Fix(close): Access to nil variable causes panic

[sonalys]

Please, accept this review for fixing a panic on the .Close() method.

[wneessen]

Thanks for catching this and providing the PR @sonalys! Much appreciated. Additionally I've created PR #354, so this case is covered by our test suite to make sure we don't introduce a regression for this at some point.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.55%. Comparing base (9ca7d24) to head (8c4eb62).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #353      +/-   ##
==========================================
- Coverage   91.74%   90.55%   -1.19%     
==========================================
  Files          27       27              
  Lines        2944     2944              
==========================================
- Hits         2701     2666      -35     
- Misses        172      212      +40     
+ Partials       71       66       -5     

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[sonalys]

Could you create a minor release for this issue?

I think it's a very critical one. It's happening for me, and I have to go around it with a defer recover.

[wneessen]

Yes, that should be possible.

[wneessen]

v0.5.2 is now released: https://github.com/wneessen/go-mail/releases/tag/v0.5.2

[sonalys]

v0.5.2 is now released: https://github.com/wneessen/go-mail/releases/tag/v0.5.2

You are supersonic! Thank you very much