fix: Bun build failes in docker with "Export 'toNodeHandler' not found" when using Nuxt Devtools alpha.9 and @nuxt/image and special tsconfig

リンクされている NuxtDevToolsMinimal の再現環境をクローンし、docker build --no-cache . を実行して bun run build での失敗を確認します。記載されている @nuxt/devtools のバージョンを比較し、package.json、nuxt.config.ts、レガシーな tsconfig.json、Dockerfile、postinstall の設定を調査します。toNodeHandler の export エラーなしで Docker ビルドが完了すれば完了です。

🐛 The bug

Bug/Error:
I found a very specific interaction bug in @nuxt/devtools Version 4.0.0-alpha.8 and 4.0.0-alpha.9 (it doesn't happen in 4.0.0-alpha.7). This is quite an edge case.

The docker build fails at bun run build with the error:

ERROR  Export named 'toNodeHandler' not found in module '/app/node_modules/h3/dist/index.cjs'.
     at <parse> (:0)
     at processTicksAndRejections (native:7:39)

error: script "build" exited with code 1

🛠️ To reproduce

https://github.com/DragonFire7/NuxtDevToolsMinimal

🌈 Expected behavior

Minimal reproduction:
I built a minimal reproduction here: https://github.com/DragonFire7/NuxtDevToolsMinimal

1. Clone the repository.
2. Run docker build --no-cache .
3. The build crashes at the bun run build step.

Expected bahavior:
No errors when running the docker build

ℹ️ Additional context

Description/Details:
The bug happens when building with Docker and Bun. It does not happen locally on my Windows machine.

It only occurs when all of the following criteria are met:

• package.json: @nuxt/image and @nuxt/devtools (with one of the mentioned versions) are in the devDependencies. The build and postinstall scripts must also be present.
• nuxt.config.ts: A basic config utilizing the Nitro preset for Bun.
• tsconfig.json: This is why I call it an edge case. It only happens when the project came from Nuxt 3 and still uses the legacy Nuxt 3 tsconfig format. When updating my project's config to the new Nuxt 4 tsconfig format, everything works perfectly again.
• Dockerfile: The Dockerfile is pretty standard and only shows the building stage, since the error already occurs there.

What I found through trial and error:

• Without the postinstall script, the types don't seem to be generated while building, thus the tsconfig.json doesn't have any effect and the build succeeds.
• Without @nuxt/image, no error occurs. The issue seems to be introduced by an interaction between the two modules during the build process.
• Switching the base image from oven/bun:1-alpine to oven/bun:1-slim or oven/bun:1 didn't have any effect.

Since this is very much an edge case tied to an outdated tsconfig.json, it is low priority in my opinion. However, I wanted to report it in case it helps others searching for a solution