In reply to @fzakaria:one.ems.host
I was going to explore the Katai struct. Is nars.sh and nar-access.sh the only NAR tests?

Hey there,

I am currently investigating nix assertion errors that consistently appear once in a while in our CI. Only MacOS machines are affected by this and the error persists until the nix store is garbage collected. It also only persists on the same user on the machine.

[...]
using cache entry 'fetchToStore:{"fingerprint":"3f0bf132df94785670cb324fbb759e85ff5ad0b6","method":"nar","name":"source","path":"/","store":"/nix/store"}' -> 'null', '/nix/store/72alw9m62226brv4v4m98fqrk31mlp34-source'
store path cache hit for '«github:runtimeverification/k/3f0bf132df94785670cb324fbb759e85ff5ad0b6?narHash=sha256-SYrGoV4PuOWux7d4nYhluWD515%2B9sh0DjAMcEDbREVM%3D»/nix/store/8ck644nfh5mb5dqkzgvqhfbznsk1n4df-source'
custom debug: storePath='72alw9m62226brv4v4m98fqrk31mlp34-source' originalInput.computeStorePath(*state.store)='8ck644nfh5mb5dqkzgvqhfbznsk1n4df-source'
Assertion failed: (!originalInput.getNarHash() || storePath == originalInput.computeStorePath(*state.store)), function copyInputToStore, file ../flake.cc, line 40.

This is the assertion that is violated though the check has since been moved in master. We currently run nix version 2.31.2.

So essentially the two nix store paths differ due to existing and non-existing submodule directories, without their content and also somewhat their parent directory, see:

% diff -qr expected instead | sort
Only in expected/haskell-backend/src/main: native
Only in expected/llvm-backend/src/main: native
Only in expected/web: k-web-theme

Does anybody see what could be wrong here or where to look for bugs in nix? I will probably continue to debug this, but there's a lot going on in nix that I am not aware of yet.