fix(opencode): serialize config bun installs (#17342)

2 files changed, 37 insertions, 1 deletions

diff --git a/packages/opencode/src/config/config.ts b/packages/opencode/src/config/config.ts
index f3d0d0b7a..27ba4e186 100644
--- a/packages/opencode/src/config/config.ts
+++ b/packages/opencode/src/config/config.ts
@@ -37,6 +37,7 @@ import { Account } from "@/account"
 import { ConfigPaths } from "./paths"
 import { Filesystem } from "@/util/filesystem"
 import { Process } from "@/util/process"
+import { Lock } from "@/util/lock"
 
 export namespace Config {
   const ModelId = z.string().meta({ $ref: "https://models.dev/model-schema.json#/$defs/Model" })
@@ -289,6 +290,7 @@ export namespace Config {
 
     // Install any additional dependencies defined in the package.json
     // This allows local plugins and custom tools to use external packages
+    using _ = await Lock.write("bun-install")
     await BunProc.run(
       [
         "install",
diff --git a/packages/opencode/test/config/config.test.ts b/packages/opencode/test/config/config.test.ts
index 90727cf8a..baf209d86 100644
--- a/packages/opencode/test/config/config.test.ts
+++ b/packages/opencode/test/config/config.test.ts
@@ -1,4 +1,4 @@
-import { test, expect, describe, mock, afterEach } from "bun:test"
+import { test, expect, describe, mock, afterEach, spyOn } from "bun:test"
 import { Config } from "../../src/config/config"
 import { Instance } from "../../src/project/instance"
 import { Auth } from "../../src/auth"
@@ -10,6 +10,7 @@ import { pathToFileURL } from "url"
 import { Global } from "../../src/global"
 import { ProjectID } from "../../src/project/schema"
 import { Filesystem } from "../../src/util/filesystem"
+import { BunProc } from "../../src/bun"
 
 // Get managed config directory from environment (set in preload.ts)
 const managedConfigDir = process.env.OPENCODE_TEST_MANAGED_CONFIG_DIR!
@@ -763,6 +764,39 @@ test("installs dependencies in writable OPENCODE_CONFIG_DIR", async () => {
   }
 })
 
+test("serializes concurrent config dependency installs", async () => {
+  await using tmp = await tmpdir()
+  const dirs = [path.join(tmp.path, "a"), path.join(tmp.path, "b")]
+  await Promise.all(dirs.map((dir) => fs.mkdir(dir, { recursive: true })))
+
+  const seen: string[] = []
+  let active = 0
+  let max = 0
+  const run = spyOn(BunProc, "run").mockImplementation(async (_cmd, opts) => {
+    active++
+    max = Math.max(max, active)
+    seen.push(opts?.cwd ?? "")
+    await new Promise((resolve) => setTimeout(resolve, 25))
+    active--
+    return {
+      code: 0,
+      stdout: Buffer.alloc(0),
+      stderr: Buffer.alloc(0),
+    }
+  })
+
+  try {
+    await Promise.all(dirs.map((dir) => Config.installDependencies(dir)))
+  } finally {
+    run.mockRestore()
+  }
+
+  expect(max).toBe(1)
+  expect(seen.toSorted()).toEqual(dirs.toSorted())
+  expect(await Filesystem.exists(path.join(dirs[0], "package.json"))).toBe(true)
+  expect(await Filesystem.exists(path.join(dirs[1], "package.json"))).toBe(true)
+})
+
 test("resolves scoped npm plugins in config", async () => {
   await using tmp = await tmpdir({
     init: async (dir) => {