`wrangler types` causes `Assertion failed: !(handle->flags & UV_HANDLE_CLOSING), file src\win\async.c, line 76`

[Atulin]

What versions & operating system are you using?

❯ bunx envinfo --system --npmPackages '{wrangler,create-cloudflare,miniflare,@cloudflare/*}' --binaries

  System:
    OS: Windows 11 10.0.26200
    CPU: (24) x64 AMD Ryzen 9 9900X 12-Core Processor
    Memory: 28.21 GB / 61.61 GB
  Binaries:
    Node: 24.15.0 - C:\Users\[username]\AppData\Local\fnm_multishells\59556_1777501796804\node.EXE
    npm: 11.12.1 - C:\Users\[username]\AppData\Local\fnm_multishells\59556_1777501796804\npm.CMD
    bun: 1.3.13 - C:\Users\[username]\.bun\bin\bun.EXE
    Deno: 2.7.14 - C:\Users\[username]\AppData\Local\Microsoft\WinGet\Links\deno.EXE
  npmPackages:
    @cloudflare/vitest-pool-workers: ^0.12.4 => 0.12.21
    wrangler: ^4.86.0 => 4.86.0

Please provide a link to a minimal reproduction

It happens on wrangler init, not really any repro

Describe the Bug

❯ wrangler types

 ⛅️ wrangler 4.86.0
───────────────────
Generating project types...

declare namespace Cloudflare {
        interface GlobalProps {
                mainModule: typeof import("./src/index");
        }
        interface Env {
        }
}
interface Env extends Cloudflare.Env {}

Generating runtime types...


▲ [WARNING] A fetch request failed, likely due to a connectivity issue.


  Common causes:
    - No internet connection or network connectivity problems
    - Firewall or VPN blocking the request
    - Network proxy configuration issues

  Please check your network connection and try again.


✘ [ERROR] fetch failed


If you think this is a bug then please create an issue at https://github.com/cloudflare/workers-sdk/issues/new/choose
🪵  Logs were written to "C:\Users\[username][\AppData\Roaming\xdg.config\.wrangler\logs\wrangler-2026-04-29_22-48-28_653.log"
Assertion failed: !(handle->flags & UV_HANDLE_CLOSING), file src\win\async.c, line 76

Please provide any relevant error logs

Details

--- 2026-04-29T22:48:28.767Z debug
🪵  Writing logs to "C:\Users\[username]\AppData\Roaming\xdg.config\.wrangler\logs\wrangler-2026-04-29_22-48-28_653.log"
---

--- 2026-04-29T22:48:28.767Z debug
.env file not found at "F:\[project]\.env". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2026-04-29T22:48:28.767Z debug
.env file not found at "F:\[project]\.env.local". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2026-04-29T22:48:28.772Z log

 ⛅️ wrangler 4.86.0
───────────────────
---

--- 2026-04-29T22:48:28.774Z debug
Metrics dispatcher: Posting data {"deviceId":"a2d2a25d-e03a-4450-85f2-b3252c2fd5ca","event":"wrangler command started","timestamp":1777502908774,"properties":{"amplitude_session_id":1777502908773,"amplitude_event_id":0,"wranglerVersion":"4.86.0","wranglerMajorVersion":4,"wranglerMinorVersion":86,"wranglerPatchVersion":0,"osPlatform":"Windows","osVersion":"Windows 11 Home","nodeVersion":24,"isFirstUsage":false,"configFileType":"none","isCI":false,"isPagesCI":false,"isWorkersCI":false,"isInteractive":true,"hasAssets":false,"agent":null,"argsUsed":[],"argsCombination":"","sanitizedCommand":"types","sanitizedArgs":{}}}
---

--- 2026-04-29T22:48:28.872Z log
Generating project types...

---

--- 2026-04-29T22:48:28.873Z debug
local dev variables file not found at ".dev.vars". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2026-04-29T22:48:28.873Z debug
.env file not found at "F:\[project]\.env". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2026-04-29T22:48:28.873Z debug
.env file not found at "F:\[project]\.env.local". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2026-04-29T22:48:28.876Z log
declare namespace Cloudflare {
	interface GlobalProps {
		mainModule: typeof import("./src/index");
	}
	interface Env {
	}
}
interface Env extends Cloudflare.Env {}

---

--- 2026-04-29T22:48:28.876Z log
Generating runtime types...

---

--- 2026-04-29T22:48:30.127Z debug
Metrics dispatcher: Posting data {"deviceId":"a2d2a25d-e03a-4450-85f2-b3252c2fd5ca","event":"wrangler command errored","timestamp":1777502910127,"properties":{"amplitude_session_id":1777502908773,"amplitude_event_id":1,"wranglerVersion":"4.86.0","wranglerMajorVersion":4,"wranglerMinorVersion":86,"wranglerPatchVersion":0,"osPlatform":"Windows","osVersion":"Windows 11 Home","nodeVersion":24,"isFirstUsage":false,"configFileType":"none","isCI":false,"isPagesCI":false,"isWorkersCI":false,"isInteractive":true,"hasAssets":false,"agent":null,"argsUsed":[],"argsCombination":"","sanitizedCommand":"types","sanitizedArgs":{},"durationMs":1358,"errorType":"TypeError"}}
---

--- 2026-04-29T22:48:30.128Z log

---

--- 2026-04-29T22:48:30.221Z warn
▲ [WARNING] A fetch request failed, likely due to a connectivity issue.

  
  Common causes:
    - No internet connection or network connectivity problems
    - Firewall or VPN blocking the request
    - Network proxy configuration issues
  
  Please check your network connection and try again.


---

--- 2026-04-29T22:48:30.222Z error
✘ [ERROR] fetch failed


---

--- 2026-04-29T22:48:30.222Z debug
TypeError: fetch failed
    at Object.processResponse (C:\Users\[username]\.bun\install\global\node_modules\undici\lib\web\fetch\index.js:237:16)
    at C:\Users\[username]\.bun\install\global\node_modules\undici\lib\web\fetch\index.js:1081:19
    at node:internal/process/task_queues:150:7
    at AsyncResource.runInAsyncScope (node:async_hooks:227:14)
    at AsyncResource.runMicrotask (node:internal/process/task_queues:147:8)
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at C:\Users\[username]\.bun\install\global\node_modules\undici\index.js:157:7
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async fetch5 (C:\Users\[username]\.bun\install\global\node_modules\miniflare\dist\src\index.js:58932:20)
    at async _Miniflare.dispatchFetch (C:\Users\[username]\.bun\install\global\node_modules\miniflare\dist\src\index.js:89089:22)
    at async generate (C:\Users\[username]\.bun\install\global\node_modules\wrangler\wrangler-dist\cli.js:296222:17)
    at async generateRuntimeTypes (C:\Users\[username]\.bun\install\global\node_modules\wrangler\wrangler-dist\cli.js:296199:19)
    at async Object.handler (C:\Users\[username]\.bun\install\global\node_modules\wrangler\wrangler-dist\cli.js:299072:51)
    at async C:\Users\[username]\.bun\install\global\node_modules\wrangler\wrangler-dist\cli.js:183853:26
    at async Object.handler (C:\Users\[username]\.bun\install\global\node_modules\wrangler\wrangler-dist\cli.js:183802:7)
---

--- 2026-04-29T22:48:30.222Z log
If you think this is a bug then please create an issue at https://github.com/cloudflare/workers-sdk/issues/new/choose
---

[edmundhung]

Hi @Atulin,

Since Bun is mentioned in the report, could you try these and share the results? Please also include the debug logs from those runs.

• npx wrangler@4.86.0 types
• npx wrangler@4.86.0 types --include-runtime=false
• npx wrangler@4.86.0 dev

A minimal repro would help us narrow this down. It would also help to know the last Wrangler version that worked for you. Thanks!

[Atulin]

❯ npx wrangler@4.86.0 types

 ⛅️ wrangler 4.86.0 (update available 4.87.0)
─────────────────────────────────────────────
Generating project types...

declare namespace Cloudflare {
	interface GlobalProps {
		mainModule: typeof import("./src/index");
	}
	interface Env {
	}
}
interface Env extends Cloudflare.Env {}

Generating runtime types...


▲ [WARNING] A fetch request failed, likely due to a connectivity issue.


  Common causes:
    - No internet connection or network connectivity problems
    - Firewall or VPN blocking the request
    - Network proxy configuration issues

  Please check your network connection and try again.


X [ERROR] fetch failed


If you think this is a bug then please create an issue at https://github.com/cloudflare/workers-sdk/issues/new/choose
Note that there is a newer version of Wrangler available (4.87.0). Consider checking whether upgrading resolves this error.
🪵  Logs were written to "C:\Users\[username]\AppData\Roaming\xdg.config\.wrangler\logs\wrangler-2026-05-05_14-33-21_832.log"
Assertion failed: !(handle->flags & UV_HANDLE_CLOSING), file src\win\async.c, line 76

wrangler-2026-05-05_14-33-21_832.log

❯ npx wrangler@4.86.0 types --include-runtime=false

 ⛅️ wrangler 4.86.0 (update available 4.87.0)
─────────────────────────────────────────────
Generating project types...

declare namespace Cloudflare {
	interface GlobalProps {
		mainModule: typeof import("./src/index");
	}
	interface Env {
	}
}
interface Env extends Cloudflare.Env {}

────────────────────────────────────────────────────────────
✨ Types written to worker-configuration.d.ts

📣 Remember to rerun 'wrangler types' after you change your wrangler.toml file.

wrangler-2026-05-05_14-33-50_998.log

❯ npx wrangler@4.86.0 dev

 ⛅️ wrangler 4.86.0 (update available 4.87.0)
─────────────────────────────────────────────
╭──────────────────────────────────────────────────────────────────────────────────────────────╮
│  [b] open a browser [d] open devtools [e] open local explorer [c] clear console [x] to exit  │
╰──────────────────────────────────────────────────────────────────────────────────────────────╯
⎔ Starting local server...
[wrangler:info] Ready on http://127.0.0.1:8787
⎔ Shutting down local server...

And gets stuck at this point after pressing X, doesn't react to Ctrl+C, the terminal needs to be killed.

wrangler-2026-05-05_14-35-13_832.log