Substrate-level gate: same @client fixture registered in both backends
emits equivalent schemas, therefore the codegen produces equivalent
TypeScript regardless of which backend the frontend is generated against.
Catches adapter symmetry problems (Pydantic→OpenAPI converter divergence,
metadata leakage, ordering non-determinism) without docker, browser, or
Playwright.
What ships:
backends/mizan-fastapi/src/mizan_fastapi/schema.py — build_schema():
- Builds OpenAPI 3.0 from registered Mizan functions, mirroring the
shape mizan-django's export emits.
- Drives FastAPI's native OpenAPI generation by registering a stub POST
endpoint per function with its Input/Output Pydantic models, then
appends x-mizan-functions and x-mizan-contexts extensions.
- Param-elevation logic mirrors mizan-django/src/mizan/export/__init__.py
exactly (sharedBy tracking, required iff every function in context has
the param).
- snake_to_camel and metadata field shapes match Django for byte-equality
on the AFI surface.
tests/afi/ — the conformance harness:
- fixture.py: 5 @client functions covering the protocol axes (plain,
context, mutation+affects). No channels/forms — those aren't AFI-common.
- django_app/: minimal Django project (settings, urls, AppConfig.ready
registers the fixture). manage.py adds tests/afi/ to sys.path so both
backends import the same fixture module.
- fastapi_app.py: thin make_app() that registers fixture and mounts router.
- schema_normalizer.py: drops backend-specific framing — Ninja-vs-FastAPI
envelope differences (info/servers/tags), Django-only function fields
(form metadata), x-mizan-channels. Plus afi_subset() and
function_io_schemas() helpers for narrower comparisons.
- test_codegen_parity.py: three gates
1. x-mizan-functions match across backends
2. x-mizan-contexts match across backends
3. Per-function Input/Output OpenAPI schemas match (what codegen feeds
to openapi-typescript for type generation)
The full normalized OpenAPI envelopes do diverge — FastAPI adds
HTTPValidationError, the two converters wrap things slightly differently
in non-AFI-essential ways. That's not in the test scope. The codegen
only consumes x-mizan-functions, x-mizan-contexts, and the per-function
type schemas; those are what the test gates.
Makefile: test-afi target added; rolls into the test aggregate.
Verified: 3/3 conformance tests pass. Other surfaces unaffected —
mizan-core 15/15, mizan-django 348 pass, mizan-fastapi 11/11.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
98 B
98 B