Sablon 0.4.3 generates .docx files that Google Drive cannot process

[ebabian]

Description
Word docx files generated by Sablon 0.4.3 don't preview or open in Google Docs, while 0.4.2 works fine.

After upgrading from Sablon 0.4.2 to 0.4.3 (along with rubyzip from 2.4.1 to 3.2.2), all generated .docx files fail to preview or open in Google Docs when uploaded via the Google Drive API. The files open correctly in Microsoft Word, indicating they are valid .docx files, but Google Drive's processing fails.

Environment
Ruby: 3.3.6
Sablon 0.4.3 with rubyzip 3.2.2 (broken)
Sablon 0.4.2 with rubyzip 2.4.1 (working)
Microsoft Word: Version 16.103.1
macOS

Steps to Reproduce:

1. Generate a .docx file using Sablon 0.4.3:

template = Sablon.template(File.expand_path("path/to/template.docx"))
tempfile = Tempfile.new(["output", ".docx"], Rails.root.join("tmp"))
template.render_to_file(tempfile, context)

2. Upload the generated file to Google Drive via API:

google_client.drive_service.create_file(
  Google::Apis::DriveV3::File.new(name: "Test Document", parents: [folder_id]),
  upload_source: tempfile.path,
  content_type: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
)

3. Attempt to preview or open the file in Google Docs

Expected Behavior: Files should preview and open in Google Docs, as they did with Sablon 0.4.2

Actual Behavior:

• Files show "Couldn't preview file" error in Google Drive
• "Open with Google Docs" button fails to open the document
• Google Drive metadata shows hasThumbnail: false
• Files download and open correctly in Microsoft Word

Timeline:

• Before November 24, 2025: All documents working (Sablon 0.4.2)
• November 24, 2025: Upgraded to Sablon 0.4.3 via dependency update
• Late November 2025: Users reported documents no longer opening in Google Docs
• December 16, 2025: Identified root cause through systematic testing
• December 17, 2025: Confirmed downgrade to 0.4.2 fixes the issue

Workaround: Downgrade to Sablon 0.4.2 and rubyzip 2.4.1

gem 'sablon', '0.4.2'
gem 'rubyzip', '2.4.1'

[senny]

Hi @ebabian

Thanks for the detailed writeup. Please note that this library is currently unmaintained. Due to community request, I have merged and published #204 but am not able to solve problems caused by said change.

Maybe @bliof is inclined to investigate the issue. Otherwise, I only see the option to revoke the release.

[bliof]

👍 I was able to replicate it. Happy to take a look.

[bliof]

I've generated a quick script to compare the contents of the generated files using

• sablon v0.4.3 with rubyzip 2.3.2
• sablon v0.4.3 with rubyzip 3.2.2

And the unzipped folders are the same. There is a difference in the file headers.

If you set this with rubyzip v3, the files will open in google drive:

Zip.write_zip64_support = false

There is a way to codify it by using https://github.com/rubyzip/rubyzip/tree/v3.2.0?tab=readme-ov-file#suppressing-extra-fields but that's a new option so rubyzip 3.0 / 3.1 don't have it.

Related rubyzip/rubyzip#648 so both docx and xlsx have issues with zip64 in google drive.

[senny]

@bliof thank you for the quick solution. @ebabian can you run the associated PR and see if that resolves your problem?