refactor: destroy Storage facades (#21956)

packages/opencode/specs/effect-migration.md

@@ -308,3 +308,32 @@ Current raw fs users that will convert during tool migration:
 - [ ] `util/flock.ts` — file-based distributed lock with heartbeat → Effect.repeat + addFinalizer
 - [ ] `util/process.ts` — child process spawn wrapper → return Effect instead of Promise
 - [ ] `util/lazy.ts` — replace uses in Effect code with Effect.cached; keep for sync-only code
+
+## Destroying the facades
+
+Every service currently exports async facade functions at the bottom of its namespace — `export async function read(...) { return runPromise(...) }` — backed by a per-service `makeRuntime`. These exist because cyclic imports used to force each service to build its own independent runtime. Now that the layer DAG is acyclic and `AppRuntime` (`src/effect/app-runtime.ts`) composes everything into one `ManagedRuntime`, we're removing them.
+
+### Process
+
+For each service, the migration is roughly:
+
+1. **Find callers.** `grep -n "Namespace\.(methodA|methodB|...)"` across `src/` and `test/`. Skip the service file itself.
+2. **Migrate production callers.** For each effectful caller that does `Effect.tryPromise(() => Namespace.method(...))`:
+   - Add the service to the caller's layer R type (`Layer.Layer<Self, never, ... | Namespace.Service>`)
+   - Yield it at the top of the layer: `const ns = yield* Namespace.Service`
+   - Replace `Effect.tryPromise(() => Namespace.method(...))` with `yield* ns.method(...)` (or `ns.method(...).pipe(Effect.orElseSucceed(...))` for the common fallback case)
+   - Add `Layer.provide(Namespace.defaultLayer)` to the caller's own `defaultLayer` chain
+3. **Fix tests that used the caller's raw `.layer`.** Any test that composes `Caller.layer` (not `defaultLayer`) needs to also provide the newly-required service tag. The fastest fix is usually switching to `Caller.defaultLayer` since it now pulls in the new dependency.
+4. **Migrate test callers of the facade.** Tests calling `Namespace.method(...)` directly get converted to full effectful style using `testEffect(Namespace.defaultLayer)` + `it.live` / `it.effect` + `yield* svc.method(...)`. Don't wrap the test body in `Effect.promise(async () => {...})` — do the whole thing in `Effect.gen` and use `AppFileSystem.Service` / `tmpdirScoped` / `Effect.addFinalizer` for what used to be raw `fs` / `Bun.write` / `try/finally`.
+5. **Delete the facades.** Once `grep` shows zero callers, remove the `export async function` block AND the `makeRuntime(...)` line from the service namespace. Also remove the now-unused `import { makeRuntime }`.
+
+### Pitfalls
+
+- **Layer caching inside tests.** `testEffect(layer)` constructs the Storage (or whatever) service once and memoizes it. If a test then tries `inner.pipe(Effect.provide(customStorage))` to swap in a differently-configured Storage, the outer cached one wins and the inner provision is a no-op. Fix: wrap the overriding layer in `Layer.fresh(...)`, which forces a new instance to be built instead of hitting the memoMap cache. This lets a single `testEffect(...)` serve both simple and per-test-customized cases.
+- **`Effect.tryPromise` → `yield*` drops the Promise layer.** The old code was `Effect.tryPromise(() => Storage.read(...))` — a `tryPromise` wrapper because the facade returned a Promise. The new code is `yield* storage.read(...)` directly — the service method already returns an Effect, so no wrapper is needed. Don't reach for `Effect.promise` or `Effect.tryPromise` during migration; if you're using them on a service method call, you're doing it wrong.
+- **Raw `.layer` test callers break silently in the type checker.** When you add a new R requirement to a service's `.layer`, any test that composes it raw (not `defaultLayer`) becomes under-specified. `tsgo` will flag this — the error looks like `Type 'Storage.Service' is not assignable to type '... | Service | TestConsole'`. Usually the fix is to switch that composition to `defaultLayer`, or add `Layer.provide(NewDep.defaultLayer)` to the custom composition.
+- **Tests that do async setup with `fs`, `Bun.write`, `tmpdir`.** Convert these to `AppFileSystem.Service` calls inside `Effect.gen`, and use `tmpdirScoped()` instead of `tmpdir()` so cleanup happens via the scope finalizer. For file operations on the actual filesystem (not via a service), a small helper like `const writeJson = Effect.fnUntraced(function* (file, value) { const fs = yield* AppFileSystem.Service; yield* fs.makeDirectory(path.dirname(file), { recursive: true }); yield* fs.writeFileString(file, JSON.stringify(value, null, 2)) })` keeps the migration tests clean.
+
+### Migration log
+
+- `Storage` — migrated 2026-04-10. One production caller (`Session.diff`) and all storage.test.ts tests converted to effectful style. Facades and `makeRuntime` removed.