3tears-enforcement 0.18.0

Static-analysis enforcement scanners for the 3tears ecosystem (cache primitive contract, underscore-access discipline, codebase conventions, etc.)

3tears-enforcement

Shared static-analysis enforcement scanners for the 3tears ecosystem.

What this package does

Each module under threetears.enforcement.<domain> ships an AST-based scanner that enforces a single architectural invariant across a Python source tree. Consumer repos import the scanner, inject their per-repo configuration (allowlists, exemption files, src roots), and run it from a thin pytest test class.

This replaces a previous pattern in which the same enforcement test files were vendored verbatim across multiple repos with manual sync requirements. The shared package eliminates duplication and drift while keeping per-repo configuration where it belongs.

Domains

Module	Invariant enforced
cache	Every stateful data surface routes through BaseCollection; no bespoke SQLiteBackend wrappers; no direct pool access to Collection-backed tables; every migration-defined table has a Collection class.
underscore_access	Underscore prefix is a stability contract: no cross-module private import, no cross-class protected access, modules with public names have __all__, no subclass shadowing of base private attributes, no __all__ listing private names.
codebase_conventions	No bare print(), no stdlib logging.getLogger (use threetears.observe), from __future__ import annotations required, return type annotations required.
coercion_coverage	Tool subclasses override execute, never run, preserving the normalize_kwargs → execute input-coercion path.
dict_state_detection	No raw dict/OrderedDict persistent state in __init__; use SQLiteBackend (L1) or NATS KV for shared state.
logger_coverage	Every production module declares a module-level log = get_logger(__name__) unless explicitly exempt.
migration_yugabyte_safety	Migration shapes are yugabyte-safe per threetears.core.data.migrations.enforcement.
nats_wrapper_usage	All nats-py imports route through threetears.nats.NatsClient; no direct import nats.
no_silent_swallow	Exception handlers must log, re-raise, or carry # NOSILENT: <reason>.
no_stdlib_logging	No production module imports stdlib logging directly; use threetears.observe.

How to use it

Each domain exposes a configuration dataclass and a high-level runner:

# tests/enforcement/test_cache_primitive_usage.py
from pathlib import Path
from threetears.enforcement.cache import CacheEnforcementConfig, run_cache_enforcement

_CONFIG = CacheEnforcementConfig(
    repo_root=Path(__file__).parents[2],
    allowed_sqlite_construction_sites=frozenset({
        "packages/registry/src/threetears/registry/l1_cache.py",
    }),
    collection_table_allowlist={
        "memories": "MemoriesCollection",
        # ... per-repo
    },
    migration_table_allowlist=frozenset({"_schema_migrations"}),
    exemptions_path=Path(__file__).parent / "_cache_exemptions.txt",
    enforcement_mode_env_var="CACHE_ENFORCEMENT_MODE",
)

class TestCachePrimitiveUsage:
    def test_no_bespoke_sqlite_backend_construction(self) -> None:
        run_cache_enforcement(_CONFIG, walker="sqlite_construction")

    def test_no_bespoke_cache_wrapper_classes(self) -> None:
        run_cache_enforcement(_CONFIG, walker="wrapper_class")

    def test_no_direct_pool_access_to_collection_tables(self) -> None:
        run_cache_enforcement(_CONFIG, walker="pool_access")

    def test_all_tables_have_collections(self) -> None:
        run_cache_enforcement(_CONFIG, walker="missing_collection")

Per-repo exemption files (e.g., _cache_exemptions.txt) stay in the consumer repo's tests/enforcement/ directory. The package's parse_exemptions_with_rationale reads them at test time.

How to onboard a new repo

1. Add 3tears-enforcement as a dev dependency.
2. For each domain you want to enforce: create a thin shell test file at tests/enforcement/test_<domain>.py following the pattern above. Inject your repo's allowlists/exemptions.
3. Create per-domain exemption files at tests/enforcement/_<domain>_exemptions.txt if needed. Every exemption requires a preceding # rationale: <specific reason> line.
4. Run pytest tests/enforcement/ to verify the scanners work against your tree.

How to add a new enforcement domain

1. Create src/threetears/enforcement/<domain>/ with walkers.py, config.py, runner.py, and __init__.py.
2. Use common/ helpers (ast_helpers, repo_layout, pyproject_discovery, inheritance, exemptions, modes, violations, reports). Do not duplicate scaffolding.
3. Walkers return list[Violation]. Configs are frozen dataclasses. Runners orchestrate walker → exemption-application → mode-resolution → report.
4. Write unit tests in tests/<domain>/.
5. Document the domain in this README.