Fix panic in job controller's killPods action

[neo502721]

What type of PR is this?

/kind bug

What this PR does / why we need it:

In the killPods function, directly accessing pod from jobInfo.Pods[target.TaskName][target.PodName]
could cause a nil pointer dereference error when target.Type is TargetTypePod. This is because
if target.TaskName does not exist in jobInfo.Pods, or target.PodName does not exist in the
corresponding task, accessing this map would cause a panic.

This fix prevents direct access to potentially non-existent map keys by checking if the task
and pod exist, thereby preventing nil pointer dereference errors.

Which issue(s) this PR fixes:

Fixes #4543

Special notes for your reviewer:

Does this PR introduce a user-facing change?

[volcano-sh-bot]

Welcome @neo502721!

It looks like this is your first PR to volcano-sh/volcano.

Thank you, and welcome to Volcano. 😃

[gemini-code-assist]

Summary of Changes

Hello @neo502721, 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 resolves a critical bug in the job controller's killPods action that could lead to a nil pointer dereference. Previously, direct access to jobInfo.Pods using potentially non-existent target.TaskName or target.PodName could cause the application to panic. The fix introduces robust checks to validate the existence of these keys before map access, significantly enhancing the stability and reliability of the job controller's pod termination logic.

Highlights

• Bug Fix - Nil Pointer Dereference: Addresses a potential nil pointer dereference in the killPods function within the job controller.
• Robust Map Access: Implements checks for the existence of target.TaskName and target.PodName in the jobInfo.Pods map before attempting to access their values, preventing panics.
• Improved Error Prevention: Ensures that the podsToKill map is populated safely, even if the target task or pod does not exist in the jobInfo.Pods structure.

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[neo502721]

/assign @hzxuzhonghu

[gemini-code-assist]

Code Review

This pull request correctly addresses a potential nil pointer dereference in the killPods function by adding necessary checks before accessing nested maps. The fix is direct and effective. I've included one suggestion to refactor the conditional logic using a switch statement, which could improve readability and maintainability.

[gemini-code-assist]

The if-else if structure works, but using a switch statement on target.Type would be more idiomatic Go in this case. It improves readability and makes the code more extensible if more TargetType values are added in the future.

Suggested change

	if target.Type == state.TargetTypeTask {
	podsToKill = jobInfo.Pods[target.TaskName]
	if targetPods, found := jobInfo.Pods[target.TaskName]; found {
	podsToKill = targetPods
	}
	} else if target.Type == state.TargetTypePod {
	podsToKill[target.PodName] = jobInfo.Pods[target.TaskName][target.PodName]
	if targetPods, found := jobInfo.Pods[target.TaskName]; found {
	if pod, found := targetPods[target.PodName]; found {
	podsToKill[target.PodName] = pod
	}
	}
	}
	switch target.Type {
	case state.TargetTypeTask:
	if targetPods, found := jobInfo.Pods[target.TaskName]; found {
	podsToKill = targetPods
	}
	case state.TargetTypePod:
	if targetPods, found := jobInfo.Pods[target.TaskName]; found {
	if pod, found := targetPods[target.PodName]; found {
	podsToKill[target.PodName] = pod
	}
	}
	}

[hzxuzhonghu]

/ok-to-test

[hzxuzhonghu]

genrally lg, could you add a test case for it

[neo502721]

genrally lg, could you add a test case for it
Okay, I will add it later today.

[xanderdunn]

Thanks so much for this fix, really appreciate it!

[volcano-sh-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hzxuzhonghu

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• pkg/controllers/OWNERS [hzxuzhonghu]

Approvers can indicate their approval by writing /approve in a comment
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[kingeasternsun]

/lgtm