nocter-package-cache

Responsibility

Own the filesystem representation and content-integrity contract of one exact package cache entry.

Contract

The crate seals an acquisition-owned package tree with a deterministic content manifest and returns only roots whose current physical tree matches that manifest and its expected exact package identity. Package resolution and package-state publication consume the same verification entry. The crate does not select dependencies, interpret source declarations, fetch packages, publish cache directories, or parse Nocter source.

Internal Responsibilities

• deterministic streaming package-tree hashing
• exact package manifest encoding and validation
• physical file, directory, and symlink validation
• verified exact-package root capability construction

Invariants

• A verified root contains a regular root index.nct and a valid root manifest.
• Every directory and source artifact included in the package tree contributes to one deterministic digest; filesystem enumeration order cannot change it.
• Symlinks, special files, non-Unicode names, and a reserved root-manifest collision are rejected.
• A cache identity mismatch or any content change invalidates the root before resolution can select it.
• Validation never follows a package-owned symlink or mutates package content.