md5sum: breaking Anaconda/Miniconda installation on Ubuntu 25.10

Description

The md5sum utility in uutils/coreutils version 0.2.2 produces different checksums than GNU coreutils' md5sum for the same input, causing installation failures for Anaconda and Miniconda on Ubuntu 25.10.

Environment

• OS: Ubuntu 25.10 (Questing Quokka)
• Architecture: x86_64
• uutils coreutils version: 0.2.2-0ubuntu2 (from rust-coreutils package)
• GNU coreutils version (working): 9.5-1ubuntu4
• Package: rust-coreutils 0.2.2-0ubuntu2

Reproduction

1. Install Ubuntu 25.10 (which uses Rust-based coreutils by default)
2. Download Miniconda installer:

   wget https://repo.anaconda.com/miniconda/Miniconda3-py313_25.7.0-2-Linux-x86_64.sh
   

3. Verify external integrity (this passes):

   sha256sum Miniconda3-py313_25.7.0-2-Linux-x86_64.sh
   

4. Run installer:

   bash Miniconda3-py313_25.7.0-2-Linux-x86_64.sh
   

5. Observe failure during "Unpacking payload" with:

   WARNING: md5sum mismatch of tar archive
   BrokenProcessPool: A process in the process pool was terminated abruptly
   

The same installer file works correctly after switching to GNU coreutils:

sudo apt install coreutils-from-gnu coreutils-from-uutils- --allow-remove-essential
bash Miniconda3-py313_25.7.0-2-Linux-x86_64.sh  # Now succeeds

Version Comparison

uutils (problematic):

$ /usr/lib/cargo/bin/coreutils/md5sum --version
/usr/lib/cargo/bin/coreutils/md5sum (uutils coreutils) 0.2.2

GNU coreutils (working):

$ /usr/bin/gnumd5sum --version
md5sum (GNU coreutils) 9.5

Expected Behavior

md5sum should produce identical checksums to GNU coreutils' md5sum for the same input.

Actual Behavior

The installer's internal MD5 checksum verification fails because the calculated checksum doesn't match the expected value (which is correct for GNU coreutils).

Additional Context

• External file integrity check (SHA256) passes on multiple systems (Ubuntu 25.10 and 24.04 LTS)
• Issue occurs with both Anaconda 2025.06-0/1 and Miniconda py313_25.7.0-2
• The installers are self-extracting shell scripts that verify internal tar archive checksums during unpacking
• The issue is reproducible consistently on fresh Ubuntu 25.10 installations
• Original report: https://forum.anaconda.com/t/critical-installation-failure-persistent-internal-md5-mismatch-anaconda-miniconda-2025-06-on-ubuntu-25-10/107525

Impact

This is a critical compatibility issue. Ubuntu 25.10 users cannot install Anaconda/Miniconda (widely-used scientific computing platforms) without manually reverting to GNU coreutils, which undermines the goal of being a drop-in replacement.

Questions

1. Are there known differences in how uutils md5sum handles piped input or processes data from tar archives?
2. What diagnostic information would help narrow down the root cause?
3. Is there a way to extract a minimal test case from the installer to debug this further?

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Disclaimer: This report was created with the assistance of Google Gemini 3.5 Pro and GitHub Copilot with Claude Sonnet 4.5 for clarity, comprehensive detailing of technical steps, and proper formatting according to the project's contributing guidelines. This disclaimer is included at my request for transparency reasons. Also, this issue has been created from my machine after the workaround (reverting to older coreutils) had already been applied and Anaconda successfully installed.

Start with the md5sum entry point and reproduce the mismatch using the Miniconda installer and the provided Ubuntu 25.10 environment, comparing uutils output with GNU md5sum. Narrow the installer input to a minimal case if possible; done means uutils produces the same checksum and the installer completes successfully.