fix(cli): elect one service process

packages/cli/test/service.test.ts

@@ -1,7 +1,8 @@
 import { NodeFileSystem } from "@effect/platform-node"
+import { Service } from "@opencode-ai/client/effect"
 import { Global } from "@opencode-ai/core/global"
 import { expect, test } from "bun:test"
-import { Effect } from "effect"
+import { Effect, Schema } from "effect"
 import fs from "node:fs/promises"
 import os from "node:os"
 import path from "node:path"
@@ -24,3 +25,47 @@ test("local channel stores service config with the local service filename", asyn
     await fs.rm(root, { recursive: true, force: true })
   }
 })
+
+test("concurrent service processes elect one server", async () => {
+  const root = await fs.mkdtemp(path.join(os.tmpdir(), "opencode-service-election-"))
+  const env = {
+    ...process.env,
+    HOME: root,
+    OPENCODE_DB: path.join(root, "opencode.db"),
+    OPENCODE_TEST_HOME: root,
+    XDG_CACHE_HOME: path.join(root, "cache"),
+    XDG_CONFIG_HOME: path.join(root, "config"),
+    XDG_DATA_HOME: path.join(root, "data"),
+    XDG_STATE_HOME: path.join(root, "state"),
+  }
+  const command = [process.execPath, path.join(import.meta.dir, "../src/index.ts"), "serve", "--service"]
+  const first = Bun.spawn(command, { env, stderr: "pipe", stdout: "ignore" })
+  const second = Bun.spawn(command, { env, stderr: "pipe", stdout: "ignore" })
+
+  try {
+    const registration = path.join(root, "state", "opencode", "service-local.json")
+    const info = await waitForInfo(registration)
+    const winner = info.pid === first.pid ? first : second
+    const loser = info.pid === first.pid ? second : first
+    const exited = await Promise.race([loser.exited.then(() => true), Bun.sleep(10_000).then(() => false)])
+
+    expect(exited).toBe(true)
+    expect(winner.exitCode).toBe(null)
+  } finally {
+    first.kill("SIGTERM")
+    second.kill("SIGTERM")
+    await Promise.all([first.exited, second.exited])
+    await fs.rm(root, { recursive: true, force: true })
+  }
+})
+
+async function waitForInfo(file: string) {
+  for (let attempt = 0; attempt < 200; attempt++) {
+    const value = await Bun.file(file)
+      .json()
+      .catch(() => undefined)
+    if (value !== undefined) return Schema.decodeUnknownPromise(Service.Info)(value)
+    await Bun.sleep(50)
+  }
+  throw new Error("Timed out waiting for service registration")
+}