[jira] [Comment Edited] (LOG4NET-501) Finalization of appenders might fail

["Matthias Hess (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LOG4NET-501?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16322929#comment-16322929 ] 

Matthias Hess edited comment on LOG4NET-501 at 1/11/18 8:54 PM:
----------------------------------------------------------------

Hi, I guess my point was this:
{quote}The finalizers of two objects are not guaranteed to run in any specific order, even if one object refers to the other. That is, if Object A has a reference to Object B and both have finalizers, Object B might have already been finalized when the finalizer of Object A starts.
{quote}
taken from https://msdn.microsoft.com/en-us/library/system.object.finalize.aspx

I can't remember this issue exactly and I haven't looked into the code today, but I assume that RollingFileAppender has a Finalizer just like the FileStream has one. RollingFileAppender (Object A) references the FileStream (Object B) directly or indirectly. Finalization happens in undefined order: in my observed case, apparently the FileStream was finalized *before* the RollingFileAppender. Hence, RollingFileAppender failed to write a footer and flush the FileStream in its own finalizer implementation.


was (Author: m.hess):
Hi, I guess my point was this:
> The finalizers of two objects are not guaranteed to run in any specific order, even if one object refers to the other. That is, if Object A has a reference to Object B and both have finalizers, Object B might have already been finalized when the finalizer of Object A starts.
taken from https://msdn.microsoft.com/en-us/library/system.object.finalize.aspx

I can't remember this issue exactly and I haven't looked into the code today, but I assume that RollingFileAppender has a Finalizer just like the FileStream has one. RollingFileAppender (Object A) references the FileStream (Object B) directly or indirectly. Finalization happens in undefined order: in my observed case, apparently the FileStream was finalized *before* the RollingFileAppender. Hence, RollingFileAppender failed to write a footer and flush the FileStream in its own finalizer implementation.

> Finalization of appenders might fail
> ------------------------------------
>
>                 Key: LOG4NET-501
>                 URL: https://issues.apache.org/jira/browse/LOG4NET-501
>             Project: Log4net
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.2.10
>            Reporter: Matthias Hess
>
> Given the following example:
> {code}
>             LogLog.InternalDebugging = true;
>             RollingFileAppender result = new RollingFileAppender();
>             result.File = ...;
>             result.AppendToFile = true;
>             result.Encoding = Encoding.UTF8;
>             ...
>             result.ActivateOptions();
> {code}
> When this rolling file appender object gets finalized (due to no more references), the finalization code tries to close the underlying file stream. This will fail, if the underlying file stream itself was already subject to finalization.
> It gives me log4net internal error messages when using the appenders outside of a logger repository.
> I think, the current finalization code does a little too much. Writing a footer/flushing should be triggered by the AppDomain events only.
> What do you think about it?



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)