nixception v0.6.0

nixception 0.6.0

This release fixes a cache-parity bug: actions built through nix develop
could fail to hit the cache of an otherwise byte-identical action built
through nix build, because of a Nix daemon quirk that had nothing to do
with the actions actually differing.

Highlights

• Discovered /nix/store/… paths are always input sources, never resolved
  to a deriver. Preparing an action's derivation used to ask the Nix daemon
  for each discovered store path's deriver, and reference that deriver
  instead of the path itself when one was found — more precise, but it
  turned out to be unreliable rather than merely unavailable. Inside a
  recursive-nix sandboxed build (every real nix build action goes through
  one), the daemon nixception talks to is Nix's own RestrictedStore, which
  unconditionally strips deriver info from every reply as impure — so a real
  build's actions always resolved paths as plain sources. A caller outside
  that sandbox (nix develop, talking to the host daemon directly) could
  resolve some of the very same paths to derivers instead, giving an
  otherwise identical action a different derivation shape — and hash — than
  the one a real build produced, defeating the cache across that boundary.
  Every discovered path is now an input source, unconditionally: less
  precise, but deterministic from any calling context, with no daemon
  round-trip (and its context-dependent answer) involved.

See the changelog for the full list.

Licensing

The nixception sources are licensed under Apache-2.0. Binary distributions
of the server are additionally governed by GPL-3.0 through the statically
linked nix-compat crate — see NOTICE for full attribution and
licensing details.

Full Changelog: v0.5.0...v0.6.0