[LOG4NET-486] Rolling File Appender with 'maxSizeRollBackups' and 'datePattern' does not detect existing logs initially

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.13
• Fix Version/s: 1.2.14
• Component/s: Appenders
• Labels: appender rolling
• Environment: Windows 8, Visual Studio 2013
• Flags: Important
• Assignee: Dominik Psenner
• Reporter: Simon Clark
• Created: 27/Oct/15 15:47
• Updated: 02/Nov/15 13:21
• Resolved: 01/Nov/15 19:02

Description

Rolling file appender with 'maxSizeRollBackups' set to a positive number tries to initialise by looking at existing log files to continue the rolling sequence and set 'm_curSizeRollBackups' to its correct value but the base filename format is wrong.

In method GetWildcardPatternForFile with m_preserveLogFileNameExtension true it should construct a wildcard pattern but the 'baseFileName' is not enough to fully identify the log file when 'datePattern' is also specified.

For example: -

With log files such as: -

MyLogFile_2015-10-27.1.log
MyLogFile_2015-10-27.2.log

the pattern created is 'MyLogFile.*.log'

The date pattern is missing and as a result no log files are found and historical log files get overwritten rather than rolled over.

A quick fix I'm using is to remove the '.' from the literal ".*" in the wildcard. This allows the OS to identify the log files. Later code makes a fuller check of the exact log file format and therefore this may be safe but I would think it needs more validation and testing to be sure this works under all circumstances.