The Mizan codegen substrate moves off JavaScript template-literal emission
onto a compiled Rust binary that consumes the same OpenAPI + x-mizan-* IR
the JS substrate consumed. Three structural wins fall out of one move:
1. Moat closes. The codegen logic (how `affects` becomes auto-invalidation,
how named contexts collapse onto bundled fetches, how the registry-to-
Provider mapping is shaped) ships compiled instead of as source bytes
in every consumer's node_modules.
2. Pattern F (lines.push append-walls) becomes structurally unauthorable.
The emit substrate is askama templates in templates/<target>/*.j2 —
actual target-language files with {{ ... }} substitution markers,
syntax-highlighted natively, type-checked against the render context
structs at compile time. The Rust emit modules build typed render
contexts and call .render(); no string-builder surface exists.
3. OpenAPI `default`-bearing fields now emit as non-optional in TS / Python
/ Rust — the server always populates them, so consumer code reads them
without nullable checks. Surfaced by Blazr's typecheck on regeneration.
Layout:
frontends/mizan-rust/ — Rust port of @mizan/base; #[cfg(feature="pyo3")]
exposes PyMizanClient for the Python target.
protocol/mizan-codegen/ — codegen binary source + askama templates.
protocol/mizan-generate/ — npm-package shim. bin/launcher.mjs dispatches
to the platform-appropriate prebuilt binary.
Old generator/ JS tree deleted.
tests/rust/ — wire-parity drivers. drive_kernel exercises
raw client.call() / fetch_context(); drive_emitted
exercises the typed crate the codegen emits.
tests/afi/afi_codegen_app.py — codegen entrypoint module (imports + registers).
backends/mizan-fastapi/.../schema.py — adds outputNullable so the Rust
codegen can wrap T | None responses in Option<T>.
Verification:
- 20 mizan-codegen tests green (IR deserialization, byte-equivalent
parity vs JS baseline for stage1/rust/python/react/vue/svelte,
structural test for channels).
- tests/rust/run_wire_parity.py — 12/12 probes green via the Rust binary
driving the FastAPI fixture end-to-end.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The codegen consumes a schema from any backend and emits typed client
code for any frontend — it doesn't belong inside a backend adapter.
That placement was historical sediment from when there was only a
Django backend; it predates the AFI generalization.
New top-level slot: `protocol/` for protocol-level tooling. Tree is
now:
backends/ server protocol adapters
frontends/ client kernel + per-framework adapters
cores/ shared language-level primitives
protocol/ protocol-level tooling
workers/ runtime workers / bridges
Codegen moves to `protocol/mizan-generate/`. Same file layout under
`generator/` (cli.mjs, lib/), preserved via git mv.
Package metadata cleaned up:
- name: "generate" (placeholder) → "mizan-generate"
- description filled in
- type: module (cli.mjs is .mjs ESM, was previously declared "commonjs")
- bin entry added so `npx mizan-generate --config <config.mjs>` works
once the package is published, instead of `node path/to/cli.mjs`.
Path-reference fixups:
- backends/mizan-django/README.md: `node path/to/...` → `npx mizan-generate`
- backends/mizan-fastapi/README.md: same
- ISSUES.md: file paths in three issue entries
- CLAUDE.md: codegen description + Package Layout section refreshed
(added protocol/, mizan-fastapi entry, mizan-python entry)
- docs/AFI_ARCHITECTURE.md: Package Layout refreshed identically
Verified codegen runs from new location: regenerated the FastAPI
example harness's api/ output, identical to pre-move.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
