Fix fifocache evict for 1.2

[LeftHandCold]

User description

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #16443

What this PR does / why we need it:

When the cache evicts, although the values in cache's shards are deleted,
there are still references in queue1, so fix.

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PR Type

Bug fix

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Description

• Fixed an issue in the FIFO cache eviction process where dequeued values were not being properly zeroed out, causing lingering references in the queue.
• This change ensures that after a value is dequeued, it is set to zero, preventing potential memory leaks or unexpected behavior.

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Changes walkthrough 📝

	Relevant files
Bug fix	queue.go Fix lingering references in FIFO cache eviction                    pkg/fileservice/fifocache/queue.go Set dequeued value to zero after removal to avoid lingering references. +2/-0

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💡 PR-Agent usage:
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PR Review 🔍

⏱️ Estimated effort to review [1-5]	2, because the PR involves a small change in a specific part of the code, which is setting a dequeued value to zero to avoid lingering references. The change is straightforward and localized, making the review process relatively quick and easy.
🧪 Relevant tests	No
⚡ Possible issues	Possible Bug: If the type T has a destructor or requires special handling when zeroed, simply setting it to zero might not properly clean up the resources. This needs to be verified depending on what T represents in this context.
🔒 Security concerns	No

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PR Code Suggestions ✨

Category	Suggestion	Score
Possible bug	Add a check to reset p.tail.begin to 0 if it reaches the end of the slice Consider adding a check to see if p.tail.begin has reached the end of the slice and reset it to 0 if necessary. This will prevent potential out-of-bounds errors in future operations. pkg/fileservice/fifocache/queue.go [89] p.tail.begin++ +if p.tail.begin >= len(p.tail.values) { + p.tail.begin = 0 +} Suggestion importance[1-10]: 8 Why: This suggestion addresses a potential bug that could lead to out-of-bounds errors, which is a critical issue in array manipulation.	8
Possible issue	Add a nil check for p.tail to prevent potential nil pointer dereference Consider adding a check to ensure p.tail is not nil before accessing its values to avoid potential nil pointer dereference. pkg/fileservice/fifocache/queue.go [86] -ret = p.tail.values[p.tail.begin] +if p.tail != nil { + ret = p.tail.values[p.tail.begin] +} Suggestion importance[1-10]: 8 Why: This suggestion prevents a common and dangerous error in Go, which is a nil pointer dereference, thus it's a crucial improvement.	8
Best practice	Add a comment to explain the purpose of resetting the value to its zero value Add a comment explaining why the zero value is being assigned to p.tail.values[p.tail.begin] to clarify the intention behind this line of code. pkg/fileservice/fifocache/queue.go [88] +// Reset the value to its zero value to avoid memory leaks p.tail.values[p.tail.begin] = zero Suggestion importance[1-10]: 7 Why: Adding a comment improves code readability and helps future maintainers understand the purpose of resetting the value, which is a good practice.	7
Enhancement	Rename the variable zero to defaultValue for better readability To improve readability and maintainability, consider renaming the variable zero to something more descriptive, such as defaultValue. pkg/fileservice/fifocache/queue.go [87] -var zero T +var defaultValue T Suggestion importance[1-10]: 6 Why: Renaming the variable to defaultValue enhances code readability and maintainability, but it's a relatively minor enhancement.	6

[matrix-meow]

@LeftHandCold Thanks for your contributions!

Pull Request Review:

Title:

The title "Fix fifocache evict for 1.2" is clear and indicates the purpose of the pull request.

Body:

The body of the pull request provides useful information about the type of PR, the related issue, and a brief description of the changes made. It also includes a walkthrough of the changes with a link to the specific file modified.

Changes Made:

1. In the queue.go file, a fix was implemented to address lingering references in the FIFO cache eviction process by setting the dequeued value to zero after removal.

Feedback and Suggestions:

1. Memory Leak Issue:

   • The fix implemented in the pull request is addressing a memory leak issue where dequeued values were not properly zeroed out, leading to lingering references in the queue. This could potentially cause memory leaks or unexpected behavior.
   • Suggestion: The approach of setting the dequeued value to zero after removal is appropriate to prevent memory leaks. However, it would be beneficial to ensure that all references to the dequeued value are properly cleaned up to avoid any potential memory leaks in the future.

2. Code Optimization:

   • The change made in the queue.go file is straightforward and directly addresses the identified issue.
   • Suggestion: Since the fix is simple and focused, no further optimization is necessary for this specific change. However, it's always good practice to review the surrounding code to ensure consistency and adherence to best practices.

3. Documentation:

   • While the pull request body provides a clear description of the changes made, it would be beneficial to include more detailed information about the impact of the fix and any potential risks associated with the previous behavior.
   • Suggestion: Consider adding additional details in the pull request description to help reviewers and future developers understand the significance of the fix and its implications.

4. Testing:

   • It's important to verify that the fix resolves the memory leak issue effectively without introducing any regressions.
   • Suggestion: Include relevant test cases to validate the fix and ensure that the FIFO cache eviction process functions correctly after the changes are applied.

5. Security Considerations:

   • While the fix primarily addresses a memory leak issue, it's crucial to consider any potential security implications related to improper memory handling.
   • Suggestion: Conduct a thorough review of the codebase to identify and address any other potential security vulnerabilities, especially in memory management and data handling processes.

In conclusion, the pull request addresses a specific memory leak issue in the FIFO cache eviction process. By ensuring that dequeued values are properly zeroed out, the risk of memory leaks is mitigated. To enhance the quality of the codebase further, consider incorporating the suggestions provided above and conducting thorough testing to validate the fix.