API server should return 4xx for invalid path in JSON Patch, not 500 Internal Server Error

[felixfbecker]

Is this a BUG REPORT or FEATURE REQUEST?:

Uncomment only one, leave it on its own line:

/kind bug

What happened:
If you make an RFC6902 JSON Patch request to the server that contains an operation with an invalid path, the server returns 500 Internal Server Error with response

{
    "kind": "Status",
    "apiVersion": "v1",
    "metadata": {},
    "status": "Failure",
    "message": "jsonpatch add operation does not apply: doc is missing path: invalid",
    "code": 500
}

What you expected to happen:

400 Bad Request seems the most appropiate here:

Malformed patch document: When the server determines that the patch
document provided by the client is not properly formatted, it
SHOULD return a 400 (Bad Request) response. The definition of
badly formatted depends on the patch document chosen.

https://tools.ietf.org/html/rfc5789#section-2.2

How to reproduce it (as minimally and precisely as possible):
PATCH a deployment with ContentType: application/json-patch+json and body

[{"op": "add", "value": 123, "path": "invalid"}]

Anything else we need to know?:

Related #68202, #54423

Environment:

• Kubernetes version (use kubectl version): v1.10.3
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release): macOS
• Kernel (e.g. uname -a):
• Install tools:
• Others:

[felixfbecker]

@kubernetes/sig-api-machinery-bugs

[k8s-ci-robot]

@felixfbecker: Reiterating the mentions to trigger a notification:
@kubernetes/sig-api-machinery-bugs

In response to this:

@kubernetes/sig-api-machinery-bugs

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[fedebongio]

/assign @jennybuckley

[fejta-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/lifecycle stale

[fejta-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/lifecycle rotten

[jennybuckley]

/remove-lifecycle rotten

[jennybuckley]

Is this fixed by #68346?

[fejta-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/lifecycle stale

[fejta-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/lifecycle rotten

[fejta-bot]

Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh with /remove-lifecycle rotten.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/close

[k8s-ci-robot]

@fejta-bot: Closing this issue.

In response to this:

Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh with /remove-lifecycle rotten.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.