form has many fields when I use reader.get_fields()
2. The new one return None (or empty dict {} in case I update the old one with writer.update_page_form_field_values(writer.pages[0], {}) before saving)

Environment

Which environment were you using when you encountered the problem?

pypdf2 = "^3.0.1"
python = "^3.11"

Code + PDF

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

from PyPDF2 import PdfReader, PdfWriter

source =  'tests/jt32.pdf'
out = 'output.pdf'
reader = PdfReader(source)
writer = PdfWriter()

fields = reader.get_fields()
print(fields)
for i in range(len(reader.pages)):
    writer.add_page(reader.pages[i])
    

with open(out, 'wb') as output_file:
    writer.write(output_file)

reader_2 = PdfReader(out)
print(reader_2.get_fields())

pdf: https://cdn.discordapp.com/attachments/1082352569973751868/1096945829291503676/jt32.pdf

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:
Noting error !!

[MartinThoma]

PyPDF2 is deprecated. Use pypdf.

[remove158]

PyPDF2 is deprecated. Use pypdf.

Thanks for the quick reply, I've tried both pypdf, pypdf2, it doesn't matter which version. Both versions produce the same results.

python = "^3.11"
pypdf = "^3.7.1"
pypdf2 = "^3.0.1"

[pubpub-zz]

fields are part of the PDF structure not pages. try append() adding all the pages at once instead of add_page()

[MartinThoma]

Thanks for the quick reply, I've tried both pypdf, pypdf2, it doesn't matter which version. Both versions produce the same results.

That is not the point. When you use deprecated software you cannot expect any support. Development will continue with pypdf. The project is called pypdf, not PyPDF2. We don't have the resources to maintain two projects. By directly using the maintained project you will get better results (at least in some cases, see CHANGELOG) and it helps us to spend our time more effectively.

[neversphere]

fields are part of the PDF structure not pages. try append() adding all the pages at once instead of add_page()

The sample code in the docs doesn't mention this (https://pypdf.readthedocs.io/en/stable/user/forms.html?highlight=Interactions%20with%20PDF%20Forms). Does it need to be updated?

[MartinThoma]

Adding some information there is certainly a good idea! Do you want to open a PR @neversphere ? 😇

[neversphere]

#1806