Hello everyone!

I've come across an issue with RollingFileAppender, but I'm not sure if it's us or logback.

<configuration>

    <timestamp key="currentDate" datePattern="yyyy_MM_dd" />

    <appender name="dataServiceRequestLog" class="ch.qos.logback.core.rolling.RollingFileAppender">
<param name="File" value="${the.log.dir}/${currentDate}.WebService.log"/>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<FileNamePattern>${the.log.dir}/%d{yyyy_MM_dd}.WebService.log</FileNamePattern>
<MaxHistory>30</MaxHistory>
</rollingPolicy>
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level - %msg%n</pattern>
        </encoder>
</appender>

The curious part is that File matches the FileNamePattern for the rolling policy ("${the.log.dir}/${currentDate}.WebService.log" and "${the.log.dir}/%d{yyyy_MM_dd}.WebService.log").

Do you guys think that's OK?  The intention is that there's a separate file for every day:
The issue we're experiencing is seemingly random writes to old log files (e.g., today we saw writes to 2013_01_04.WebService.log). Could this be the rename problem?

Perhaps there's a better way to achieve the desired functionality.  Is this worth writing a unit test for in RollingFileAppenderTest.java?

Any tips are greatly appreciated, thanks!