XmlLayoutSchemaLog4J: Changed XML start element for exceptions since v3.0.0

[sita-martin]

Until v2.0.17 exceptions were written with the start element log4j:throwable in an XML. Since version 3.0.0 this has changed to log4j:data.
i.e.
v2.0.17
<log4j:data>System.TimeoutException: throw timeout</log4j:data>
v3.0.3
<log4j:throwable>System.TimeoutException: throw timeout</log4j:throwable>

In my opinion this not correct and has to be changed back.
Line 224 in the XmlLayoutSchemaLog4J.cs:
writer.WriteStartElement("log4j:throwable", "log4j", "data", "log4net") => IMHO not correct
writer.WriteStartElement("log4j:throwable", "log4j", "throwable", "log4net") => correct

Thanks for any feedback.

[FreeAndNil]

Hi @sita-martin,

I created a test to reproduce your problem.

[Test]
public void LogExceptionTest()
{
  XmlLayoutSchemaLog4J layout = new();
  StringAppender stringAppender = new() { Layout = layout };

  ILoggerRepository rep = LogManager.CreateRepository(Guid.NewGuid().ToString());
  BasicConfigurator.Configure(rep, stringAppender);
  ILog log1 = LogManager.GetLogger(rep.Name, "TestLogger");
  Bar(42);

  var x = stringAppender.GetString();

  void Bar(int foo)
  {
    try
    {
      throw new TimeoutException();
    }
    catch (TimeoutException ex)
    {
      log1.Error(string.Format("Error {0}", foo), ex);
    }
  }
}

This test gives me the same result for 2.0.17 and 3.0.3.

<log4j:event logger="TestLogger" timestamp="1738662416975" level="ERROR" thread="17">
  <log4j:message>Error 42</log4j:message>
  <log4j:properties>
    <log4j:data name="log4net:HostName" value="pcname"/>
    <log4j:data name="log4jmachinename" value="pcname"/>
    <log4j:data name="log4japp" value="domain-c35c8fe6-log4net.Tests.dll"/>
    <log4j:data name="log4net:UserName" value="username"/>
  </log4j:properties>
  <log4j:throwable><![CDATA[System.TimeoutException: The operation has timed out.
   at log4net.Tests.Layout.XmlLayoutSchemaLog4jTest.<LogExceptionTest>g__Bar|0_0(Int32 foo, <>c__DisplayClass0_0& ) in X:\logging-log4net\src\log4net.Tests\Layout\XmlLayoutSchemaLog4jTest.cs:line 51]]></log4j:throwable>
</log4j:event>

[sita-martin]

Hi @FreeAndNil

thanks for your feedback.

I'm sorry, i have created a test project based on your test. And I'm still see the issue. I add the log4net reference through Nuget - when I switch between v2.0.17 and 3.0.3 I have to adjust the layout spelling (the j at the end becomes J).
I attached my sample project.
Please tell me what I'm doing wrong.
Best regards

log4Net_Test.zip

[FreeAndNil]

@sita-martin I'm sorry, I must have copied the wrong output.
I fixed the bug in #226

I could create a preview version until the end of the week.
Could you test this version?

[sita-martin]

@FreeAndNil That would be great. And yes, i will test a preview version immediately and let you know my findings.
Thank you

[FreeAndNil]

@sita-martin see https://github.com/apache/logging-log4net/releases/tag/rc%2F3.0.4-preview.1
and https://www.nuget.org/packages/log4net/3.0.4-preview.1