"field not allowed" error when embedding a definition inside an if comprehension

[coding-yogi]

What version of CUE are you using (cue version)?

$ cue version
v0.10.0

Does this issue reproduce with the latest stable release?

Yes

What did you do?

Trying to eval below cue config

#cluster: {
    karpenter: {
      enable: bool | *true
    }
}

_cluster: #cluster

#service_account_annotations: {
  [Name=string]: {
    service_account: {
      annotations: {
        "test": "test"
      }
    }
  }
}

if _cluster.karpenter.enable {
  #service_account_annotations:karpenter: {}

  karpenter: {
    replicas: int | *2
    #service_account_annotations.karpenter
  }
}

What did you expect to see?

I except the if condition to evaluate and generate the required karpenter struct, but it fails. If the if statement is commented, then code works fine.

I understand that #service_account_annotations:karpenter: {} is a closed struct , and making it open works.
But I am not sure why it complains about the fields of karpenter

What did you see instead?

karpenter.replicas: field not allowed:

[mvdan]

Nicely spotted, this appears to be a bug in both the old and new evaluator. Simplified below:

env CUE_EXPERIMENT=evalv3=0
exec cue export input.cue

env CUE_EXPERIMENT=evalv3=1
exec cue export input.cue

-- input.cue --
#schema: {}

if true {
	out: {
		#schema
		extra: "foo"
	}
}

Which results in the following testscript output:

> env CUE_EXPERIMENT=evalv3=0
> exec cue export input.cue
[stderr]
out.extra: field not allowed:
    ./input.cue:1:10
    ./input.cue:3:1
    ./input.cue:5:3
    ./input.cue:6:3
[exit status 1]
FAIL: test.cue:2: unexpected command failure
> env CUE_EXPERIMENT=evalv3=1
> exec cue export input.cue
[stderr]
out.extra: field not allowed:
    ./input.cue:6:10
    ./input.cue:6:3
[exit status 1]
FAIL: test.cue:5: unexpected command failure
failed run

I know this is a bug because removing the if true conditional results in JSON output. This bug seems to be pretty similar to #3483, except that it affects the old evaluator too.

[mvdan]

Note that the commit above only fixes the issue for the new evaluator, enabled via CUE_EXPERIMENT=evalv3.