Contracts

census-owner-adoption-contract.md

Contract: Census Owner-Adoption Invariants (#3121 / C-011)

This mission is a test-isolation refactor — it exposes no new runtime interface. The binding "contracts" it must honor are the existing census invariants and the canonical-owner behaviour.

Invariants the fix must preserve (read-only — enforced by tests/architectural/)

1. Census equality (test_spec_kitty_home_pin_census.py, t023): census == anchor and discover(tests) − E == anchor. The fix restores this by making discover() return to the frozen 40-member class — NOT by editing census, anchor, or members.json. 2. Set-equality, never containment (t022–t026): no test is weakened; equalities stay ==. 3. Exempt-set arity (_home_pin_exempt.py): E remains tuple[Exempt, Exempt]; no third entry (mypy --strict clean). 4. Ratchet still bites (NFR-001): injecting any new SPEC_KITTY_HOME→<tmp_path>/home pin makes the census red. Verified by the T003 red-injection proof.

Owner-adoption contract (consumed, not modified)

that requests it by parameter and writes no setenv of its own gets a fresh per-test <tmp_path>/home (mkdir'd) and adds no census row.

the fix MUST delete the test's setenv, not merely add the fixture.

  • canonical_home (tests/conftest.py) is the single exempt SPEC_KITTY_HOME owner. A test
  • A consumer that requests the owner and keeps its own pin still counts as a member — so

Scope boundary

#3121 (operator halt-and-rescope); the broader R1b convergence is deferred.

  • Addresses only the acute arch_shard_3 red owed to the new #3497 pin. Does not close
  • No production/behaviour change (sync/layout_generation.py untouched — C-005).