kustomize build fails silently when first line is invalid yaml

[gilbahat]

when encountering a malformed kustomization.yaml file which is due to poor definition, kustomize will silently create an empty yaml file instead of reporting an error:

(note the two spaces at the beginning of the yaml file!)

✗ head infrastructure/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
(... snipped ...)

✗ kustomize build infrastructure -o test.yaml
✗ ls -l test.yaml
-rw-r--r-- 1 gilbahat staff 0 Nov 10 14:06 test.yaml

this is unlike other error modes which output usable error messages and do not generate an empty yaml file, e.g.:

✗ kustomize build infrastructure -o test.yaml
Error: accumulating resources: accumulation err='accumulating resources from (... snipped ...)
✗ ls -l test.yaml
ls: test.yaml: No such file or directory

[KnVerey]

/retitle kustomize build fails silently when first line is invalid yaml

Reproduced with:

 apiVersion: kustomize.config.k8s.io/v1beta1 # first character is a space
kind: Kustomization
resources:
- resources.yaml # contains a simple configmap

Neither output nor an error is produced.

/triage accepted

[natasha41575]

@koba1t do you have time to take a look at this issue?

[koba1t]

I'll check it.

/assign koba1t

[koba1t]

I think it is caused by yaml library.
https://go.dev/play/p/euY_dbzbqwe

[KnVerey]

Good instinct to try reproducing with upstream yaml! If I understand correctly, the hypothesis is that we successfully read in apiVersion: kustomize.config.k8s.io/v1beta1 and then the rest of the file gets discarded? I'm wondering if there's anything else Kustomize could do here, maybe along the lines of throwing an error if the Kustomization loaded is empty? Currently, running kustomize build against a blank file that has the right filename exits without an error as well.

/area yaml-upstream

[koba1t]

maybe along the lines of throwing an error if the Kustomization loaded is empty?

That is a very good idea rather than fixing the upstream YAML library!
I'll try it!