nixpkgs/.github/ISSUE_TEMPLATE/unreproducible_package.md

name	about	title	labels	assignees
Unreproducible package	A package that does not produce a bit-by-bit reproducible result each time it is built		0.kind: enhancement 6.topic: reproducible builds

Building this package twice does not produce the bit-by-bit identical result each time, making it harder to detect CI breaches. You can read more about this at https://reproducible-builds.org/ .

Fixing bit-by-bit reproducibility also has additional advantages, such as avoiding hard-to-reproduce bugs, making content-addressed storage more effective and reducing rebuilds in such systems.

Steps To Reproduce

nix-build '<nixpkgs>' -A ... --check --keep-failed

You can use diffoscope to analyze the differences in the output of the two builds.

To view the build log of the build that produced the artifact in the binary cache:

nix-store --read-log $(nix-instantiate '<nixpkgs>' -A ...)

Additional context

(please share the relevant fragment of the diffoscope output here, and any additional analysis you may have done)