This problem happened before, and we solved it using treeKillSync.
Do you still have similar problems on you local machine?

Yes I do have the problem on the latest version (v0.28.7).

However, it works if I call treeKillSync in my own Vite config, or even just process.kill(process.electronApp.pid):

onstart({ startup }) {
	if (process.electronApp) {
		treeKillSync(process.electronApp.pid)
		// or
		process.kill(process.electronApp.pid)
	}
	startup()
},

It would be neat if it did a graceful shutdown with SIGTERM by waiting for the child_process to exit

@probablykasper Would you like to test the following changes locally?

function killTree(tree: PidTree) {
  if (tree.children) {
    for (const child of tree.children) {
      killTree(child)
    }
  }

  try {
-   process.kill(tree.pid) // #214
+   process.kill(tree.pid, 'SIGKILL') // Force kill process
  } catch { /* empty */ }
}

That does work. Personally I would prefer waiting for the child process to exit though instead of force quitting

Here's a working solution without force quitting:

startup.exit = async () => {
  if (process.electronApp) {
    process.electronApp.removeAllListeners();
    process.kill(process.electronApp.pid, 'SIGTERM');
    await new Promise((resolve) => {
      process.electronApp.once("exit", resolve);
    })
  }
};

Yes, it works for me. But I don't know how you want to incorporate treeKillSync

Maybe you could try this for me, it should work fine.
treeKillSync is required, we need to take care of people using Windows systems.

startup.exit = async () => {
  if (process.electronApp) {
    await new Promise((resolve) => {
      process.electronApp.removeAllListeners()
      process.electronApp.once('exit', resolve)
      treeKillSync(process.electronApp.pid!)
    })
  }
}

That does not work unfortunately. It doesn't quit, and gives me this error:

[47765:0919/044144.460406:ERROR:gpu_process_host.cc(993)] GPU process exited unexpectedly: exit_code=15
[47765:0919/044144.468629:ERROR:network_service_instance_impl.cc(601)] Network service crashed, restarting service.

The same error happened to me, but vite-plugin-electron still works fine. This error is thrown by Electron, it's not caused by us.

I am on macOS, yes. Are you testing with a before-quit handler like I use though?
https://github.com/probablykasper/ferrum/blob/7ac23dd2ca8fa397e51355aab6e0283f2e11be5a/src/electron/main.ts#L151-L168

I am on macOS, yes. Are you testing with a before-quit handler like I use though? https://github.com/probablykasper/ferrum/blob/7ac23dd2ca8fa397e51355aab6e0283f2e11be5a/src/electron/main.ts#L151-L168

This seems to be very tricky. treeKillSync(pid) directly kills the Renderer process(child process of Main process), causing the ipc handle you registered in before-quit to fail.
If we use process.kill(pid) instead of treeKillSync(pid), this will cause some Windows users to be unable to quit the previous App process instance.

The current known way is to circumvent this problem by customizing the startup.exit().

import electron, { startup } from 'vite-plugin-electron'

startup.exit = async () => {
  if (process.electronApp) {
    process.electronApp.removeAllListeners()
    process.kill(process.electronApp.pid)
  }
}

@probablykasper You can try this. This may seem like a complete hack. But it can at least help us circumvent the problem we are facing now.

import { resolve } from 'path'
import { defineConfig } from 'vite'
import { svelte, vitePreprocess } from '@sveltejs/vite-plugin-svelte'
import electron, { startup } from 'vite-plugin-electron'
import tailwindcss from '@tailwindcss/vite'

+ startup.exit = async () => {
+   if (process.electronApp) {
+     process.electronApp.removeAllListeners()
+     process.kill(process.electronApp.pid)
+   }
+ }

export default defineConfig({
  base: '/',
  clearScreen: false,
  resolve: {
    alias: {
      '@': resolve(__dirname, './src'),
    },
  },
  build: {
    outDir: './build/web',
    sourcemap: true,
    target: 'chrome106',
  },
  plugins: [
    svelte({
      preprocess: vitePreprocess(),
    }),
    tailwindcss(),
    electron({
      entry: ['./src/electron/main.ts', './src/electron/preload.ts'],
-     onstart({ startup }) {
-       if (process.electronApp) {
-         process.kill(process.electronApp.pid, 'SIGTERM')
-       } else {
-         startup()
-       }
-     },
      vite: {
        build: {
          outDir: './build/electron',
          emptyOutDir: true,
          rollupOptions: {
            external: [/^.*\.node$/],
          },
        },
      },
    }),
  ],
})

If we use process.kill(pid) instead of treeKillSync(pid), this will cause some Windows users to be unable to quit the previous App process instance.

Do Wondows users have that issue even with the .once('exit', resolve)? Could be worth testing.

Seems weird if the tree-kill is the only way to quit the app 🤔

Do Wondows users have that issue even with the .once('exit', resolve)? Could be worth testing.

Seems weird if the tree-kill is the only way to quit the app 🤔

I created a v0.28.9 branch which may fix this issue.
Would you like to build the v0.28.9 branch locally and test if it works?

I tried your example and it works fine on v0.28.9 branch.

It does not work unfortunately. I made a reproduction repo here: https://github.com/probablykasper/vite-plugin-electron-bug

It does not work unfortunately. I made a reproduction repo here: https://github.com/probablykasper/vite-plugin-electron-bug

Private repo?

So sorry, public now

I write a module to terminate Electron zombie processes, which has been successfully used in my project for a long time. It has only been tested on Windows.

import electron from 'vite-plugin-electron/simple';
import { killElectron } from 'kill-electron';

export default defineConfig({
  plugins: [
    electron({
      onstart: args => {
        if (os.platform() === 'win32') {
          spawn('chcp', ['65001']);
        }
      
        if (process.env.VSCODE_DEBUG) {
          console.log(
            /* For `.vscode/.debug.script.mjs` */ '[startup] Electron App'
          );
        } else {
          void args.startup();
        }
        // Orphaned Electron processes can occur during debugging
        // To prevent system slowdowns, these processes need to be killed before each startup
        killElectron({
          zombieOnly: true
        });
      },
// ... rest code of vite config

vite-plugin-electron v0.28.8
vite v5.3.1

In mac, when I make modifications in the main process main.js, the BrowserWindow instance of electron will be re-created,
What should I do?

export default defineConfig({
  plugins: [
    vue(),
    vueJsx(),
    vueDevTools(),
    electron([
      {
        entry: "electron/main.js",
      },
      {
        entry: "electron/preload.js",
      },
    ]),
    electronRenderer(),
  ],
})

also present when stopped and are more instances which uses the same dev port...

Some of this https://github.com/vite-plugin repos may solve multiple instances or dev instances, but when there are multiple clients and users of Electron apps on Desktop, then this issue become something more when ports could be assigned for same port in different frameworks or different plugins or something different than Electron...