refactor(core): support tiered layer nodes (#33937)

packages/opencode/test/effect/layer-node.test.ts

@@ -0,0 +1,82 @@
+import { describe, expect, test } from "bun:test"
+import { Context, Effect, Layer } from "effect"
+import { LayerNode } from "@opencode-ai/core/effect/layer-node"
+
+class Value extends Context.Service<Value, { readonly value: string }>()("test/LayerNodeValue") {}
+class Greeting extends Context.Service<Greeting, { readonly value: string }>()("test/LayerNodeGreeting") {}
+class Left extends Context.Service<Left, { readonly value: string }>()("test/LayerNodeLeft") {}
+class Right extends Context.Service<Right, { readonly value: string }>()("test/LayerNodeRight") {}
+
+const tiers = LayerNode.tiers(["app"])
+const make = tiers.make("app")
+const valueLayer = Layer.succeed(Value, Value.of({ value: "production" }))
+const greetingLayer = Layer.effect(
+  Greeting,
+  Effect.map(Value, (value) => Greeting.of({ value: `hello ${value.value}` })),
+)
+const value = make({ service: Value, layer: valueLayer, deps: [] })
+const greeting = make({ service: Greeting, layer: greetingLayer, deps: [value] })
+
+describe("layer node", () => {
+  test("builds an untiered graph", async () => {
+    const value = LayerNode.make({ service: Value, layer: valueLayer, deps: [] })
+    const greeting = LayerNode.make({ service: Greeting, layer: greetingLayer, deps: [value] })
+    const program = Effect.map(Greeting, (item) => item.value).pipe(Effect.provide(LayerNode.buildLayer(greeting)))
+    expect(await Effect.runPromise(program)).toBe("hello production")
+  })
+
+  test("builds a dependency graph", async () => {
+    const program = Effect.map(Greeting, (item) => item.value).pipe(
+      Effect.provide(LayerNode.buildLayer(greeting, { tiers })),
+    )
+    expect(await Effect.runPromise(program)).toBe("hello production")
+  })
+
+  test("replaces a layer by identity", async () => {
+    const replacement = Layer.succeed(Value, Value.of({ value: "simulation" }))
+    const program = Effect.map(Greeting, (item) => item.value).pipe(
+      Effect.provide(LayerNode.buildLayer(greeting, { tiers, replacements: [LayerNode.replace(valueLayer, replacement)] })),
+    )
+    expect(await Effect.runPromise(program)).toBe("hello simulation")
+  })
+
+  test("replaces every use of the same layer", async () => {
+    const leftLayer = Layer.effect(
+      Left,
+      Effect.map(Value, (item) => Left.of({ value: item.value })),
+    )
+    const rightLayer = Layer.effect(
+      Right,
+      Effect.map(Value, (item) => Right.of({ value: item.value })),
+    )
+    const left = make({ service: Left, layer: leftLayer, deps: [value] })
+    const right = make({ service: Right, layer: rightLayer, deps: [value] })
+    const replacement = Layer.succeed(Value, Value.of({ value: "replaced" }))
+    const layer = LayerNode.buildLayer(LayerNode.group([left, right]), {
+      tiers,
+      replacements: [LayerNode.replace(valueLayer, replacement)],
+    })
+    const program = Effect.gen(function* () {
+      return [(yield* Left).value, (yield* Right).value]
+    }).pipe(Effect.provide(layer))
+    expect(await Effect.runPromise(program)).toEqual(["replaced", "replaced"])
+  })
+
+  test("does not acquire an unused replacement", async () => {
+    let acquisitions = 0
+    const other = Layer.succeed(Value, Value.of({ value: "other" }))
+    const replacement = Layer.effect(
+      Value,
+      Effect.sync(() => {
+        acquisitions++
+        return Value.of({ value: "replacement" })
+      }),
+    )
+    await Effect.runPromise(
+      Effect.map(Greeting, (item) => item.value).pipe(
+        Effect.provide(LayerNode.buildLayer(greeting, { tiers, replacements: [LayerNode.replace(other, replacement)] })),
+      ),
+    )
+    expect(acquisitions).toBe(0)
+  })
+})