From d04eb854c6ed80ef68385409cddde9ae2a2d8c7f Mon Sep 17 00:00:00 2001
From: Dax Raad <d@ironbay.co>
Date: Sun, 10 May 2026 00:48:26 -0400
Subject: [PATCH] Add background code migration service

---
 packages/opencode/src/code-migration.ts | 77 +++++++++++++++++++++++++
 packages/opencode/src/index.ts          |  2 +
 2 files changed, 79 insertions(+)
 create mode 100644 packages/opencode/src/code-migration.ts

diff --git a/packages/opencode/src/code-migration.ts b/packages/opencode/src/code-migration.ts
new file mode 100644
index 0000000000..c03bd47605
--- /dev/null
+++ b/packages/opencode/src/code-migration.ts
@@ -0,0 +1,77 @@
+import { Context, Effect, Layer } from "effect"
+import { makeRuntime } from "./effect/run-service"
+import { Database, type TxOrDb } from "./storage/db"
+import { Global } from "@opencode-ai/core/global"
+import * as Log from "@opencode-ai/core/util/log"
+import path from "path"
+import { mkdir } from "fs/promises"
+
+export type Migration = {
+  name: string
+  run: (db: TxOrDb) => void | Promise<void>
+}
+
+export interface Interface {
+  readonly start: () => Effect.Effect<void>
+}
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/CodeMigration") {}
+
+const log = Log.create({ service: "code-migration" })
+const marker = path.join(Global.Path.data, "code-migration.json")
+
+export const All: Migration[] = []
+
+async function readCompleted() {
+  const file = Bun.file(marker)
+  if (!(await file.exists())) return new Set<string>()
+  return new Set((await file.json()) as string[])
+}
+
+async function writeCompleted(completed: Set<string>) {
+  await mkdir(path.dirname(marker), { recursive: true })
+  await Bun.write(marker, JSON.stringify([...completed].sort(), null, 2))
+}
+
+export const layer = Layer.effect(
+  Service,
+  Effect.gen(function* () {
+    let started = false
+
+    const start = Effect.fn("CodeMigration.start")(function* () {
+      if (started) return
+      started = true
+      yield* Effect.sync(() => {
+        void runPending().catch((error) => {
+          log.error("failed to run code migrations", { error })
+        })
+      })
+    })
+
+    return Service.of({ start })
+  }),
+)
+
+export const defaultLayer = layer
+
+async function runPending() {
+  if (All.length === 0) return
+
+  const db = Database.Client()
+
+  const completed = await readCompleted()
+  for (const migration of All.filter((item) => !completed.has(item.name))) {
+    log.info("running code migration", { name: migration.name })
+    await migration.run(db)
+    completed.add(migration.name)
+    await writeCompleted(completed)
+  }
+}
+
+const { runFork } = makeRuntime(Service, defaultLayer)
+
+export function start() {
+  runFork((svc) => svc.start())
+}
+
+export * as CodeMigration from "./code-migration"
diff --git a/packages/opencode/src/index.ts b/packages/opencode/src/index.ts
index 4c8e447041..40be1a7679 100644
--- a/packages/opencode/src/index.ts
+++ b/packages/opencode/src/index.ts
@@ -39,6 +39,7 @@ import { PluginCommand } from "./cli/cmd/plug"
 import { Heap } from "./cli/heap"
 import { drizzle } from "drizzle-orm/bun-sqlite"
 import { ensureProcessMetadata } from "@opencode-ai/core/util/opencode-process"
+import { CodeMigration } from "./code-migration"
 
 const processMetadata = ensureProcessMetadata("main")
 
@@ -151,6 +152,7 @@ const cli = yargs(args)
       }
       process.stderr.write("Database migration complete." + EOL)
     }
+    CodeMigration.start()
   })
   .usage("")
   .completion("completion", "generate shell completion script")