Unable to set property [file] on object [log4net.Appender.FileAppender]

[sc-mk]

Hi,

We use the following in log4net.config for log4net 2.0.17:

<file type="log4net.Util.PatternString" value="Logs\file_%property{LogName}_%date{yyyyMMddHHmmss}.log" />

I updated log4net to latest version 3.0.0 via NuGet Manager in Visual Studio.
I got the following error:

Message: 
TestCleanup method Test.XYZ.TestCleanup threw exception. System.ArgumentException: System.ArgumentException: The parameter should not be null or empty.
Parameter name: fileName.

Stack Trace:
EqtAssert.StringNotNullOrEmpty(String parameter, String parameterName)
TestContextImplementation.AddResultFile(String fileName)
Logger.AttachLogFile(TestContext testContext) line 31
XYZ.TestCleanup() line 51

Standard Error: 
log4net:WARN Unable to set property [file] on object [log4net.Appender.FileAppender] using value [Logs\file_%property{LogName}_%date{yyyyMMddHHmmss}.log] (with acceptable conversion types)
log4net:WARN FileAppender: File option not set for appender [GeneralFileAppender].
log4net:WARN FileAppender: Are you using FileAppender instead of ConsoleAppender?

If I delete the type="log4net.Util.PatternString" from log4net.config, the log file will be created.
Otherwise no, it does not create a file.

Can you advise me what is wrong?

This worked for years until I upgraded to version 3.0.0

<configuration>
  <configSections>
    <section name="log4net" type="log4net. config.Log4NetConfigurationSectionHandler, log4net"/>
  </configSections>
  <log4net>
    <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date{ABSOLUTE} [%logger] %level - %message%newline%exception"/>
      </layout>
    </appender>
    <appender name="GeneralFileAppender" type="log4net.Appender.FileAppender">
      <file type="log4net.Util.PatternString" value="Logs\file_%property{LogName}_%date{yyyyMMddHHmmss}.Log"/>
      <appendToFile value="true"/>
      <lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date{ABSOLUTE} [%logger] %level - %message%newline%exception"/>
      </layout>
    </appender>
    <root>
      <level value="INFO"/>
      <appender-ref ref="GeneralFileAppender"/>
    </root>
  </log4net>
</configuration>

[ppkarwasz]

Probably a typo in your config: the parameter name is fileName not file. Can you show us your configuration file?

[FreeAndNil]

The property name is "file" in log4net, but it would be helpful to see the config file (the whole log4net section).

[geirg71]

I also have this error after upgrading from log4net 2.0.17 to 3.0.0:

log4net:WARN Unable to set property [File] on object [log4net.Appender.RollingFileAppender] using value [mylog.log] (with acceptable conversion types)
log4net:ERROR Could not create Appender [RollingFileAppender] of type [log4net.Appender.RollingFileAppender]. Reported error follows.
System.NullReferenceException: Object reference not set to an instance of an object.
   at log4net.Appender.RollingFileAppender.ActivateOptions() in C:\log4net\src\log4net\Appender\RollingFileAppender.cs:line 993
   at log4net.Repository.Hierarchy.XmlHierarchyConfigurator.ParseAppender(XmlElement appenderElement) in C:\log4net\src\log4net\Repository\Hierarchy\XmlHierarchyConfigurator.cs:line 334
log4net:ERROR Appender named [RollingFileAppender] not found.

As @mariankral said, if I remove type="log4net.Util.PatternString" from the config file the problem disappers.

An Internet search shows that there are many config files around using type="log4net.Util.PatternString" this way. Hence I guess this 3.0.0 change will probably break many configurations.

Random example (I have no connection to earthsoft):

https://help.earthsoft.com/ent_configure-log4net.htm

<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
  <file type="log4net.Util.PatternString" value="%env{temp}/equislogs/{baseUri}/{process}.log" />
  <param name="AppendToFile" value="true" />
  <param name="MaxSizeRollBackups" value="10" />
  <param name="MaximumFileSize" value="500KB" />
  <param name="RollingStyle" value="Size" />
  <param name="StaticLogFileName" value="true" />
  <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
  <layout type="log4net.Layout.PatternLayout">
    <param name="ConversionPattern" value="%d %property{url} %property{ip} [%t] %-5p %c [%x] - %m%n" />
  </layout>
</appender>

[sc-mk]

@ppkarwasz @FreeAndNil
I added the whole config file.
I also tried with fileName, but result was the same error.

[FreeAndNil]

@sc-mk, @geirg71 I can reproduce the issue in an unit test and verified that the problem does not occur in 2.x
I'm working on a fix.

[FreeAndNil]

@sc-mk, @geirg71 Thanks for reporting the problem.

I fixed the regression in #184

Can you please test with https://github.com/apache/logging-log4net/releases/tag/rc%2F3.0.1-preview.2 or https://www.nuget.org/packages/log4net/3.0.1-preview.2 and close the issue?

[geirg71]

Thank you @FreeAndNil I tested with 3.0.1-preview.2, and the problem is solved in my environment. I leave the issue closing to @sc-mk.