As soon Fabrizio published his blog about the quality assurance of BlueMarine (blueCAT), I invited him to host his continuous integration in my personal Hudson lab. Everything nice and easy except for a strange error during the first attempt:

started
ERROR: svn: No credential to try. Authentication failed
org.tmatesoft.svn.core.SVNCancelException: svn: No credential to try. Authentication failed
	at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.cancel(SVNErrorManager.java:37)
	at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.cancel(SVNErrorManager.java:32)
	at org.tmatesoft.svn.core.internal.wc.DefaultSVNAuthenticationManager.getFirstAuthentication(DefaultSVNAuthenticationManager.java:167)
	at hudson.scm.FilterSVNAuthenticationManager.getFirstAuthentication(FilterSVNAuthenticationManager.java:38)
	at org.tmatesoft.svn.core.internal.io.dav.http.HTTPConnection.request(HTTPConnection.java:518)
	at org.tmatesoft.svn.core.internal.io.dav.http.HTTPConnection.request(HTTPConnection.java:257)
	at org.tmatesoft.svn.core.internal.io.dav.http.HTTPConnection.request(HTTPConnection.java:245)
	at org.tmatesoft.svn.core.internal.io.dav.DAVConnection.exchangeCapabilities(DAVConnection.java:454)
	at org.tmatesoft.svn.core.internal.io.dav.DAVConnection.open(DAVConnection.java:97)
	at org.tmatesoft.svn.core.internal.io.dav.DAVRepository.openConnection(DAVRepository.java:664)
	at org.tmatesoft.svn.core.internal.io.dav.DAVRepository.testConnection(DAVRepository.java:96)
	at hudson.scm.SubversionSCM$DescriptorImpl.checkRepositoryPath(SubversionSCM.java:1519)
	at hudson.scm.SubversionSCM.repositoryLocationsExist(SubversionSCM.java:1620)
	at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:455)
	at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:418)
	at hudson.model.AbstractProject.checkout(AbstractProject.java:801)
	at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:314)
	at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:266)
	at hudson.model.Run.run(Run.java:896)
	at hudson.model.Build.run(Build.java:112)
	at hudson.model.ResourceController.execute(ResourceController.java:93)
	at hudson.model.Executor.run(Executor.java:119)

The authentication failure warning was useless because we tried our passwords some times without any luck. After few minutes of frustration, we figured out the problem was caused by a misconfiguration of the SVN repositories accessed by blueMarine. It is probably documented somewhere in the Hudson pages (the impedance between humans and manuals, you know :).

The problem: SVNCancelException ... Authentication failed

When you configure a module in Hudson, it offers you a text field where you type the SVN URL and it also gives you a chance to type the user/password required to access the repository. Problem is: it only asks you 1 svn credential, but sometimes your module and its submodules access different repositories - what was exactly the case of blueMarine.

Solution:

The solution is simple but the useless error message and the lack of information in the Hudson GUI didn't helped at the first moment.

Hudson allows you to map diverse SVN URL to user/password credentials (or other authentication mechanism) - and not only the one asked by Hudson after you leave the text field. In order to do that, you need to click on the Help icon beside the text field and then to map all SVN repositories used by your application to the respective credentials.

After clicking the above buttons, an authentication mapper is shown and you have a chance to type how many repositories and password you need.

Nothing else to say, it is really simple to fix the problem as soon as you know what is about :) A last hint: for java.net projects you can use guest as user and leave the password blank - what is recommended to protect your password and also to guarantee the code downloaded in the host machine will have read-only access to the SVN - protecting also the code in case a hacker comes for a visit...

Hudson rocks !