fix(cli): argo lint with strict should report case-sensitive errors. Fixes #13006

[miltalex]

Fixes #13006

Motivation

Currently, when linting a CronWorkflow definition file, argo lint fails to detect keys with incorrect capitalization. This oversight can lead to unexpected behavior when applying these definitions using kubectl. Prior to this fix, argo cron create would ignore capitalization issues and proceed with the provided values, creating an inconsistency between kubectl and argo cron create behaviors.

By addressing this issue, we aim to:

1. Enhance the linting process to catch capitalization errors early in the development cycle.
2. Align the behavior of argo cron create/argo submit with kubectl, ensuring both tools report errors for incorrectly capitalized fields.
3. Streamline the workflow creation process by providing consistent feedback across different Argo and Kubernetes tools.

This change will help prevent potential errors by catching and reporting capitalization issues uniformly across all relevant tools.

Modifications

To address this issue, we've made the following change:

Modified the strict path of the linting process to utilize the sigs.k8s.io/json library for unmarshaling.

• This library provides case-sensitive unmarshaling in strict mode.
• Fields with incorrect capitalization (e.g., "schedUle" instead of "schedule") will now be unmarshaled as-is.
• The strict mode will then report these incorrectly capitalized fields as errors using the k8s.io/apimachinery/pkg/runtime library.

This change ensures that argo lint will now flag incorrectly capitalized fields when strict mode is enabled, providing developers with immediate feedback on potential issues in their workflow definitions. It also aligns the behavior of argo lint and argo cron create/argo submit with kubectl, creating a consistent experience across these tools.

Verification

To validate the effectiveness of this fix, I have extended the test suite with two new unit tests:

1. A test case for strict mode enabled, verifying that capitalization errors are correctly reported.
2. A test case for strict mode disabled, ensuring that the existing behavior remains unchanged.

[Joibel]

I am happy with this.

@agilgur5, I notice you were discussing making pkg do this strict check instead of doing it in here. That feels slightly better as an approach, but I don't want to block this on that. Would you rather we went that way?

[agilgur5]

@agilgur5, I notice you were discussing making pkg do this strict check instead of doing it in here. That feels slightly better as an approach, but I don't want to block this on that. Would you rather we went that way?

In #13006 (comment) I was primarily concerned about the scenario of "strict + case-sensitive". If the k8s variant handles this, then perhaps the functions in pkg are not even necessary and can be replaced and removed.

But if we wanted to, we could add this as an additional function in pkg and then load from the same place. For this case, I don't mind either way; would in fact prefer replacing and removing if possible.