added a probe to investigate a failure at

http://kohsuke.sfbay/hudson/job/jaxws-ri-unit-pre-jaxws21-optimistic/lastBuild/console


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@1595 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/scm/CVSSCM.java

@@ -210,7 +210,10 @@ public class CVSSCM extends AbstractCVSFamilySCM implements Serializable {
                         if(!mf.isDirectory()) {
                             // this module is just a file, say "foo/bar.txt".
                             // to record "foo/CVS/*", we need to start by archiving "foo".
-                            m = m.substring(0,m.lastIndexOf('/'));
+                            int idx = m.lastIndexOf('/');
+                            if(idx==-1)
+                                throw new Error("Kohsuke probe: m="+m);
+                            m = m.substring(0, idx);
                             mf = mf.getParentFile();
                         }
                         archive(mf,m,zos);