In Eclipse, I chose two projects to merge and then report. One project had test failures. The merge succeeds but the report fails with:
ERROR: Velocity.Method linkifyStackTrace threw exception for reference $renderUtil in template html_res/test-class-summary.vm at [64,108]
ERROR: A problem was encountered while rendering the report: Invocation of method 'linkifyStackTrace' in class com.cenqua.clover.reporters.html.HtmlRenderingSupport threw exception class java.lang.NullPointerException : null
Perhaps the stack traces aren't copied over during a merge? I don't have time to track this down right now.