Return a more specific http status code on conflict.

[jmcarp]

Just a nit I noticed while working on something else. Semantically, ObjectAlreadyExists maps to an http 409 and not a 400.

[david-crespo]

This is going to break a whole lot of tests.

[sudomateo]

Usually, generic HTTP status codes are used as a security measure to prevent clients from enumerating information about API objects. Since we already return ObjectAlreadyExists text perhaps that's a moot point and this change makes sense as-is.

[davepacheco]

Reference: https://github.com/oxidecomputer/omicron/blob/main/docs/http-status-codes.adoc#client-errors

This is changeable but it does seem like a breaking API change.

[jmcarp]

This is going to break a whole lot of tests.

Yes, but mostly the kind of test that Claude can fix.

Since we already return ObjectAlreadyExists text perhaps that's a moot point and this change makes sense as-is.

I think that's right. I don't think the choice of the generic 400 over a 409 here was related to obfuscation, because creating a resource would be behind auth, so a malicious user would hit a 401 or 403 before being able to enumerate resources.

This is changeable but it does seem like a breaking API change.

Yes, it's possible that customers are depending on receiving a 400, although I'm not sure how likely that is.

How disruptive would this change be? All things being equal, I think it would be nice to use more specific http status codes, but if it would be annoying to us or users, I'll just close this.

[david-crespo]

Honestly not sure. I agree 409 is more correct, but the improvement is small enough that it would only have to be a tiny bit inconvenient to not be worth it. There are a couple of spots in the console where we look at the status code, but I think we only rely on it for 404 and 403, not for 400, precisely because the latter is so general that the error code is always more informative.

https://github.com/oxidecomputer/console/blob/8e240f115e03cecc0d0f32e9fc9a73ee739125e3/app/components/ErrorBoundary.tsx?plain=1#L64-L68