effectify Plugin service (#18570)

2 files changed, 198 insertions, 109 deletions

diff --git a/packages/opencode/specs/effect-migration.md b/packages/opencode/specs/effect-migration.md
index d2ac9ed98..37c70814a 100644
--- a/packages/opencode/specs/effect-migration.md
+++ b/packages/opencode/specs/effect-migration.md
@@ -75,6 +75,31 @@ export const ZodInfo = zod(Info) // derives z.ZodType from Schema.Union
 
 See `Auth.ZodInfo` for the canonical example.
 
+## InstanceState init patterns
+
+The `InstanceState.make` init callback receives a `Scope`, so you can use `Effect.acquireRelease`, `Effect.addFinalizer`, and `Effect.forkScoped` inside it. Resources acquired this way are automatically cleaned up when the instance is disposed or invalidated by `ScopedCache`. This makes it the right place for:
+
+- **Subscriptions**: Use `Effect.acquireRelease` to subscribe and auto-unsubscribe:
+
+```ts
+const cache = yield* InstanceState.make<State>(
+  Effect.fn("Foo.state")(function* (ctx) {
+    // ... load state ...
+
+    yield* Effect.acquireRelease(
+      Effect.sync(() => Bus.subscribeAll((event) => { /* handle */ })),
+      (unsub) => Effect.sync(unsub),
+    )
+
+    return { /* state */ }
+  }),
+)
+```
+
+- **Background fibers**: Use `Effect.forkScoped` — the fiber is interrupted on disposal.
+- **Side effects at init**: Config notification, event wiring, etc. all belong in the init closure. Callers just do `InstanceState.get(cache)` to trigger everything, and `ScopedCache` deduplicates automatically.
+
+The key insight: don't split init into a separate method with a `started` flag. Put everything in the `InstanceState.make` closure and let `ScopedCache` handle the run-once semantics.
 ## Scheduled Tasks
 
 For loops or periodic work, use `Effect.repeat` or `Effect.schedule` with `Effect.forkScoped` in the layer definition.
@@ -127,7 +152,7 @@ Fully migrated (single namespace, InstanceState where needed, flattened facade):
 
 Still open and likely worth migrating:
 
-- [ ] `Plugin`
+- [x] `Plugin`
 - [ ] `ToolRegistry`
 - [ ] `Pty`
 - [ ] `Worktree`
diff --git a/packages/opencode/src/plugin/index.ts b/packages/opencode/src/plugin/index.ts
index 9e294f4f5..1aed1d5f5 100644
--- a/packages/opencode/src/plugin/index.ts
+++ b/packages/opencode/src/plugin/index.ts
@@ -5,140 +5,204 @@ import { Log } from "../util/log"
 import { createOpencodeClient } from "@opencode-ai/sdk"
 import { Server } from "../server/server"
 import { BunProc } from "../bun"
-import { Instance } from "../project/instance"
 import { Flag } from "../flag/flag"
 import { CodexAuthPlugin } from "./codex"
 import { Session } from "../session"
 import { NamedError } from "@opencode-ai/util/error"
 import { CopilotAuthPlugin } from "./copilot"
 import { gitlabAuthPlugin as GitlabAuthPlugin } from "opencode-gitlab-auth"
+import { Effect, Layer, ServiceMap } from "effect"
+import { InstanceState } from "@/effect/instance-state"
+import { makeRunPromise } from "@/effect/run-service"
 
 export namespace Plugin {
   const log = Log.create({ service: "plugin" })
 
+  type State = {
+    hooks: Hooks[]
+  }
+
+  // Hook names that follow the (input, output) => Promise<void> trigger pattern
+  type TriggerName = {
+    [K in keyof Hooks]-?: NonNullable<Hooks[K]> extends (input: any, output: any) => Promise<void>
+      ? K
+      : never
+  }[keyof Hooks]
+
+  export interface Interface {
+    readonly trigger: <
+      Name extends TriggerName,
+      Input = Parameters<Required<Hooks>[Name]>[0],
+      Output = Parameters<Required<Hooks>[Name]>[1],
+    >(
+      name: Name,
+      input: Input,
+      output: Output,
+    ) => Effect.Effect<Output>
+    readonly list: () => Effect.Effect<Hooks[]>
+    readonly init: () => Effect.Effect<void>
+  }
+
+  export class Service extends ServiceMap.Service<Service, Interface>()("@opencode/Plugin") {}
+
   // Built-in plugins that are directly imported (not installed from npm)
   const INTERNAL_PLUGINS: PluginInstance[] = [CodexAuthPlugin, CopilotAuthPlugin, GitlabAuthPlugin]
 
-  const state = Instance.state(async () => {
-    const client = createOpencodeClient({
-      baseUrl: "http://localhost:4096",
-      directory: Instance.directory,
-      headers: Flag.OPENCODE_SERVER_PASSWORD
-        ? {
-            Authorization: `Basic ${Buffer.from(`${Flag.OPENCODE_SERVER_USERNAME ?? "opencode"}:${Flag.OPENCODE_SERVER_PASSWORD}`).toString("base64")}`,
-          }
-        : undefined,
-      fetch: async (...args) => Server.Default().fetch(...args),
-    })
-    const config = await Config.get()
-    const hooks: Hooks[] = []
-    const input: PluginInput = {
-      client,
-      project: Instance.project,
-      worktree: Instance.worktree,
-      directory: Instance.directory,
-      get serverUrl(): URL {
-        return Server.url ?? new URL("http://localhost:4096")
-      },
-      $: Bun.$,
-    }
-
-    for (const plugin of INTERNAL_PLUGINS) {
-      log.info("loading internal plugin", { name: plugin.name })
-      const init = await plugin(input).catch((err) => {
-        log.error("failed to load internal plugin", { name: plugin.name, error: err })
-      })
-      if (init) hooks.push(init)
-    }
-
-    let plugins = config.plugin ?? []
-    if (plugins.length) await Config.waitForDependencies()
-
-    for (let plugin of plugins) {
-      // ignore old codex plugin since it is supported first party now
-      if (plugin.includes("opencode-openai-codex-auth") || plugin.includes("opencode-copilot-auth")) continue
-      log.info("loading plugin", { path: plugin })
-      if (!plugin.startsWith("file://")) {
-        const lastAtIndex = plugin.lastIndexOf("@")
-        const pkg = lastAtIndex > 0 ? plugin.substring(0, lastAtIndex) : plugin
-        const version = lastAtIndex > 0 ? plugin.substring(lastAtIndex + 1) : "latest"
-        plugin = await BunProc.install(pkg, version).catch((err) => {
-          const cause = err instanceof Error ? err.cause : err
-          const detail = cause instanceof Error ? cause.message : String(cause ?? err)
-          log.error("failed to install plugin", { pkg, version, error: detail })
-          Bus.publish(Session.Event.Error, {
-            error: new NamedError.Unknown({
-              message: `Failed to install plugin ${pkg}@${version}: ${detail}`,
-            }).toObject(),
+  // Old npm package names for plugins that are now built-in — skip if users still have them in config
+  const DEPRECATED_PLUGIN_PACKAGES = ["opencode-openai-codex-auth", "opencode-copilot-auth"]
+
+  export const layer = Layer.effect(
+    Service,
+    Effect.gen(function* () {
+      const cache = yield* InstanceState.make<State>(
+        Effect.fn("Plugin.state")(function* (ctx) {
+          const hooks: Hooks[] = []
+
+          yield* Effect.promise(async () => {
+            const client = createOpencodeClient({
+              baseUrl: "http://localhost:4096",
+              directory: ctx.directory,
+              headers: Flag.OPENCODE_SERVER_PASSWORD
+                ? {
+                    Authorization: `Basic ${Buffer.from(`${Flag.OPENCODE_SERVER_USERNAME ?? "opencode"}:${Flag.OPENCODE_SERVER_PASSWORD}`).toString("base64")}`,
+                  }
+                : undefined,
+              fetch: async (...args) => Server.Default().fetch(...args),
+            })
+            const cfg = await Config.get()
+            const input: PluginInput = {
+              client,
+              project: ctx.project,
+              worktree: ctx.worktree,
+              directory: ctx.directory,
+              get serverUrl(): URL {
+                return Server.url ?? new URL("http://localhost:4096")
+              },
+              $: Bun.$,
+            }
+
+            for (const plugin of INTERNAL_PLUGINS) {
+              log.info("loading internal plugin", { name: plugin.name })
+              const init = await plugin(input).catch((err) => {
+                log.error("failed to load internal plugin", { name: plugin.name, error: err })
+              })
+              if (init) hooks.push(init)
+            }
+
+            let plugins = cfg.plugin ?? []
+            if (plugins.length) await Config.waitForDependencies()
+
+            for (let plugin of plugins) {
+              if (DEPRECATED_PLUGIN_PACKAGES.some((pkg) => plugin.includes(pkg))) continue
+              log.info("loading plugin", { path: plugin })
+              if (!plugin.startsWith("file://")) {
+                const idx = plugin.lastIndexOf("@")
+                const pkg = idx > 0 ? plugin.substring(0, idx) : plugin
+                const version = idx > 0 ? plugin.substring(idx + 1) : "latest"
+                plugin = await BunProc.install(pkg, version).catch((err) => {
+                  const cause = err instanceof Error ? err.cause : err
+                  const detail = cause instanceof Error ? cause.message : String(cause ?? err)
+                  log.error("failed to install plugin", { pkg, version, error: detail })
+                  Bus.publish(Session.Event.Error, {
+                    error: new NamedError.Unknown({
+                      message: `Failed to install plugin ${pkg}@${version}: ${detail}`,
+                    }).toObject(),
+                  })
+                  return ""
+                })
+                if (!plugin) continue
+              }
+
+              // Prevent duplicate initialization when plugins export the same function
+              // as both a named export and default export (e.g., `export const X` and `export default X`).
+              // Object.entries(mod) would return both entries pointing to the same function reference.
+              await import(plugin)
+                .then(async (mod) => {
+                  const seen = new Set<PluginInstance>()
+                  for (const [_name, fn] of Object.entries<PluginInstance>(mod)) {
+                    if (seen.has(fn)) continue
+                    seen.add(fn)
+                    hooks.push(await fn(input))
+                  }
+                })
+                .catch((err) => {
+                  const message = err instanceof Error ? err.message : String(err)
+                  log.error("failed to load plugin", { path: plugin, error: message })
+                  Bus.publish(Session.Event.Error, {
+                    error: new NamedError.Unknown({
+                      message: `Failed to load plugin ${plugin}: ${message}`,
+                    }).toObject(),
+                  })
+                })
+            }
+
+            // Notify plugins of current config
+            for (const hook of hooks) {
+              await (hook as any).config?.(cfg)
+            }
           })
-          return ""
-        })
-        if (!plugin) continue
-      }
-      // Prevent duplicate initialization when plugins export the same function
-      // as both a named export and default export (e.g., `export const X` and `export default X`).
-      // Object.entries(mod) would return both entries pointing to the same function reference.
-      await import(plugin)
-        .then(async (mod) => {
-          const seen = new Set<PluginInstance>()
-          for (const [_name, fn] of Object.entries<PluginInstance>(mod)) {
-            if (seen.has(fn)) continue
-            seen.add(fn)
-            hooks.push(await fn(input))
+
+          // Subscribe to bus events, clean up when scope is closed
+          yield* Effect.acquireRelease(
+            Effect.sync(() =>
+              Bus.subscribeAll(async (input) => {
+                for (const hook of hooks) {
+                  hook["event"]?.({ event: input })
+                }
+              }),
+            ),
+            (unsub) => Effect.sync(unsub),
+          )
+
+          return { hooks }
+        }),
+      )
+
+      const trigger = Effect.fn("Plugin.trigger")(function* <
+        Name extends TriggerName,
+        Input = Parameters<Required<Hooks>[Name]>[0],
+        Output = Parameters<Required<Hooks>[Name]>[1],
+      >(name: Name, input: Input, output: Output) {
+        if (!name) return output
+        const state = yield* InstanceState.get(cache)
+        yield* Effect.promise(async () => {
+          for (const hook of state.hooks) {
+            const fn = hook[name] as any
+            if (!fn) continue
+            await fn(input, output)
           }
         })
-        .catch((err) => {
-          const message = err instanceof Error ? err.message : String(err)
-          log.error("failed to load plugin", { path: plugin, error: message })
-          Bus.publish(Session.Event.Error, {
-            error: new NamedError.Unknown({
-              message: `Failed to load plugin ${plugin}: ${message}`,
-            }).toObject(),
-          })
-        })
-    }
+        return output
+      })
+
+      const list = Effect.fn("Plugin.list")(function* () {
+        const state = yield* InstanceState.get(cache)
+        return state.hooks
+      })
 
-    return {
-      hooks,
-      input,
-    }
-  })
+      const init = Effect.fn("Plugin.init")(function* () {
+        yield* InstanceState.get(cache)
+      })
+
+      return Service.of({ trigger, list, init })
+    }),
+  )
+
+  const runPromise = makeRunPromise(Service, layer)
 
   export async function trigger<
-    Name extends Exclude<keyof Required<Hooks>, "auth" | "event" | "tool">,
+    Name extends TriggerName,
     Input = Parameters<Required<Hooks>[Name]>[0],
     Output = Parameters<Required<Hooks>[Name]>[1],
   >(name: Name, input: Input, output: Output): Promise<Output> {
-    if (!name) return output
-    for (const hook of await state().then((x) => x.hooks)) {
-      const fn = hook[name]
-      if (!fn) continue
-      // @ts-expect-error if you feel adventurous, please fix the typing, make sure to bump the try-counter if you
-      // give up.
-      // try-counter: 2
-      await fn(input, output)
-    }
-    return output
+    return runPromise((svc) => svc.trigger(name, input, output))
   }
 
-  export async function list() {
-    return state().then((x) => x.hooks)
+  export async function list(): Promise<Hooks[]> {
+    return runPromise((svc) => svc.list())
   }
 
   export async function init() {
-    const hooks = await state().then((x) => x.hooks)
-    const config = await Config.get()
-    for (const hook of hooks) {
-      // @ts-expect-error this is because we haven't moved plugin to sdk v2
-      await hook.config?.(config)
-    }
-    Bus.subscribeAll(async (input) => {
-      const hooks = await state().then((x) => x.hooks)
-      for (const hook of hooks) {
-        hook["event"]?.({
-          event: input,
-        })
-      }
-    })
+    return runPromise((svc) => svc.init())
   }
 }