Problem with closing PDF file saved by PyPDF2

[Kaemer1645]

I'm create PDF file using PyPDF2. After that when I'm oppening this file with Adobe Acrobat and I would like to close it. The window appears with messege like "Would you like to save this file?"
I haven't got this problem with previous versions of PyPDF2.

Environment

$ python -m platform
Windows-10-10.0.19044-SP0

$ python -c "import PyPDF2;print(PyPDF2.__version__)"
2.1.0

Code

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

from PyPDF2 import PdfFileWriter
import os

c_dir = os.getcwd()
path = os.path.join(c_dir,'test_2.pdf')
pdf = PdfFileWriter()
pdf.addBlankPage(100, 100)
pdf.write(open(path, 'wb'))

PDF

test_2.pdf

[Kaemer1645]

I checked which version work properly and that is:
pypdf==1.27.2
pypdf==1.27.3
pypdf==1.27.4
pypdf==1.27.5
everythng above work wrong.

[MartinThoma]

Thank you for reporting the issue 🙏

I don't quite understand: Which versions work and which are broken?

[MartinThoma]

Please note that pdf.write(open(path, 'wb')) is not good style. This leaves the file handle open. Instead, you should write:

with open(path, "wb") as fh:
    pdf.write(fh)

After the with-block, the file handle fh will be closed automatically by Python. I'm uncertain if this is related.

[Kaemer1645]

I know use with style is more pythonic but using "with" it didn't work too.

The versions which work is
pypdf==1.27.2
pypdf==1.27.3
pypdf==1.27.4
pypdf==1.27.5
but every above this versions like 1.27.6 1.27.8... didn't work.

Code

# from PyPDF2 import PdfFileWriter
import os

c_dir = os.getcwd()
path = os.path.join(c_dir, 'test_10.pdf')
pdf = PdfFileWriter()
pdf.addBlankPage(100, 100)
file = open(path, 'wb')
pdf.write(file)
file.close()

pdf2 = PdfFileWriter()
path2 = os.path.join(c_dir, 'test_11.pdf')
with open(path2, "wb") as fh:
    pdf2.addBlankPage(100, 100)
    pdf2.write(fh)

Both work wrong on version >= 1.27.6

[pubpub-zz]

@Kaemer1645 ,
Can you try to see what is the result of analysis of the generated pdf to have a better understanding (ex not tried)
https://www.datalogics.com/products/pdf-tools/pdf-checker/

[Kaemer1645]

report_1.27.6.txt
report_1.27.5.txt

[pubpub-zz]

@Kaemer1645,
may I bother you a little more : can you post the output with version 1.27.5 ? thx

[pubpub-zz]

@MartinThoma ,
Looking carefully to the generated file, I can see an AcroForm field where Fields(identified as mandatory) is missing. When I manually delete the field (not the object which remains unlinked to the root object after file writing), the pdf file did not asked for saving at closure. can you double check and investigate about any change about this field ?

[Kaemer1645]

@pubpub-zz of course I can
test_1_27_6.pdf
test_1_27_5.pdf

[MartinThoma]

@pubpub-zz I didn't have the time to look into that since yesterday, but what popped into my mind is #414 (introduced in 1.27.6)

[mawr-san]

Hi there,
Got the exact same problem after updating an old version of PyPDF2. My script is only merging files.
Here my actual versions :

PS E:\> python --version
Python 3.10.5
PS E:\> python -m platform
Windows-10-10.0.19044-SP0
PS E:\> python -c "import PyPDF2;print(PyPDF2.__version__)"
2.1.0

If this could help, when I try to merge the problematic files, it return this messages at some point :
C:\Program Files\Python310\lib\site-packages\PyPDF2_writer.py:875: UserWarning: Unable to resolve [IndirectObject: IndirectObject(96, 0)], returning NullObject instead warnings.warn(

[pubpub-zz]

The issue comes from #412 (refer to discussion #355)

when /NeedAppearances is set to true, it asks for saving

My current proposal would be to remove call to set_need_appearances_writer() in __init__() and just call it in update_page_form_field_values()

@MartinThoma , @MasterOdin your opinion ?

[pubpub-zz]

@Kaemer1645, if you want for the moment, you may add

from PyPDF2.generic import NameObject,BooleanObject
pdf._root_object["/AcroForm"][NameObject("/NeedAppearances")] = BooleanObject(False)

before calling pdf.write(...)

[MartinThoma]

@mawr-san / @Kaemer1645 Would you please check if the following PDF also has the mentioned issue:

potentially-solved.pdf

If the bug doesn't appear with that PDF, we can merge #970 (going with the fix proposed by @pubpub-zz )

[Kaemer1645]

@MartinThoma everything works fine!

[MartinThoma]

Nice! Thanks for confirming!

The fix is now in the main branch on GitHub and I'll create a new release on PyPI some time tomorrow :-)