fix: avoid verify empty container cmd/args

[reingart]

Description

In verify job stanzas, do not copy container commands or arguments if not specified in skaffold.yaml

If not, original command/argument defined in the job will be overwritten with nil.

Previous "bogus" behavior could be reproduced using empty string command or args, for example:

verify:
- name: test-happy-path
  container:
    name: test
    image: test
    args: []
  executionMode:
    kubernetesCluster:
      jobManifestPath: tests/job.yml

UT comming soon

[gemini-code-assist]

Summary of Changes

Hello @reingart, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical bug in Skaffold's verify functionality that could lead to unexpected behavior in Kubernetes jobs. Previously, if container commands or arguments were omitted from the skaffold.yaml configuration for a verify step, they would inadvertently clear out any pre-defined commands or arguments in the underlying Kubernetes job manifest. The fix introduces conditional logic to prevent this overwriting, ensuring that only explicitly provided values are applied. Additionally, the change enhances the observability of the verification process by integrating more detailed debug and trace logging.

Highlights

• Bug Fix: Container Command/Args Overwrite: Resolved an issue where verify jobs would incorrectly overwrite existing container commands or arguments in Kubernetes job manifests with nil if they were not explicitly defined in the skaffold.yaml.
• Conditional Patching Logic: The patchToK8sContainer function now conditionally applies Command and Args to a Kubernetes container only if these fields are present in the Skaffold configuration, preventing unintended clearing of values.
• Enhanced Debug Logging: Added several debug and trace log statements to provide better visibility into the lifecycle of verify jobs, including creation, pod status (succeeded/failed), cleanup, and container patching details.

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[gemini-code-assist]

Code Review

This pull request correctly addresses an issue where container command and args from a job manifest were being overwritten. The conditional logic in patchToK8sContainer is a good fix. The addition of extensive debug and trace logging is also a welcome improvement for maintainability. I have a few suggestions to refine the implementation. The primary concern is ensuring the fix fully covers the scenario described in the PR (using an empty slice []). Additionally, the new logging statements should consistently use the available function context instead of context.TODO() to preserve trace information and enable proper cancellation.

[gemini-code-assist]

This fix correctly prevents overwriting the command/args when they are not specified in the skaffold.yaml. However, the PR description mentions that the 'bogus' behavior can be reproduced with args: []. With the current check (container.Args != nil), an empty slice [] is not nil, so it would still overwrite the original arguments from the manifest with an empty list. To fully address the case described, it would be better to check if the slice has any elements before overwriting. This applies to both Command and Args.

Suggested change

	if container.Command != nil {
	dst.Command = container.Command
	}
	if container.Args != nil {
	dst.Args = container.Args
	}
	if len(container.Command) > 0 {
	dst.Command = container.Command
	}
	if len(container.Args) > 0 {
	dst.Args = container.Args
	}

[gemini-code-assist]

It's great that you're adding more logging. However, using context.TODO() should be avoided when a more specific context is available. In this function, ctx is passed as an argument and should be used here instead. This ensures that trace information and other context-scoped values are propagated correctly.

This same feedback applies to the other new logging calls in this file where ctx is available (e.g., in watchJob and Cleanup). For the logs in createJobFromManifestPath, which doesn't currently accept a context, consider refactoring that function to accept a context from its caller.

Suggested change

	olog.Entry(context.TODO()).Debugf("Creating verify job in cluster: %+v\n", job)
	olog.Entry(ctx).Debugf("Creating verify job in cluster: %+v\n", job)

[gemini-code-assist]

There's a typo here: 'Lookging' should be 'Looking'.

Suggested change

	olog.Entry(context.TODO()).Tracef("Lookging for container %s in %+v\n", container.Name, job.Spec.Template.Spec.Containers)
	olog.Entry(context.TODO()).Tracef("Looking for container %s in %+v\n", container.Name, job.Spec.Template.Spec.Containers)