D042 - The corpus is a pinned manifest

Status: decided Date: 2026-09-26

corpus/sources.toml lists third-party homebrew by source, licence and per-asset hash, and orbistoun-corpus fetches the bytes into the titles library. The manifest is tracked; the bytes never are. CI does not fetch on every run.

Why: a real guest getting further is the measure of progress, and it needs guests nobody here wrote. Pinning by hash keeps the corpus reproducible past the day a branch moves. Downloading is not redistributing, and a red build caused by someone else's repository moving teaches people to ignore red builds.

Rejected:

• Tracking the binaries: somebody else's guest bytes in the tree.
• Pinning by branch: not reproducible within a month.
• Clone-and-compile sources: every developer needs a cross-compiler.