NullRefException from shutdown in 2.0.16

[erikmav]

This commit introduced after 2.0.15 results in an NRE during some shutdown cases where m_lockingModel is null during Close/Dispose.

The simplistic fix is to add a check to FileAppender. The better fix is to enable nullability on FileAppender, RollingFileAppender, and their unit tests, and fix all nullability problems.

A fix is needed as a 2.0.17 package in addition to the proposed 3.0 package.

[erikmav]

@FreeAndNil

[FreeAndNil]

Thanks for reporting.
I will take a look.

[erikmav]

I'm putting together a large PR with the nullability setting change. It's a lot to review so for faster release it's probably better to fix the dispose case as a quick fix then ship 2.0.17.

[FreeAndNil]

@erikmav I agree. Please rebase/start your nullability PR on Feature/111-Dropping-support-for-older-runtimes.
Will you provide the quick fix or should I do?

[erikmav]

Can you add the quick fix? I'm heads-down on the large PR.

[erikmav]

@FreeAndNil Small and large PRs posted.

[FreeAndNil]

Will be fixed in 2.0.17 (2024-03-22).

[andreycha]

Hi @FreeAndNil any ETA when 2.0.17 stable version is going to be released? I need some changed from 2.0.16 but don't want to upgrade without this hotfix.

[FreeAndNil]

@andreycha definitely next week.

[FreeAndNil]

@andreycha
https://github.com/apache/logging-log4net/releases/tag/rel%2F2.0.17
https://www.nuget.org/packages/log4net/2.0.17

[andreycha]

@FreeAndNil thanks a lot!