From d2d5493136af4614798546c674d5707618429ca6 Mon Sep 17 00:00:00 2001
From: Neko Ayaka <neko@ayaka.moe>
Date: Sat, 18 Apr 2026 19:19:24 +0800
Subject: [PATCH] fix(stage-tamagotchi): concurrent apply and auto-heal will
 have conflicts

---
 .../main/libs/electron/persistence.test.ts    | 116 ++++++++++++++++++
 .../src/main/libs/electron/persistence.ts     |   3 +-
 2 files changed, 118 insertions(+), 1 deletion(-)
 create mode 100644 apps/stage-tamagotchi/src/main/libs/electron/persistence.test.ts

diff --git a/apps/stage-tamagotchi/src/main/libs/electron/persistence.test.ts b/apps/stage-tamagotchi/src/main/libs/electron/persistence.test.ts
new file mode 100644
index 000000000..2115de1ff
--- /dev/null
+++ b/apps/stage-tamagotchi/src/main/libs/electron/persistence.test.ts
@@ -0,0 +1,116 @@
+import { number, object } from 'valibot'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+/**
+ * @example
+ * describe('createConfig', () => {
+ *   it('persists configuration data', async () => {
+ *     // assertions
+ *   })
+ * })
+ */
+describe('createConfig', () => {
+  beforeEach(() => {
+    vi.resetModules()
+    vi.clearAllMocks()
+    vi.restoreAllMocks()
+  })
+
+  /**
+   * @example
+   * it('uses a unique temp file per save to avoid concurrent rename collisions', async () => {
+   *   await vi.waitFor(() => {
+   *     expect(renameMock).toHaveBeenCalledTimes(2)
+   *   })
+   * })
+   *
+   * Failed to save config Error: ENOENT: no such file or directory, rename '/path/to/the/electron/app/data/app-config.json.tmp' -> '/path/to/the/electron/app/data/app-config.json'
+   *   at async rename (node:internal/fs/promises:785:10)
+   *   at async file://./airi/apps/stage-tamagotchi/out/main/index.js:3327:4 {
+   *     errno: -2,
+   *     code: 'ENOENT',
+   *     syscall: 'rename',
+   *     path: '/path/to/the/electron/app/data/app-config.json.tmp',
+   *     dest: '/path/to/the/electron/app/data/app-config.json'
+   *   }
+   *
+   * ROOT CAUSE:
+   *
+   * If concurrent save calls share one temporary file path, one rename removes the file first.
+   * This causes a second rename attempt to fail with ENOENT, and the save path logs an error.
+   *
+   * We fixed this by asserting each save operation writes and renames a distinct temp file path.
+   */
+  it('uses a unique temp file per save to avoid concurrent rename collisions', async () => {
+    const appMock = {
+      getPath: vi.fn(() => '/tmp/airi-user-data'),
+    }
+    const mkdirMock = vi.fn(async () => {})
+    const existingTempFiles = new Set<string>()
+    const renameMock = vi.fn(async (from: string) => {
+      if (!existingTempFiles.has(from)) {
+        const error = new Error(`ENOENT: no such file or directory, rename '${from}'`) as NodeJS.ErrnoException
+        error.code = 'ENOENT'
+        throw error
+      }
+      existingTempFiles.delete(from)
+    })
+    const writeCoordinator = {
+      calls: 0,
+      waitFor: Promise.resolve(),
+      release: () => {},
+    }
+    const writeFileMock = vi.fn(async (path: string) => {
+      existingTempFiles.add(path)
+      writeCoordinator.calls += 1
+      if (writeCoordinator.calls === 2) {
+        writeCoordinator.release()
+      }
+      await writeCoordinator.waitFor
+    })
+
+    writeCoordinator.waitFor = new Promise<void>((resolve) => {
+      writeCoordinator.release = resolve
+    })
+
+    vi.doMock('electron', () => ({
+      app: appMock,
+    }))
+    vi.doMock('es-toolkit', () => ({
+      throttle: (handler: (...args: unknown[]) => unknown) => handler,
+    }))
+    vi.doMock('node:fs', () => ({
+      existsSync: () => false,
+      readFileSync: () => '',
+    }))
+    vi.doMock('node:fs/promises', () => ({
+      copyFile: vi.fn(async () => {}),
+      mkdir: mkdirMock,
+      rename: renameMock,
+      writeFile: writeFileMock,
+    }))
+
+    const { createConfig } = await import('./persistence')
+    const schema = object({ value: number() })
+    const config = createConfig('windows-widgets', 'config.json', schema, { default: { value: 0 } })
+    const saveErrorSpy = vi.spyOn(console, 'error').mockImplementation(() => {})
+
+    config.setup()
+    config.update({ value: 1 })
+    config.update({ value: 2 })
+
+    /**
+     * @example
+     * expect(renameMock).toHaveBeenCalledTimes(2)
+     * expect(saveErrorSpy).not.toHaveBeenCalledWith('Failed to save config', expect.anything())
+     * expect(new Set(renameMock.mock.calls.map(([from]) => from)).size).toBe(2)
+     */
+    await vi.waitFor(() => {
+      expect(renameMock).toHaveBeenCalledTimes(2)
+    })
+
+    expect(saveErrorSpy).not.toHaveBeenCalledWith('Failed to save config', expect.anything())
+    expect(new Set(renameMock.mock.calls.map(([from]) => from)).size).toBe(2)
+    saveErrorSpy.mockRestore()
+  })
+})
diff --git a/apps/stage-tamagotchi/src/main/libs/electron/persistence.ts b/apps/stage-tamagotchi/src/main/libs/electron/persistence.ts
index 5aa8229cf..7837f18c9 100644
--- a/apps/stage-tamagotchi/src/main/libs/electron/persistence.ts
+++ b/apps/stage-tamagotchi/src/main/libs/electron/persistence.ts
@@ -1,5 +1,6 @@
 import type { BaseIssue, BaseSchema, InferIssue, InferOutput } from 'valibot'
 
+import { randomUUID } from 'node:crypto'
 import { existsSync, readFileSync } from 'node:fs'
 import { copyFile, mkdir, rename, writeFile } from 'node:fs/promises'
 import { dirname, join } from 'node:path'
@@ -80,7 +81,7 @@ export function createConfig<TSchema extends PersistedSchema>(
     try {
       const path = configPath()
       await ensureConfigDirectory(path)
-      const tmpPath = `${path}.tmp`
+      const tmpPath = `${path}.${randomUUID()}.tmp`
       await writeFile(tmpPath, JSON.stringify(persistenceMap.get(key)))
       await rename(tmpPath, path)
     }