3tears-enforcement

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

Adopting invalidation_listener in a repo that already runs a local copy. Three things change, and only the first is obvious.

1. The exemption format. The hub's pre-shared walker keyed by BARE MODULE PATH (src/aibots/gateway/acl.py). The shared parser wants a path:line:symbol triple and rejects anything else with ExemptionError, so an unmigrated file does not degrade -- it aborts the domain. Rewrite each entry as <path>:*:<registry-spelling>, keeping its # rationale: line. * means "any line in that file", which is what you want: keying an exemption to a line number silently stops matching when the line moves.
2. minimum_live_registries is yours to supply, and it is REQUIRED with no default. Count the L2-live registries your repo actually wires and put that number in the shell. It is the floor that makes a green report mean anything.
3. Repo-specific shell assertions do not come across. A local walker typically carries checks the shared domain has no equivalent for -- which processes must be in scope, that an L1-only registry is not dragged in, detector positive/negative cases. Those are yours to keep: port them into the thin shell rather than assuming the domain replaced them, because deleting the local file deletes them silently.

This note describes a one-time migration and should be deleted once every consumer has adopted the domain. Tracked as ENF-7WQ2 in the 14-eng-ai-bot backlog, which is this family's backlog of record -- not this repo's, so do not go looking for it here.

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, collection_registry, repo_layout, pyproject_discovery, inheritance, exemptions, modes, violations, reports). Do not duplicate scaffolding. Two in particular, because both have already been re-implemented in this package rather than imported:
   • ast_helpers owns the dotted-name spelling family -- dotted, callee_names, receiver, argument_spellings. If you are about to write a loop that walks an ast.Attribute chain accumulating segments, it exists. Three copies of that walk shipped here before it was shared, each differing by one detail that turned out to be a parameter (dotted's unwrap_subscript is the survivor).
   • collection_registry owns "which CollectionRegistry names are L2-live" -- take the answer from there rather than re-deriving it. CLIENT_SPELLINGS is a heuristic list that grows, so a second copy goes stale silently while still compiling.
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.