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Ekklesia/docs/architecture/repository-boundaries.md
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feat: build module UI into its declared browser artifact
ADR 0022 defined what a module UI is and selected React and TypeScript
as the authoring model, but closed by recording that it was not buildable
end to end: `browser.json` preserves JSX, bundler plugins are denied, and
nothing turned a module's `.tsx` into the artifact its manifest declares.
This closes exactly that gap.

esbuild produces the artifact. It was already the right answer before it
was chosen: this workspace resolves esbuild 0.28.1 through Vite/Vitest
today and `pnpm-workspace.yaml` already carries `allowBuilds: esbuild`,
so the pinned dependency adds no second copy and no new trust decision.
It is also the smallest tool that covers TSX, ESM, browser platform,
bundling, source maps, and a define-time constant with no plugin
ecosystem. Vite library mode would drag in `@vitejs/plugin-react`, which
the module boundary denies on purpose; `tsc` alone cannot bundle, so its
output would carry bare `react/jsx-runtime` imports no browser resolves.

React is bundled, not externalized. That follows from ADR 0022 rather
than from convenience: `mount()` was made the ABI precisely so React
would not be part of the host contract, and externalizing it would
reverse that through the build system — every host would have to supply
a compatible React, and a standalone host might not use React at all.
The cost is real and accepted: duplicate runtimes and a ~570 KB
unminified artifact. Sharing one runtime later is a build optimization
that cannot change the contract, because the contract is a mount
function.

Output is browser ESM at `es2022`, unminified so an operator can review
what they install, with `process.env.NODE_ENV` substituted — React reads
it at module scope and would otherwise touch a Node global that does not
exist in a browser. The output path is read from the module's own
manifest rather than a build convention, so declared and produced
artifacts cannot drift, and it is validated with the same
`packageRelativePathSchema` discovery enforces, so a build can never
write where discovery would later reject.

`@ekklesia/module-ui-build` owns every option; modules own none. It uses
the existing `tooling` role that modules could already depend on, so this
pass required no boundary relaxation at all. Its `bin` points at a
committed launcher rather than compiled output because pnpm links bins
during install, before Turborepo builds anything — a bin targeting
`dist/cli.js` fails to link on a fresh clone and breaks every module's UI
build in CI. A module with no `entrypoints.ui` is not an error; the CLI
reports nothing to build and exits zero, so one script serves both kinds
of module.

Styling is React inline style objects. A stylesheet import fails the
build rather than emitting a sidecar `.css` that no manifest declares and
no host loads — an undeclared asset would appear to work in tests and
silently do nothing in a real host.

`templates/module` is the canonical example and now ships optional UI.
Its tests build the artifact from source, validate it with
`parseModuleUiExport`, mount it into a real DOM, assert the rendered
output, and unmount it; the artifact is rebuilt per run so the proof can
never pass against stale output, and `dist/` stays gitignored. Because
verify runs both `pnpm test` and `pnpm build`, a UI that cannot be
produced fails CI through two independent paths.

One correction worth stating plainly: the UI TypeScript project declares
`"types": []`, and a UI file referencing `process` does fail in
isolation, but TypeScript still pulls Node globals in transitively — a
file importing `@ekklesia/module-ui-sdk` reaches `@ekklesia/contracts`
and through its Zod and Drizzle types `process.env` typechecks again.
The docs and ADR describe this as the convention it is rather than the
guard it is not.

Core is untouched. Building is an authoring step; discovery still only
validates the artifact a module shipped and never executes or produces
one.

Co-Authored-By: Claude Opus 5 <[email protected]>
2026-08-21 21:24:18 -05:00

4.9 KiB

Repository boundaries

These rules map platform ownership to filesystem and package boundaries. The executable check is pnpm boundaries; CI must reject violations.

Area Owns May depend on
apps/* Thin deployable composition roots Public Core APIs, generated bootstrap, or a surface as required by the app
core Feature-agnostic platform implementations Public contracts and external infrastructure libraries
modules/* Domain capability, data, and the module's own UI Module SDK, module UI SDK, public contracts, React, and external backend libraries
surfaces/* UI, renderers, navigation, and interaction Surface SDK, API/auth clients, public contracts, and design packages
builders/* Declarative surface composition tooling Builder/surface SDKs and public contracts
packages/* Explicitly scoped SDKs, contracts, clients, design, testing, or tooling Only dependencies appropriate to the package's declared level
templates/module A small example backend module The same dependencies allowed for any module

Mandatory rules

  • Core never imports a feature module, surface, Builder implementation, or app.
  • A module never imports Core implementations, another module, a surface, Builder code, or an app.
  • A module may own UI (ADR 0021) and authors it in React and TypeScript (ADR 0022). A module may therefore contain .tsx source and depend on react, react-dom, and @ekklesia/module-ui-sdk. It still cannot contain .jsx, stylesheets, single-file components, Astro/Marko/MDX/HTML views, or SVG presentation assets, and cannot depend on any other UI framework (including react-router-dom, react-native, and @vitejs/plugin-react) or on shared UI-role packages. A module needs no bundler plugin: @ekklesia/module-ui-build — a tooling package, a role modules could already depend on — owns the entire module UI build (ADR 0023). An unsupported framework aliased behind an allowed name is resolved and rejected by its real target.
  • Module UI source is subject to the identical layer rules as module backend source: it may not import Core, an app, a surface, a builder, or another module. Core still owns the containing application shell and all platform policy, and module UI reaches the host only through @ekklesia/module-ui-sdk.
  • A surface never imports Core or a feature module. It uses public API/client contracts.
  • Separate surfaces do not import each other's internals.
  • Builder code composes contracts and surface renderer identifiers; it does not import module or surface internals.
  • Contract and SDK packages cannot depend upward on implementations.
  • Workspace package consumers use declared exports, not private subpaths.
  • Every internal dependency uses a workspace: range and every imported workspace package is declared by the consumer.
  • Workspace aliases are forbidden because they obscure package ownership in the dependency graph.
  • Workspace package names are unique and shared packages declare a recognized architectural role.
  • Circular source and workspace-package dependencies are rejected.
  • Cross-module data access uses services, events, capabilities, or opaque identifiers rather than direct table imports and foreign keys. Modules may not import another module's Drizzle tables, columns, relations, schema entrypoint, or migration internals.

The boundary test suite includes intentionally invalid fixture graphs. This proves that the guard rejects every currently machine-checkable repository rule even before production packages fill every directory. The UI guard rejects component, view, template, stylesheet, shared UI-role, and common UI-framework dependencies inside modules. This deny list is defense in depth; package review remains required when adopting a new frontend technology. ADR 0022 narrowed the guard precisely rather than removing it: React was un-denied, every other framework stayed denied, and the layer rules were untouched.

The Phase 3 schema validator complements source boundaries by checking table ownership, foreign-key targets, and physical table namespaces in compiled Drizzle metadata. Offline migration validation checks each module's packaged Drizzle inventory and policy contract, while deliberately making no claim that opaque SQL ownership can be proven without PostgreSQL-aware analysis.

Generated code

Generated artifacts are reproducible outputs with a named generator and validation step. A generated module bootstrap under the root generated/ boundary may import discovered module entry points, and apps may import that generated bootstrap. Handwritten app and Core code still cannot import feature modules directly. Generated files are never an excuse for a hand-maintained central module registry.