Files
mizan/tests/afi/test_codegen_parity.py
Ryth Azhur 3aafec6dd4 A channel's message slots are named from the client, on every backend
The IR called them react-message and django-message, so a FastAPI channel had
to declare a DjangoMessage. They are client-message and server-message now,
and the direction words hold wherever a channel is declared: Params /
ClientMessage / ServerMessage, with mizan-core deriving <Pascal>Params and
friends so no backend names a type itself. Django's ReactChannel and
FastAPI's ReactChannel are both Channel.

mizan-fastapi never registered a channels extension, so build_ir() emitted no
channel at all and every payload type was invisible to codegen. It registers
one now. RegistryExtension is an ABC requiring all(), which is what the IR
reads — an extension that cannot enumerate its registrations no longer exists.

The gate that should have caught the rename could not: tests/afi registered no
channel because mizan-rust had no channel registry to register one in, so a
five-package rename of the wire contract passed byte-parity without a channel
byte crossing it. mizan-rust grows ChannelSlotKind, a CHANNELS slice, a
#[mizan::channel] macro, and KDL emission whose wire_to_pascal matches Python's
split; the AFI fixture now carries a channel with every slot and one with a
single slot, so all three backends prove the contract byte for byte.

MizanChannel held three Option<String> beside three has_*() predicates and
unwrapped them with defaults; it holds an ordered slot vector, so an absent
slot is absent rather than defaulted. The channels target emitted a React
hooks file that a stage1-only consumer could not compile — react emits that
now. The codegen's parity tests byte-compared emitted source against baselines
without ever compiling it: they compile the generated crate and run its tests,
import the generated Python package and call every method, and typecheck each
TypeScript target against a consumer.

Also fixed at source: app_visitor printed its import diagnostic to stdout, the
stream export_mizan_ir writes KDL to, so a failed import silently corrupted the
IR; the apps root was hardcoded to "apps"; _default_literal crashed build_ir on
any non-JSON-serializable field default; Django and mizan-core derived Pascal
names two different ways, disagreeing on every dotted channel name.

ir.py builds a document and renders templates/ir/document.kdl.j2 rather than
appending KDL strings with hand-tracked indentation, and named types resolve to
a fixed point — a model reachable only through a union branch was referenced by
a ref that no type block ever defined.

The rest is the write-gate's own classifiers run over the standing tree:
relative imports, silent swallows, Protocol contracts that should be ABCs,
emitters hand-rendering target source, catch-all arms over closed enums, and
comments narrating the project rather than the code.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-27 14:03:19 -04:00

107 lines
2.8 KiB
Python

"""Byte-equivalence of the Mizan IR (KDL) that mizan-django, mizan-fastapi,
and the Rust mizan-axum backend emit for one shared fixture.
Each adapter is reached the way its own runtime reaches it: Django through
its management command in a subprocess, FastAPI in-process against a cleared
registry, Rust through the `export-ir` bin.
"""
from __future__ import annotations
import os
import subprocess
import sys
from pathlib import Path
import pytest
HERE = Path(__file__).parent
DJANGO_MANAGE = HERE / "django_app" / "manage.py"
RUST_APP_DIR = HERE / "rust_app"
def _fetch_django_ir() -> str:
result = subprocess.run(
[sys.executable, str(DJANGO_MANAGE), "export_mizan_ir"],
capture_output=True,
text=True,
check=False,
env={**os.environ, "PYTHONDONTWRITEBYTECODE": "1"},
)
if result.returncode != 0:
pytest.fail(
f"export_mizan_ir failed:\nstdout:\n{result.stdout}\nstderr:\n{result.stderr}",
)
return result.stdout
def _fetch_fastapi_ir() -> str:
# tests/afi/ must be importable for `fixture` and `fastapi_app` to resolve.
sys.path.insert(0, str(HERE))
try:
from mizan_core.registry import clear_registry
from mizan_core.ir import build_ir
from fastapi_app import make_app
clear_registry()
make_app()
return build_ir()
finally:
sys.path.remove(str(HERE))
def _fetch_rust_ir() -> str:
result = subprocess.run(
[
"cargo", "run",
"--quiet", "--release",
"--manifest-path", str(RUST_APP_DIR / "Cargo.toml"),
"--bin", "export-ir",
],
capture_output=True,
text=True,
check=False,
)
if result.returncode != 0:
pytest.fail(
f"Rust export-ir failed:\nstdout:\n{result.stdout}\nstderr:\n{result.stderr}",
)
return result.stdout
@pytest.fixture(scope="module")
def fastapi_ir() -> str:
return _fetch_fastapi_ir()
@pytest.fixture(scope="module")
def rust_ir() -> str:
return _fetch_rust_ir()
@pytest.fixture(scope="module")
def django_ir() -> str:
return _fetch_django_ir()
def test_fastapi_matches_rust(fastapi_ir: str, rust_ir: str) -> None:
assert fastapi_ir == rust_ir, (
"FastAPI and Rust emit divergent Mizan IR for the same registered "
"functions and channels."
)
def test_django_matches_fastapi(django_ir: str, fastapi_ir: str) -> None:
assert django_ir == fastapi_ir, (
"Django and FastAPI emit divergent Mizan IR for the same registered "
"functions and channels."
)
def test_all_three_match(django_ir: str, fastapi_ir: str, rust_ir: str) -> None:
assert django_ir == fastapi_ir == rust_ir, (
"Three-way IR divergence — see test_django_matches_fastapi and "
"test_fastapi_matches_rust for which pair drifts."
)