Calling check() after generate_appearance_streams()

[rxw1]

Hello,

not sure if this is expected behaviour:

Calling check() after generate_appearance_streams() seems to remove the effect of setting pdf.Root.AcroForm.NeedAppearances = True and may lead to the form field contents not being rendered.

Calling check() before generate_appearance_streams() or not calling generate_appearance_streams() does not have that consequence.

A somewhat minimal example:

from pikepdf import Pdf, Name

annotation_data = {
    "Text1": "Hello",
    "Text2": "World",
}

with Pdf.open("example1.pdf") as pdf:
    for page in pdf.pages:
        annots = page.Annots
        if annots is not None:
            for annot in annots.as_list():
                key = str(annot.T)
                if annot.FT == Name("/Tx"):
                    if key in (annotation_data or {}):
                        value = annotation_data.get(key)
                        if value and value.strip():
                            annot.V = value
                            annot.Ff = 1

    pdf.Root.AcroForm.NeedAppearances = True
    pdf.generate_appearance_streams()
    pdf.check()

    pdf.save('example1-modified.pdf')

example1.pdf

Best regards