The plugin fails to read the XML log file produced by the maven spy under the following circumstances:

• maven is executed with ANSI color enabled
• a plugin execution fails to execute 

The maven spy captures the exception thrown by the failed execution and writes it asis in its XML log file. Unfortunately, it appears that the exception message contains ANSI color escape codes when maven is executed with coloring enabled. These escape codes are not valid XML content hence causing the failure to read back the XML log file.

The issue can be easily reproduced with the attached sample pom.xml.

Note: according to issue JENKINS-55318, coloring is not working because the plugin always invoke maven in batch mode. Our Jenkins installation is actually using a kind of post-processor that removes the --batch-mode argument from the generated wrapper script... so we have coloring working nicely.