Getting help with dulwich build failure on unstable

Run into a problem trying to perform nixos-rebuild on the unstable channel, python 3.8 is required by nix-prefetch-scripts, system-path and nix-prefetch-scripts_fish-completions, but 6 unit tests fail in dulwich and the build fails. I’m still very new and I’m not really familiar with the ettiquite or the use of tooling to deal with issues like this, just want to ask some questions before I try to create an issue.

  1. How would I report this on github? Am I expected to see first if it works in master before reporting? How would I even switch to master? What counts as steps to reproduce here? Do I ping the maintainer of dulwich itself or the maintainers of the packages that depend on it? Do I try to make a minimal configuration.nix that causes the build to fail? Is there a way to point nixos-rebuild to an alternative file for the purpose of testing, and do a dry-run? It would be neat to pin this to a specific revision.

  2. Is there some workaround I can do in the meantime? Can I fix the python version to 3.7 instead, or check out a specific version of unstable that works? I can’t use 20.09 for the moment because I need nix-flakes enabled and that will not build on 20.09, but I do hope that I can switch to stable 21.05 when it’s out.

  3. What’s the best resource to find answers to these things on myself? The wiki seems to frequently lag behind and I often end up here in discourse when I search for it. Is there a better way?

Hey, found out what the problem was. It was this issue:

The test that was failing was that it couldn’t find /bin/sh

Which of the solutions in the Github Issue solved the problem for you? I’m reading through it, but have not yet been able to fix it. Switching the whole system to master is not what I want to do

This solution in particular was helpful for me:

It does not require switching to master

This is a bit late now, but I passed command line options like so: NixOS: nixos-rebuild fails with memory allocation for gzip -d · Issue #124215 · NixOS/nixpkgs · GitHub

Doubt many other people will run into this now though, but hope you got it sorted.