Welcome to the first monthly report in 2026 from the Reproducible Builds project! These reports outline what we ve been up to over the past month, highlighting items of news from elsewhere in the increasingly-important area of software supply-chain security. As ever, if you are interested in contributing to the Reproducible Builds project, please see the Contribute page on our website.

1. Flathub now testing for reproducibility
2. Reproducibility identifying projects that will fail to build in 2038
3. Distribution work
4. Tool development
5. Two new academic papers
6. Upstream patches

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Flathub now testing for reproducibility Flathub, the primary repository/app store for Flatpak-based applications, has begun checking for build reproducibility. According to a recent blog post:

We have started testing binary reproducibility of x86_64 builds targeting the stable repository. This is possible thanks to flathub-repro-checker, a tool doing the necessary legwork to recreate the build environment and compare the result of the rebuild with what is published on Flathub. While these tests have been running for a while now, we have recently restarted them from scratch after enabling S3 storage for diffoscope artifacts.

The test results and status is available on their reproducible builds page.

Reproducibility identifying software projects that will fail to build in 2038 Longtime Reproducible Builds developer Bernhard M. Wiedemann posted on Reddit on Y2K38 commemoration day T-12 that is to say, twelve years to the day before the UNIX Epoch will no longer fit into a signed 32-bit integer variable on 19th January 2038. Bernhard s comment succinctly outlines the problem as well as notes some of the potential remedies, as well as links to a discussion with the GCC developers regarding adding warnings for int time_t conversions . At the time of publication, Bernhard s topic had generated 50 comments in response.

Distribution work Conda is language-agnostic package manager which was originally developed to help Python data scientists and is now a popular package manager for Python and R. conda-forge, a community-led infrastructure for Conda recently revamped their dashboards to rebuild packages straight to track reproducibility. There have been changes over the past two years to make the conda-forge build tooling fully reproducible by embedding the lockfile of the entire build environment inside the packages.
In Debian this month:

• Scott Talbert uploaded a new version of dh-haskell (0.6.13), reverting parallel support as it broke reproducibility, thereby fixing Debian bug #1125000.
• Vagrant Cascadian posted to our mailing list on the topic of Duplicate Debian packages with matching name-version-arch problem . The issue is that .buildinfo files only record the package name, version and architecture of the build-dependencies (and perhaps a bit more), but there are corner cases where multiple artifacts have the same name, version and architecture . This generated some discussion on the mailing list as well as elsewhere in Debian.
• Roland Clobus also posted to our mailing list regarding Building Debian Live images from snapshot.debian.org. This surfaced an issue regarding the timestamps of the .deb file, leading to Roland filing Debian bug #1126000 to liaise with the developers of the snapshot.debian.org service.
• A change was made to migrate away from using the results from tests.reproducible-builds.org in deciding whether a package is a suitable candidate for the Debian testing distribution (the staging area for the next stable Debian release) to use the results from reproduce.debian.net instead. This was, according to Paul Gevers merge request, because the former service does so by building twice in a row with varying build environment. What we are actually interested in is if the binaries that we ship can be reproduced . The information provided by reproduce.debian.net in future will be used to delay or speed up packages migration time based on their reproducibility status, and further in the future shall be used to block unreproducible packages from migrating entirely.
• 41 reviews of Debian packages were added, 7 were updated and 37 were removed this month adding to our knowledge about identified issues. Chris Lamb identified and added a new source_date_epoch_affected_by_timezone_by_d_compiler_gdc issue type, as well as timezone_variant_in_argparse_manpage.

In NixOS this month, it was announced that the GNU Guix Full Source Bootstrap was ported to NixOS as part of Wire Jansen bachelor s thesis (PDF). At the time of publication, this change has landed in NiX stdev distribution.
Lastly, Bernhard M. Wiedemann posted another openSUSE monthly update for his work there.

Tool development diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made the following changes, including preparing and uploading versions, 310 and 311 to Debian.

• Fix test compatibility with u-boot-tools version 2026-01. [ ]
• Drop the implied Rules-Requires-Root: no entry in debian/control. [ ]
• Bump Standards-Version to 4.7.3. [ ]
• Reference the Debian ocaml package instead of ocaml-nox. (#1125094)
• Apply a patch by Jelle van der Waa to adjust a test fixture match new lines. [ ]
• Also the drop implied Priority: optional from debian/control. [ ]

In addition, Holger Levsen uploaded two versions of disorderfs, first updating the package from FUSE 2 to FUSE 3 as described in last months report, as well as updating the packaging to the latest Debian standards. A second upload (0.6.2-1) was subsequently made, with Holger adding instructions on how to add the upstream release to our release archive and incorporating changes by Roland Clobus to set _FILE_OFFSET_BITS on 32-bit platforms, fixing a build failure on 32-bit systems. Vagrant Cascadian updated diffoscope in GNU Guix to version 311-2-ge4ec97f7 and disorderfs to 0.6.2.

Two new academic papers Julien Malka, Stefano Zacchiroli and Th o Zimmermann of T l com Paris in-house research laboratory, the Information Processing and Communications Laboratory (LTCI) published a paper this month titled Docker Does Not Guarantee Reproducibility:

[ ] While Docker is frequently cited in the literature as a tool that enables reproducibility in theory, the extent of its guarantees and limitations in practice remains under-explored. In this work, we address this gap through two complementary approaches. First, we conduct a systematic literature review to examine how Docker is framed in scientific discourse on reproducibility and to identify documented best practices for writing Dockerfiles enabling reproducible image building. Then, we perform a large-scale empirical study of 5,298 Docker builds collected from GitHub workflows. By rebuilding these images and comparing the results with their historical counterparts, we assess the real reproducibility of Docker images and evaluate the effectiveness of the best practices identified in the literature.

A PDF of their paper is available online.
Quentin Guilloteau, Antoine Waehren and Florina M. Ciorba of the University of Basel in Sweden also published a Docker-related paper, theirs called Longitudinal Study of the Software Environments Produced by Dockerfiles from Research Artifacts:

The reproducibility crisis has affected all scientific disciplines, including computer science (CS). To address this issue, the CS community has established artifact evaluation processes at conferences and in journals to evaluate the reproducibility of the results shared in publications. Authors are therefore required to share their artifacts with reviewers, including code, data, and the software environment necessary to reproduce the results. One method for sharing the software environment proposed by conferences and journals is to utilize container technologies such as Docker and Apptainer. However, these tools rely on non-reproducible tools, resulting in non-reproducible containers. In this paper, we present a tool and methodology to evaluate variations over time in software environments of container images derived from research artifacts. We also present initial results on a small set of Dockerfiles from the Euro-Par 2024 conference.

A PDF of their paper is available online.

Miscellaneous news On our mailing list this month:

• kpcyrd started a thread after they noticed that SWHID (also known as ISO/IEC 18670:2025) was published 1.0 in 2022 and ISO standardized in 2025, but uses the insecure SHA-1 as core cryptographic primitive , asking whether there have been any attempts to upgrade this to SHA-256 or similar.
• Jan-Benedict Glaw asked about the Reproducibility for Libreoffice [when performing] ODT to PDF conversion after they observed that simply calling libreoffice --convert-to pdf some.odt results in unreproducible output PDF. After some replies, Jan-Benedict wrote back to observe that it may be an issue with both timestamps and embedded fonts.

Lastly, kpcyrd added a Rust section to the Stable order for outputs page on our website. [ ]

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

• Bernhard M. Wiedemann:
  • clamav
  • kf6-kuserfeedback
  • libaom
  • Nim
  • otp
  • Switcheroo (by Khaleel Al-Adhami)
  • uwsm
  • ZEO
• Chris Lamb:
  • #1124697 filed against sqlalchemy-i18n.
  • #1125671 filed against tea-cli.
  • #1125725 filed against libimage-librsvg-perl.
  • #1125727 filed against seer.
  • #1125729 filed against grabix.
  • #1126038 filed against hovercraft.
  • #1126039 filed against lomiri-location-service.
  • #1126092 filed against argparse-manpage.
  • #1126454 filed against xarray-safe-rcm.
  • #1126512 filed against gcc-15 (forwarded upstream).
• Jochen Sprickerhof:
  • #1124951 filed against rsyslog.
  • #1125000 filed against dh-haskell.

Finally, if you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

• IRC: #reproducible-builds on irc.oftc.net.
• Mastodon: @reproducible_builds@fosstodon.org
• Mailing list: rb-general@lists.reproducible-builds.org

Debian Contributions: 2025-08 Contributing to Debian is part of Freexian s mission. This article covers the latest achievements of Freexian and their collaborators. All of this is made possible by organizations subscribing to our Long Term Support contracts and consulting services.

Preparing for setup.py install deprecation, by Colin Watson setuptools upstream will be removing the setup.py install command on 31 October. While this may not trickle down immediately into Debian, it does mean that in the near future nearly all Python packages will have to use pybuild-plugin-pyproject (though they don t necessarily have to use pyproject.toml; this is just a question of how the packaging runs the build system). Some of the Python team talked about this a bit at DebConf, and Colin volunteered to write up some notes on cases where this isn t straightforward. This page will likely grow as the team works on this problem.

Salsa CI, by Santiago Ruano Rinc n Santiago fixed some pending issues in the MR that moves the pipeline to sbuild+unshare, and after several months, Santiago was able to mark the MR as ready. Part of the recent fixes include handling external repositories, honoring the RELEASE autodetection from d/changelog (thanks to Ahmed Siam for spotting the main reason of the issue), and fixing a regression about the apt resolver for *-backports releases. Santiago is currently waiting for a final review and approval from other members of the Salsa CI team, and being able to merge it. Thanks to all the folks who have helped testing the changes or provided feedback so far. If you want to test the current MR, you need to include the following pipeline definition in your project s CI config file:

---
include:
  - https://salsa.debian.org/santiago/pipeline/raw/sbuild-unshare-02-salsa-ci/salsa-ci.yml
  - https://salsa.debian.org/santiago/pipeline/raw/sbuild-unshare-02-salsa-ci/pipeline-jobs.yml

As a reminder, this MR will make the Salsa CI pipeline build the packages more similar to how it s built by the Debian official builders. This will also save some resources, since the default pipeline will have one stage less (the provisioning) stage, and will make it possible for more projects to be built on salsa.debian.org (including large projects and those from the OCaml ecosystem), etc. See the different issues being fixed in the MR description.

Debian 13 trixie release, by Emilio Pozuelo Monfort On August 9th, Debian 13 trixie was released, building on two years worth of updates and bug fixes from hundreds of developers. Emilio helped coordinate the release, communicating with several teams involved in the process.

DebConf 26 Site Visit, by Stefano Rivera Stefano visited Santa Fe, Argentina, the site for DebConf 26 next year. The aim of the visit was to help build a local team and see the conference venue first-hand. Stefano and Nattie represented the DebConf Committee. The local team organized Debian meetups in Buenos Aires and Santa Fe, where Stefano presented a talk on Debian and DebConf. Venues were scouted and the team met with the university management and local authorities.

Miscellaneous contributions

• Rapha l updated tracker.debian.org after the trixie release to add the new forky release in the set of monitored distributions. He also reviewed and deployed the work of Scott Talbert showing open merge requests from salsa in the action needed panel.
• Rapha l reviewed some DEP-3 changes to modernize the embedded examples in light of the broad git adoption.
• Rapha l configured new workflows on debusine.debian.net to upload to trixie and trixie-security, and officially announced the service on debian-devel-announce, inviting Debian developers to try the service for their next upload to unstable.
• Carles created a merge request for django-compressor upstream to fix an error when concurrent node processing happened. This will allow removing a workaround added in openstack-dashboard and avoid the same bug in other projects that use django-compressor.
• Carles prepared a system to detect packages that Recommends packages which don t exist in unstable. Processed (either reported or ignored due to mis-detected problems or temporary problems) 16% of the reports. Will continue next month.
• Carles got familiar and gave feedback for the freedict-wikdict package. Planned contributions with the maintainer to improve the package.
• Helmut responded to queries related to /usr-move.
• Helmut adapted crossqa.d.n to the release of trixie .
• Helmut diagnosed sufficient failures in rebootstrap to make it work with gcc-15.
• Helmut fixed the CI pipeline of debvm.
• Helmut sent patches for 19 cross build problems.
• Faidon discovered that the Multi-Arch hinter would emit confusing hints about :any annotations. Helmut identified the root cause to be the handling of virtual packages and fixed it.
• Enrico took some dust off python-debiancontributors and prototyped a receiving end for salsa webpings, to start followup work to contributors.debian.org discussions at DebConf25.
• Colin upgraded about 70 Python packages to new upstream versions, which is around 10% of the backlog; this included a complicated Pydantic upgrade in collaboration with the Rust team.
• Colin fixed a bug in debbugs that caused incoming emails to bugs.debian.org with certain header contents to go missing.
• Thorsten uploaded sane-airscan, which was already in experimental, to unstable.
• Thorsten created a script to automate the upload of new upstream versions of foomatic-db. The database contains information about printers and regularly gets an update. Now it is possible to keep the package more up to date in Debian.
• Stefano prepared updates to almost all of his packages that had new versions waiting to upload to unstable. (beautifulsoup4, hatch-vcs, mkdocs-macros-plugin, pypy3, python-authlib, python-cffi, python-mitogen, python-pip, python-pipx, python-progress, python-truststore, python-virtualenv, re2, snowball, soupsieve).
• Stefano uploaded two new python3.13 point releases to unstable.
• Stefano updated distro-info-data in stable releases, to document the trixie release and expected EoL dates.
• Stefano did some debian.social sysadmin work (keeping up quotas with growing databases and filesystems).
• Stefano supported the Debian treasurers in processing some of the DebConf 25 reimbursements.
• Lucas uploaded ruby3.4 to experimental. It was already approved by FTP masters.
• Lucas uploaded ruby-defaults to experimental to add support for ruby3.4. It will allow us to start triggering test rebuilds and catch any FTBFS with ruby3.4.
• Lucas did some administrative work for Google Summer of Code (GSoC) and replied to some queries from mentors and students.
• Anupa helped to organize release parties for Debian 13 and Debian Day events.
• Anupa did the live coverage for the Debian 13 release and prepared the Bits post for the release announcement and 32nd Debian Day as part of the Debian Publicity team.
• Anupa attended a Debian Day event organized by FOSS club SSET as a speaker.

The diffoscope maintainers are pleased to announce the release of diffoscope version 220. This version includes the following changes: You find out more by visiting the project homepage.

Welcome to gambaru.de. Here is my monthly report (+ the first week in May) that covers what I have been doing for Debian. If you re interested in Java, Games and LTS topics, this might be interesting for you. Debian Games

• Scott Talbert did a fantastic job by porting playonlinux, a user-friendly frontend for Wine, to Python 3 (#937302). I tested his patch and uploaded the package today. More testing and feedback is welcome. Scott s work basically prevented the removal of one of the most popular packages in the games section. I believe this will also give interested people more time to package the Java successor of playonlinux called Phoenicis.
• Reiner Herrmann ported ardentryst, an action role playing game, to Python 3 to fix a release critical Py2 removal bug (#936148). He also packaged the latest release of xaos, a real-time interactive fractal zoomer, and improved various packaging details. I reviewed both of them and sponsored the upload for him.
• I packaged new upstream releases of minetest, lordsawar, gtkatlantic and cutemaze.
• I also sponsored a new simutrans update for J rg Frings-F rst.

Debian Java

• New upstream versions this month: jboss-modules, robocode, sweethome3d, sweethome3d-furniture-editor, jboss-logmanager, jboss-threads and undertow.
• I prepared the security updates for tomcat9 (DSA-4680-1) and apache-log4j1.2.

Misc

• I packaged new versions of wabt and binaryen, required to build Webassembly code from source.

Debian LTS This was my 50. month as a paid contributor and I have been paid to work 11,5 hours on Debian LTS, a project started by Rapha l Hertzog. In that time I did the following:

• I completed the security update of Tomcat 8 in Stretch released as DSA-4673-1 and Tomcat 8 in Jessie soon to be released as DLA-2209-1.
• I am currently assigned more hours and my plan is to invest the time in a project to improve our knowledge about embedded code copies and their current security impact which I want to discuss with the security team. The rest will be spent on Stretch security updates which will become the new LTS release soon.

ELTS Extended Long Term Support (ELTS) is a project led by Freexian to further extend the lifetime of Debian releases. It is not an official Debian project but all Debian users benefit from it without cost. The current ELTS release is Debian 7 Wheezy . This was my 23. month and I have been paid to work 2 hours on ELTS.

• I prepared the fix for CVE-2019-18218 in php5 released as ELA-227-1.
• I checked jetty for unfixed vulnerabilities and discovered that the version in Wheezy was not affected by CVE-2019-17632. No further action was required.
• It turned out that the apache2 package in Wheezy was not affected by vulnerable embedded expat code because it depends on already fixed system packages.

Thanks for reading and see you next time.

The following contributors got their Debian Developer accounts in the last two months:

• Gard Spreemann (gspr)
• Jonathan Bustillos (jathan)
• Scott Talbert (swt2c)

The following contributors were added as Debian Maintainers in the last two months:

• Thiago Andrade Marques
• William Grzybowski
• Sudip Mukherjee
• Birger Schacht
• Michael Robin Crusoe
• Lars Tangvald
• Alberto Molina Coballes
• Emmanuel Arias
• Hsieh-Tseng Shen
• Jamie Strandboge

Congratulations!

The following contributors got their Debian Developer accounts in the last two months:

• Stein Magnus Jodal (jodal)
• Prach Pongpanich (prach)
• Markus Koschany (apo)
• Bernhard Schmidt (berni)
• Uwe Kleine-K nig (ukleinek)
• Timo Weing rtner (tiwe)
• Sebastian Andrzej Siewior (bigeasy)
• Mattia Rizzolo (mattia)
• Alexandre Viau (aviau)
• Lev Lamberov (dogsleg)
• Adam Borowski (kilobyte)
• Chris Boot (bootc)

The following contributors were added as Debian Maintainers in the last two months:

• Alf Gaida
• Andrew Ayer
• Marcio de Souza Oliveira
• Alexandre Detiste
• Dave Hibberd
• Andreas Boll
• Punit Agrawal
• Edward Betts
• Shih-Yuan Lee
• Ivan Udovichenko
• Andrew Kelley
• Benda Xu
• Russell Sim
• Paulo Roberto Alves de Oliveira
• Marc Fournier
• Scott Talbert
• Sergio Durigan Junior
• Guillaume Turri
• Michael Lustfield

Congratulations!