✨ Quality: shutil.which() return value not checked before os.path.dirname()

[Manhhoangvp95]

✨ Code Quality

Problem

On non-Windows platforms, shutil.which("kubectl") returns None if the
executable is not found. The code then calls os.path.dirname(full_path)
which will raise TypeError: expected str, bytes or os.PathLike object, not NoneType.
This will crash at runtime when kubectl is not installed.

Severity: high
File: installer/common/file_utils.py

Solution

Add a check for None: if full_path is None: raise RuntimeError("kubectl not found")
or return a sensible default.

Changes

• installer/common/file_utils.py (modified)

Summary

Changes

Testing

Possible Regressions

Checklist

• Read the contributions page.
• Submitted the CLA form, if you are a first time contributor.
• The introduced changes are covered by unit and/or integration tests.

Notes

Closes #5412

[Copilot]

Pull request overview

Improves robustness of the installer’s kubectl path discovery by handling the case where shutil.which("kubectl") returns None on non-Windows platforms, preventing an immediate TypeError from os.path.dirname(None).

Changes:

• Add a None guard around shutil.which("kubectl") in get_kubectl_directory() with a fallback directory.

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[Copilot]

Please add a unit test covering the shutil.which("kubectl") is None branch (and the expected behavior you choose—exception vs fallback). This logic is easy to regress and the repo already has unit test coverage for other installer/common helpers.

[louiseschmidtgen]

Hi @Manhhoangvp95,
Thank you for contributing to MicroK8s.

• 1 on copilots comment: Let's not try to guess where the kubectl installation lives ("/usr/local/bin") and instead fail with a sensible error.