fix: close temp file handle before removal

[acouvreur]

What does this PR do?

When using LoadFile on dind or k3s, the temporary file descriptor is not closed.

On some OS (such as windows), this fails upon deletion of the temp file.

Why is it important?

Related issues

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 8de3e8de-d0e1-4f01-9e1b-cc22f1bc88c8

📥 Commits

Reviewing files that changed from the base of the PR and between 0c15e97 and f8e88af.

📒 Files selected for processing (2)

• modules/dind/dind.go
• modules/k3s/k3s.go

---

Summary by CodeRabbit

• Bug Fixes
  • Enhanced file handling in container image loading operations with explicit closure of temporary files and proper error checking to ensure reliable and consistent operation.

Walkthrough

Both the DinD and K3s container image loading modules add explicit closure of temporary image tar files immediately after creation. Each module now checks for close errors and returns a wrapped error before proceeding with file operations. Deferred cleanup remains unchanged.

Changes

Temporary File Resource Management

Layer / File(s)	Summary
DinD File Closure modules/dind/dind.go	LoadImage adds explicit close of the temporary images file right after creation, with error wrapping for close failures, before using the file path for SaveImages, CopyFileToContainer, and image load operations. Deferred cleanup unchanged.
K3s File Closure modules/k3s/k3s.go	LoadImagesWithOpts follows the same pattern: closes the temporary file immediately after creation with dedicated error handling, then proceeds with SaveImagesWithOpts, CopyFileToContainer, and image import operations.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A file to hold, then let it go,
Before its path begins to flow,
Close it quick, check if all's well,
Then use that path—a simple spell!
Two modules sync, no leaks remain,
Resources freed, the code's more sane. 🧡

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: closing temporary file handles before removal to fix platform-specific deletion failures.
Description check	✅ Passed	The description is directly related to the changeset, explaining the problem (unclosed file descriptor on Windows) and the motivation for the fix.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[mdelapenya]

LGTM! I recently saw something similar for other project on Windows, so this makes sense, thanks!