struct-tag rule false-positive on json inline tag

[finnan444]

Describe the bug
struct-tag produces warning for json inline tag struct-tag: unknown option 'inline' in JSON tag (revive)

To Reproduce
Steps to reproduce the behavior:

1. add

type Beta struct {
    Alpha `json:",inline"`
}

2. Run revive with struct-tag rule enabled

[chavacava]

Hi @finnan444 thanks for filling the issue.
In fact inline is not an official option of JSON struct tags (this 8 years old but still ongoing discussion also talks about it)

(Actually, the inline option works by lucky it might be possible that if you change yours inline by something it will still working)

[finnan444]

Hi @chavacava, sorry for inconvenience, this tag is widely used in my company (this practice came from kubernetes repo), so i thought inline is part of standard now.
I suppose issue can be closed

[chavacava]

Do not worry, we have been all trapped by this inline option :)

Thanks again for taking the time of filling the issue.

[s3rj1k]

@chavacava So why not add a configuration option to struct-tag linter?

[chavacava]

@s3rj1k What do you need to configure?

[s3rj1k]

I was thinking of an array with additionally allowed list of tags, to make that inline tag allowed per user-configuration
(or any other none standard tag)

[chavacava]

Could you please develop on the interest of using non-standard options in struct tags?
Why not just remove inline from JSON tags? (unknown options are ignored by encoding/json)

[s3rj1k]

@chavacava inline tag is needed for kubernetes CRD creation, please see link below
https://book.kubebuilder.io/reference/generating-crd.html#additional-printer-columns

[chavacava]

I do not know about CRD creation but I know that non standard tag options are ignored by encoding\json so its hard to me to imagine what is the interest of using inline option.
Did you try to replace json:",inline" by just json:"" when creating a CRD? It should be semantically equivalent as this code shows

I was thinking of an array with additionally allowed list of tags, to make that inline tag allowed per user-configuration

If we add a configuration, it should allow additional options but scoped to particular tags. For example, by allowing inline for JSON tags does not allow it for other tags (ASN, csv, base64, ...)

[s3rj1k]

@chavacava inline is used across all K8s code, for example here https://github.com/kubernetes/kubernetes/blob/master/pkg/controller/garbagecollector/metaonly/types.go#L30

I would rather use it also like docs say.

If we add a configuration, it should allow additional options but scoped to particular tags. For example, by allowing inline for JSON tags does not allow it for other tags (ASN, csv, base64, ...)

Sure, so a list per tag or a map[string][]string

[chavacava]

inline is used across all K8s code

I know. I use Kubernetes repo as the main sandbox for testing new linting rules because: a) it is a huge repo and, b) it is not famous for its coding style quality ;)

[s3rj1k]

So, either we have some kind of a configurable option for struct-tag, to allow this K8s mess and have other struct tags checked or we go and disable struct-tag linter for specific places or for all code base.

Personally I would be happy with configuration option, that way linter will work on other structs inside project.

[s3rj1k]

@chavacava Bump, I am forced to use exclude rule for this and this is ugly.

[chavacava]

@s3rj1k I've made the PR #802 to let users tag structs with all the unofficial options they can imagine.