- Removed §IX (OSS / Cloud kernel-product split) — business strategy belongs
in MR-738, not the technical invariants doc.
- Filled the §IV (Additivity / migration) placeholder with five evolution
invariants.
- Reframed §I to be substrate-agnostic: invariants are about respecting any
substrate; Lance / DataFusion are noted as the current chosen substrate
rather than as the invariant itself.
- Added §VI Database guarantees (12 invariants): atomicity, schema integrity,
isolation, durability, causal consistency, determinism, idempotency, no
silent loss, bounded operations, failure scope, crash recovery, consistency
model.
- Added §II.8 wire-protocol agnosticism (kernel transport-agnostic,
Flight/HTTP at the server boundary).
- Reframed §VII as "Current architectural patterns" — explicitly distinct
from invariants. Each pattern entry now names the underlying invariant it
realizes (reconciler / Union / mutations-wrap-reads / SIP / factorize /
stable row IDs / rank columns / policy predicates / Source).
- Pulled specific config defaults out of §VI (timeouts, memory caps);
invariant is that bounds exist, values live in docs/constants.md.
- Split §IX deny-list into "invariant violations" (high bar) and "pattern
violations" (overridable with justification).
- Added status legend: decided / open — see MR-X / aspirational. Annotated
invariants and patterns that are not yet upheld in current code.
- Updated review checklist (§X) to cover database-guarantee dimensions and
the wire-protocol / Source / patterns sections.
- Updated Living Document policy (§XI) to spell out how to revise patterns,
resolve open invariants, and lift aspirational annotations.
Source tickets: MR-737, MR-744, MR-765, MR-694 family, MR-722/MR-725.
A standing reference for invariants that hold across storage, engine,
server, schema, indexing, observability, and the OSS/Cloud split. Used
to check RFCs and PRs against the substrate boundaries (don't rebuild
what Lance gives us), layering rules (one trait boundary per layer),
distributability constraints (Send+Sync, location-neutral IR), honesty
expectations (estimate-vs-actual, bounded failure modes), unified
patterns (reconciler, Union polymorphism, SIP, factorize), the §IX
deny-list, and the §X review checklist.
§IV (additivity / migration) and §VIII (OSS/Cloud kernel-product split)
are referenced but not yet drafted — flagged as placeholders pending
upstream fill-in.
AGENTS.md surfaces it from the topic index, the always-on rules
section, and the maintenance contract; the deny-list is also inlined
there as a fast-pass review filter so it stays in scope every turn.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
