[slf4j-dev] slf4j 2.0.0-alpha6 still referring to log4j 1.x

Ralph Goers rgoers at apache.org
Mon Jan 24 03:52:38 CET 2022


Ceki, I am not talking about backward compatibility with users using the API. 
I am talking about compatibility with logging implementations. That has been 
broken several times and is why we have a log4j-slf4j-impl, a log4j-slf4j18-impl, 
and will now need a log4j-slf4j20-impl. It is also why Log4j cannot compile with 
SLF4J 1.7 versions greater than 1.7.25 since the EventData class was removed 
and Log4j 2 provides compatibility support for that. 

So that is at least 4 times compatibility between SLF4J and underlying implementations has 
been broken.

He also has the option of using log4j-1.2-api in the upcoming 2.17.2 release. One 
of our PMC members just went through the exercise of migrating all of his log4j 
1.2.x applications using it and was able to get all of his applications working using it.
This is for both the API, configuration files, and some of the standard things users 
do in their code with Log4j 1.x.

I do notice, however, that you did not mention anything about fixing the issue with 
obtaining location information in the fluent API. Have you addressed that yet?

Ralph

> On Jan 23, 2022, at 5:03 PM, Ceki Gülcü <ceki at qos.ch> wrote:
> 
> 
> Ralph,
> 
> If I remember correctly, you lobbied for LocationAwareLogger to admit an
> additional Object[] parameter. This change was made in SLF4J version 1.6
> at your behest. This broke backward compatibility with 1.5 bindings.
> This was the only time backward compatibility was broken between 1.0 and
> 1.7, or in over 15 years.
> 
> It is rather ironic that you should imply on this mailing list that
> SLF4J does not care about backward compatibility.
> 
> On another register, reload4j 1.2.18.2 fixed the log4j 1.x CVEs you
> published recently. It was quite nice of you to file them. Thank you so
> much. So, as of 1.2.18.2 Vijay has the option to use reload4j as an
> alternative to log4j{1,2}.
> 
> Best regards,
> -- 
> Ceki Gülcü
> 
> Sponsoring SLF4J/logback/reload4j at https://github.com/sponsors/qos-ch
> 
> On 1/23/2022 7:10 PM, Ralph Goers wrote:
>> Support for SLF4J is provided by Log4j 2. However, support for 2.0.0-*
>> has not yet been implemented because a) AFAIK SLF4J-511 has still not
>> been fixed so it isn’t possible to get the fluent api to have correct
>> location information and b) Ceki is known to change things that affect
>> compatibility of implementations in alpha and beta releases since alpha
>> and beta releases aren’t guaranteed to be production ready by definition.
>> 
>> Ralph
>> 
>>> On Jan 21, 2022, at 7:03 AM, Vijayendhiran M
>>> <vijayendhiran.m at globallogic.com
>>> <mailto:vijayendhiran.m at globallogic.com>> wrote:
>>> 
>>> Hi Team,
>>> 
>>>  
>>> 
>>> We are trying to upgrade slf4j to the latest version 2.0.0-alpha6
>>> <https://mvnrepository.com/artifact/org.slf4j/slf4j-api/2.0.0-alpha6>.
>>> We have noticed that it is still referring to log4j 1.x. We need to
>>> upgrade log4j version 2.x in our application. Looking for your support.
>>> 
>>>  
>>> 
>>> Thanks,
>>> Vijay. 
> 
> 
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