Middleware not called for non-custom 404 page

[xriter]

What version of astro are you using?

2.9.6

Are you using an SSR adapter? If so, which one?

Node

What package manager are you using?

npm

What operating system are you using?

Mac

What browser are you using?

Safari

Describe the Bug

When you have middleware.ts setup, and a custom 404 page, the middleware will get called when you hit a 404 page. However, if you don't have a custom 404 page but rely on the default, the middleware won't get called.

Wondering if this is a deliberate decision?

What's the expected result?

Consistency between the custom and non-custom 404 page. Both should call the middleware.

Link to Minimal Reproducible Example

https://stackblitz.com/edit/github-pt4enm?file=src%2Fpages%2Findex.astro

Participation

• I am willing to submit a pull request for this issue.

[ematipico]

@xriter do you have this issue in development AND production?

[xriter]

@ematipico Yes, in both modes.

[lilnasy]

Even when 404.astro is added, middleware only runs in dev mode.

Repro: https://stackblitz.com/edit/github-pt4enm-xnujgy (added 404.astro and node adapter to the above repro)

Workaround: create a slug route and set Astro.response.status to 404.

Edit: this is a separate issue being tracked in #8154.

[ematipico]

I am going to close this issue as not planned.

This is the expected behaviour because we can't control default 404 pages, especially in adapters like Vercel, Netlify, etc.