Radio buttons do not retain values when filling template (when viewed in Adobe Acrobat)

[melvsparks]

I am trying to programmatically fill in a template.pdf that needs to have viewing support with Adobe Acrobat. The files look just fine in other PDF viewers.

I'm trying to do the following

1. Set the "Policy number" text field - This works perfectly
2. Retain the enabled "New Enrollment" radio button - (see attempts 1-3 in the comments below) The generated PDF always has a disabled Radio button
3. Update the "Gender" radio button to Female - This value also doesn't show as enabled in the generated pdf

I looked at the underlying code for the PDFs and they appear to be all set correct (/V, /DV, /AS, etc).

Environment

Which environment were you using when you encountered the problem?
Opened the final pdf in windows and MacOS adobe acrobat

$ python -m platform
Windows-11-10.0.26100-SP0

$ python -c "import pypdf;print(pypdf._debug_versions)"
pypdf==6.4.0, crypt_provider=('local_crypt_fallback', '0.0.0'), PIL=11.3.0

$ python repro_issue.py
Created: repro_adobe_issue.pdf

Code + PDF

Template: TemplateReproBug.pdf
Output: repro_adobe_issue.pdf

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

# Filename: repro_issue.py
from pypdf import PdfReader, PdfWriter
from pypdf.generic import BooleanObject, NameObject

inp = "src/scripts/carriers/UHCAZ/TemplateReproBug.pdf"
out = "repro_adobe_issue.pdf"

reader = PdfReader(inp, strict=False)

if "/AcroForm" in reader.trailer["/Root"]:
    reader.trailer["/Root"]["/AcroForm"].update(
        {NameObject("/NeedAppearances"): BooleanObject(True)}
    )

writer = PdfWriter()
writer.append(reader)

field_dictionary = {
    "Policy Number": "ABC123456",  # Set Policy Number field
    "Gender 01": "/0",  # Gender - select first option (kid 0)
    # What doesn't work when trying to retain the New Enrollment radio button thats selected in the template 
    # 1. Leaving out 'Radio Button 3' entirely
    # 2. Setting 'Radio Button 3' to '/0' programatically: ```'Radio Button 3': '/0'```
    # 3. See below for manual setting of /V, /DV, and /AS
}


writer.update_page_form_field_values(writer.pages[0], field_dictionary)

# 3. Ensure proper /V, /DV, and /AS for radio button Adobe compatibility
fields = writer.pages[0].get("/Annots")
if fields:
    for field_ref in fields:
        field = field_ref.get_object()
        field_name = field.get("/T")

        if field_name == "Radio Button 3":
            # Set parent /V and /DV
            field.update(
                {
                    NameObject("/V"): NameObject("/0"),
                    NameObject("/DV"): NameObject("/0"),
                }
            )
            # Set child /AS for selected kid
            kids = field.get("/Kids")
            if kids:
                for kid_ref in kids:
                    kid = kid_ref.get_object()
                    kid.update({NameObject("/AS"): NameObject("/0")})
                    break  # Only set first kid to selected

        elif field_name == "Gender 01":
            # Set parent /V and /DV for gender (use /0 for first option)
            field.update(
                {
                    NameObject("/V"): NameObject("/0"),
                    NameObject("/DV"): NameObject("/0"),
                }
            )
            # Set child /AS for selected kid (kid 0 gets /0, others get /Off)
            kids = field.get("/Kids")
            if kids:
                for i, kid_ref in enumerate(kids):
                    kid = kid_ref.get_object()
                    if i == 0:  # First kid gets selected
                        kid.update({NameObject("/AS"): NameObject("/0")})
                    else:  # Other kids get Off
                        kid.update({NameObject("/AS"): NameObject("/Off")})

with open(out, "wb") as fp:
    writer.write(fp)

print(f"Created: {out}")

TemplateReproBug.pdf

Screenshots

TemplateReproBug.pdf

repro_adobe_issue.pdf

The relevant fields for this post that are being updated are highlighted in red

[stefan6419846]

Have you tried saving the PDF with the corresponding field set on Acrobat? Being able to compare the output of our approach with the one of Acrobat might help pinpointing the issue.

[melvsparks]

The "New Enrollment" radio button was set using adobe and when I use pypdf to programmatically view the field data of both the generated form and the template form they have the same data. Maybe I'm filtering out important values that I don't know about.

It also looks like the updates that are happening for the DV values aren't being honored.

here's the output from the script to get the field values:

1. Policy number update
   Template

  "Policy Number": {
    "type": "/Tx",
    "has_value": false,
    "has_default_value": false,
    "value": null,
    "default_value": null,
    "raw_V": "MISSING",
    "raw_DV": "MISSING"
  }

Output pdf

  "Policy Number": {
    "type": "/Tx",
    "has_value": true,              // Updated
    "has_default_value": false,
    "value": "ABC123456",      // Updated
    "default_value": null,
    "raw_V": "ABC123456",      // Updated
    "raw_DV": "MISSING"
  }

2. Retain New enrollment radio button that's set in Adobe
   Template

  "Radio Button 3": {
    "type": "/Btn",
    "has_value": true,
    "has_default_value": false,
    "value": "/0",
    "default_value": null,
    "raw_V": "/0",
    "raw_DV": "MISSING",
    "kids": [
      {
        "index": 0,
        "appearance_state": "/0",
        "raw_AS": "/0",
        "has_V": false,
        "has_DV": false,
        "available_states": [
          "/0",
          "/Off"
        ]
      },
      {
        "index": 1,
        "appearance_state": "/Off",
        "raw_AS": "/Off",
        "has_V": false,
        "has_DV": false,
        "available_states": [
          "/1",
          "/Off"
        ]
      }
    ]
  }

Output pdf

  // No Changes
  "Radio Button 3": {
    "type": "/Btn",
    "has_value": true,
    "has_default_value": false,
    "value": "/0",
    "default_value": null,
    "raw_V": "/0",
    "raw_DV": "MISSING",
    "kids": [
      {
        "index": 0,
        "appearance_state": "/0",
        "raw_AS": "/0",
        "has_V": false,
        "has_DV": false,
        "available_states": [
          "/0",
          "/Off"
        ]
      },
      {
        "index": 1,
        "appearance_state": "/Off",
        "raw_AS": "/Off",
        "has_V": false,
        "has_DV": false,
        "available_states": [
          "/1",
          "/Off"
        ]
      }
    ]
  }

1. Update the Gender radio to female
   Template

  "Gender 01": {
    "type": "/Btn",
    "has_value": false,
    "has_default_value": false,
    "value": null,
    "default_value": null,
    "raw_V": "MISSING",
    "raw_DV": "MISSING",
    "kids": [
      {
        "index": 0,
        "appearance_state": "/Off",
        "raw_AS": "/Off",
        "has_V": false,
        "has_DV": false,
        "available_states": [
          "/0",
          "/Off"
        ]
      },
      {
        "index": 1,
        "appearance_state": "/Off",
        "raw_AS": "/Off",
        "has_V": false,
        "has_DV": false,
        "available_states": [
          "/1",
          "/Off"
        ]
      }
    ]
  }

Output pdf

  "Gender 01": {
    "type": "/Btn",
    "has_value": true, // Updated
    "has_default_value": false,
    "value": "/0", // Updated
    "default_value": null,
    "raw_V": "/0", // Updated
    "raw_DV": "MISSING",
    "kids": [
      {
        "index": 0,
        "appearance_state": "/0", // Updated
        "raw_AS": "/0", // Updated
        "has_V": true, // Updated
        "has_DV": false,
        "available_states": [
          "/0",
          "/Off"
        ]
      },
      {
        "index": 1,
        "appearance_state": "/Off",
        "raw_AS": "/Off",
        "has_V": true, // Updated
        "has_DV": false,
        "available_states": [
          "/1",
          "/Off"
        ]
      }
    ]
  }

[melvsparks]

It looks like the issue is actually deeper into the radio button components. When you print all the properties on each field, it looks like the underlying structure is being modified in a way that Adobe must not be liking. If you do a diff you can see the differences in the overall structure.

Here's an example
Template- (element on Radio Button 3) the first kid element's properties within the "kids" array

        "all_kid_properties": {
          "/AP": "{'/N': IndirectObject(261, 0, 1463065678928)}",
          "/AS": "/0",
          "/BS": "{'/S': '/I', '/W': 0}",
          "/F": "4",
          "/MK": "{'/BC': [0.0, 0.0, 0.0], '/BG': []}",
          "/P": "{'/Annots': [IndirectObject(244, 0, 1463065678928), IndirectObject(247, 0, 1463065678928), IndirectObject(259, 0, 1463065678928), IndirectObject(273, 0, 1463065678928), IndirectObject(287, 0, 1463065678928), IndirectObject(295, 0, 1463065678928), IndirectObject(309, 0, 1463065678928), IndirectObject(323, 0, 1463065678928), IndirectObject(337, 0, 1463065678928), IndirectObject(350, 0, 1463065678928), IndirectObject(363, 0, 1463065678928), IndirectObject(376, 0, 1463065678928), IndirectObject(389, 0, 1463065678928), IndirectObject(402, 0, 1463065678928), IndirectObject(416, 0, 1463065678928), IndirectObject(424, 0, 1463065678928), IndirectObject(432, 0, 1463065678928), IndirectObject(473, 0, 1463065678928), IndirectObject(446, 0, 1463065678928), IndirectObject(481, 0, 1463065678928), IndirectObject(459, 0, 1463065678928), IndirectObject(489, 0, 1463065678928), IndirectObject(497, 0, 1463065678928), IndirectObject(505, 0, 1463065678928), IndirectObject(513, 0, 1463065678928), IndirectObject(521, 0, 1463065678928), IndirectObject(529, 0, 1463065678928), IndirectObject(542, 0, 1463065678928), IndirectObject(550, 0, 1463065678928), IndirectObject(564, 0, 1463065678928), IndirectObject(578, 0, 1463065678928), IndirectObject(586, 0, 1463065678928), IndirectObject(594, 0, 1463065678928), IndirectObject(602, 0, 1463065678928), IndirectObject(610, 0, 1463065678928), IndirectObject(618, 0, 1463065678928), IndirectObject(626, 0, 1463065678928), IndirectObject(634, 0, 1463065678928), IndirectObject(642, 0, 1463065678928), IndirectObject(650, 0, 1463065678928)], '/ArtBox': [0.0, 0.0, 612, 792], '/BleedBox': [0.0, 0.0, 612, 792], '/Contents': [IndirectObject(5, 0, 1463065678928), IndirectObject(6, 0, 1463065678928), IndirectObject(7, 0, 1463065678928), IndirectObject(8, 0, 1463065678928), IndirectObject(9, 0, 1463065678928), IndirectObject(10, 0, 1463065678928), IndirectObject(11, 0, 1463065678928), IndirectObject(12, 0, 1463065678928)], '/CropBox': [0.0, 0.0, 612, 792], '/LastModified': \"D:20250728161114-05'00'\", '/MediaBox': [0.0, 0.0, 612, 792], '/Parent': IndirectObject(2, 0, 1463065678928), '/PieceInfo': IndirectObject(13, 0, 1463065678928), '/Resources': IndirectObject(19, 0, 1463065678928), '/Rotate': 0, '/Tabs': '/W', '/Thumb': IndirectObject(82, 0, 1463065678928), '/TrimBox': [0.0, 0.0, 612, 792], '/Type': '/Page'}",
          "/Parent": "{'/FT': '/Btn', '/Ff': 49152, '/Kids': [IndirectObject(259, 0, 1463065678928), IndirectObject(273, 0, 1463065678928)], '/Opt': IndirectObject(286, 0, 1463065678928), '/T': 'Radio Button 3', '/TU': 'Reason for Enrollment', '/V': '/0'}",
          "/Rect": "[118.297, 606.993, 129.222, 617.918]",
          "/Subtype": "/Widget",
          "/Type": "/Annot"
        }

Output pdf

        "all_kid_properties": {
          "/AP": "{'/N': IndirectObject(103, 0, 1463065223792)}",
          "/AS": "/0",
          "/BS": "{'/S': '/I', '/W': 0}",
          "/F": "4",
          "/MK": "{'/BC': [0.0, 0.0, 0.0], '/BG': []}",
          "/P": "{'/ArtBox': [0.0, 0.0, 612, 792], '/BleedBox': [0.0, 0.0, 612, 792], '/Contents': [IndirectObject(5, 0, 1463065223792), IndirectObject(6, 0, 1463065223792), IndirectObject(7, 0, 1463065223792), IndirectObject(8, 0, 1463065223792), IndirectObject(9, 0, 1463065223792), IndirectObject(10, 0, 1463065223792), IndirectObject(11, 0, 1463065223792), IndirectObject(12, 0, 1463065223792)], '/CropBox': [0.0, 0.0, 612, 792], '/LastModified': \"D:20250728161114-05'00'\", '/MediaBox': [0.0, 0.0, 612, 792], '/PieceInfo': IndirectObject(13, 0, 1463065223792), '/Resources': IndirectObject(19, 0, 1463065223792), '/Rotate': 0, '/Tabs': '/W', '/Thumb': IndirectObject(82, 0, 1463065223792), '/TrimBox': [0.0, 0.0, 612, 792], '/Type': '/Page', '/Parent': IndirectObject(2, 0, 1463065223792), '/Annots': [IndirectObject(86, 0, 1463065223792), IndirectObject(89, 0, 1463065223792), IndirectObject(101, 0, 1463065223792), IndirectObject(115, 0, 1463065223792), IndirectObject(129, 0, 1463065223792), IndirectObject(137, 0, 1463065223792), IndirectObject(151, 0, 1463065223792), IndirectObject(165, 0, 1463065223792), IndirectObject(179, 0, 1463065223792), IndirectObject(192, 0, 1463065223792), IndirectObject(205, 0, 1463065223792), IndirectObject(218, 0, 1463065223792), IndirectObject(231, 0, 1463065223792), IndirectObject(244, 0, 1463065223792), IndirectObject(258, 0, 1463065223792), IndirectObject(266, 0, 1463065223792), IndirectObject(274, 0, 1463065223792), IndirectObject(315, 0, 1463065223792), IndirectObject(288, 0, 1463065223792), IndirectObject(323, 0, 1463065223792), IndirectObject(301, 0, 1463065223792), IndirectObject(331, 0, 1463065223792), IndirectObject(339, 0, 1463065223792), IndirectObject(347, 0, 1463065223792), IndirectObject(355, 0, 1463065223792), IndirectObject(363, 0, 1463065223792), IndirectObject(371, 0, 1463065223792), IndirectObject(384, 0, 1463065223792), IndirectObject(392, 0, 1463065223792), IndirectObject(406, 0, 1463065223792), IndirectObject(420, 0, 1463065223792), IndirectObject(428, 0, 1463065223792), IndirectObject(436, 0, 1463065223792), IndirectObject(444, 0, 1463065223792), IndirectObject(452, 0, 1463065223792), IndirectObject(460, 0, 1463065223792), IndirectObject(468, 0, 1463065223792), IndirectObject(476, 0, 1463065223792), IndirectObject(484, 0, 1463065223792), IndirectObject(492, 0, 1463065223792)]}",
          "/Parent": "{'/FT': '/Btn', '/Ff': 49152, '/Kids': [IndirectObject(101, 0, 1463065223792), IndirectObject(115, 0, 1463065223792)], '/Opt': IndirectObject(128, 0, 1463065223792), '/T': 'Radio Button 3', '/TU': 'Reason for Enrollment', '/V': '/0'}",
          "/Rect": "[118.297, 606.993, 129.222, 617.918]",
          "/Subtype": "/Widget",
          "/Type": "/Annot"
        }

[stefan6419846]

It looks like the issue is actually deeper into the radio button components. When you print all the properties on each field, it looks like the underlying structure is being modified in a way that Adobe must not be liking.

Please provide the diff you are referring to. At first sight, /P might look different, but this mostly affects the sorting if I am not mistaken.

[melvsparks]

I switched to a different branch, so I dont have the diff changes at this current moment. I can send tomorrow, but all I did was put the two files into chatgpt and ask it to use pypdf to get the full decoded details of each pdf and output them as JSON. Once I had the files, I asked it to take a diff.

Regardless of the diff, if you think those /Ps that are different aren't the culprit, then it must be something else. The last objects I sent were the only properties (kid values) on Radio button 3 that have changed. I'm not sure what could be causing this issue.

[stefan6419846]

I just tried to reproduce this issue, although not on Adobe Acrobat. The first and most important part: I could not reproduce this issue when omitting the Radio Button 3 field completely during the update. This is what I would have expected.

When trying around, I still discovered some oddities:

• Setting /1 does not work due to the parent annotation receiving a string instead of a name object:

  pypdf/pypdf/_writer.py

  Line 1016 in 97d47a0

  parent_annotation[NameObject(FA.V)] = TextStringObject(value)

  It seems like we need to replace

  pypdf/pypdf/_writer.py

  Line 1030 in 97d47a0

  annotation[NameObject(FA.V)] = v

  with parent_annotation[NameObject(FA.V)] = v. BUG: Fix check box value which should be name object #3124 has used the wrong reference when looking into Form rendering differences for textboxes and checkboxes when generated with pypdf and Acrobat #3115 (comment).
• Setting /0 still does not work after this fix, as we are looking at the annotation widgets and the widget for New (17) has a smaller object number than the one for Add Dependant (52), while

  pypdf/pypdf/_writer.py

  Lines 1025 to 1026 in 97d47a0

  	if v not in normal_ap:
  	v = NameObject("/Off")

  expects the widget's appearance stream to contain the target value. For this reason, we set the correct value /0 when seeing object 17, but object 52 resets this to /Off due to object 52 not containing the value /1, but only /0 and /Off (object 54; for object 17, this is object 19). This requires a more complex approach for fixing, where I am open to proposals on how to solve this.

[stefan6419846]

It seems like "just" fixing the first part without looking into the second part is not possible due to exposing the object order issue from the second part:

___________________________ test_update_form_fields ____________________________
[gw1] linux -- Python 3.14.2 /opt/hostedtoolcache/Python/3.14.2/x64/bin/python

tmp_path = PosixPath('/tmp/pytest-of-runner/pytest-0/popen-gw1/test_update_form_fields0')

    def test_update_form_fields(tmp_path):
        write_data_here = tmp_path / "out.pdf"
        writer = PdfWriter(clone_from=RESOURCE_ROOT / "FormTestFromOo.pdf")
        writer.update_page_form_field_values(
            writer.pages[0],
            {
                "CheckBox1": "/Yes",
                "Text1": "mon Text1",
                "Text2": "ligne1\nligne2",
                "RadioGroup1": "/2",
                "RdoS1": "/",
                "Combo1": "!!monCombo!!",
                "Liste1": "Liste2",
                "Liste2": ["Lst1", "Lst3"],
                "DropList1": "DropListe3",
            },
            auto_regenerate=False,
            flatten=True,
        )
        del writer.pages[0]["/Annots"][1].get_object()["/AP"]["/N"]
        del writer.pages[0]["/Resources"]["/Font"]
        writer.update_page_form_field_values(
            writer.pages[0],
            {"Text1": "my Text1", "Text2": "ligne1\nligne2\nligne3"},
            auto_regenerate=False,
        )
        writer.update_page_form_field_values(
            writer.pages[0],
            {"Text1": None, "Text2": None},
            auto_regenerate=False,
            flatten=True,
        )
    
        writer.write(write_data_here)
        reader = PdfReader(write_data_here)
        flds = reader.get_fields()
        assert flds["CheckBox1"]["/V"] == "/Yes"
        assert flds["CheckBox1"].indirect_reference.get_object()["/AS"] == "/Yes"
        assert (
            b"(my Text1)"
            in flds["Text1"].indirect_reference.get_object()["/AP"]["/N"].get_data()
        )
        assert flds["Text2"]["/V"] == "ligne1\nligne2\nligne3"
        assert (
            b"(ligne3)"
            in flds["Text2"].indirect_reference.get_object()["/AP"]["/N"].get_data()
        )
>       assert flds["RadioGroup1"]["/V"] == "/2"
E       AssertionError: assert '/Off' == '/2'
E         
E         - /2
E         + /Off

tests/test_writer.py:1560: AssertionError
------------------------------ Captured log call -------------------------------
WARNING  pypdf._writer:_utils.py:457 XObject '/Fm_RadioGroup1' already added to page resources. This might be an issue.
WARNING  pypdf._writer:_utils.py:457 XObject '/Fm_RadioGroup1' already added to page resources. This might be an issue.
WARNING  pypdf._writer:_utils.py:457 XObject '/Fm_Text1' already added to page resources. This might be an issue.
WARNING  pypdf._writer:_utils.py:457 XObject '/Fm_Text2' already added to page resources. This might be an issue.

The warnings already seem to indicate the problematic overwriting behavior, although it seems like it remained unaddressed until now.

If someone wants to further look into this and extend on my previous approaches, please outline possible solutions in a comment for discussion before opening a PR.