rebar3 itself supports reproducible builds via lock files. Applying patches like this instead of embracing the right way that the upstream designed for this exact purpose is just ignorance.

I would be totally cool with any incompatible patches that distro makes for its needs, as long as the binary is renamed. But they shipped a broken binary and called it rebar3. Not "rebar3-nix", but "rebar3". People try using this binary for development and it doesn't work, they go to the upstream and the upstream spends time investigating someone else's hacks.