We are also seeing this. We support multiple Hudson servers connecting to
multiple SVN repositories; all the Hudson servers are hosted on Red Hat linux
virtual machines. The Hudson servers are time sync'd with the SVN servers.

One effect is that where projects poll for changes they may occasionally miss an
opportunity to build, so it can be up to twice the polling interval between the
change to SVN and the build starting. When using "build now", we have to wait
for a minute or so before pushing the button.

I would like to understand how Hudson's SVN polling detects changes? Is the
problem likely to be in Hudson's polling code, or the underlying SVN access
library? Why are the dates on the servers even relevant? Can Hudson not detect
changes based on revision numbers alone?

Same error with SVN here :
"WARNING: clock of the subversion server appears to be out of sync. This can
result in inconsistent check out behavior."

We recently change our source repository (svn dump && restore && new checkout)
and then hudson started to produce the above error message.

Disabling the use of update (svn will do a full checkout) did not solve the problem.

So currently, whenever we do a build (manually or by trigger), Hudson is "late".

Test case :

• Hudson is setup to receive an event from SVN to launch the build (trigger)
• I do a commit : SVN message : "Committed revision 20946"
• Hudson fires a build
• Hudson console output Updating[...] At revision 20945
• Hudson then prints : WARNING: clock of the subversion server appears to be out
  of sync. This can result in inconsistent check out behavior.

Of course the server (SVN, hudson) are synchronized...

Hi,
I took a look at the code and it seems that hudson compares its date with the
date on the SVN server. If the date on hudson is after the date on the SVN,
hudson doesn't checkout the project.

Is there any reason for this? I would leave the warning message but I think that
hudson should always checkout the last version.

I am still investigating on this anyway.

@davidedalto
From what I see the comparison is only used to print the warning and does not influence the checkout/update.

The basic reason for the polling problems and the warning seems to be that in CheckOutTask#getRevision the svn plugin defaults to selecting a revision based on the timestamp of the build. This means that when the clock on the SVN server is ahead of the clock on the Hudson machine an older revision may be selected.
Why it doesn't default to HEAD instead, I'm not sure, so I assume there must be a good reason. (Is the build timestamp used determined when the build is queued or when it is started?)
Maybe the problem could be diminished with the help of a post-commit hook if the plugin did use the rev parameter shown in the wiki example, but apparently it is unused now.

lost some hours to this, couple of simple things that would help, that wouldn't require a full fix:

• show warning message even if build is started manually
• include timezone info on main page (lower right corner of screen), right now only time/date is shown

What the Subversion plugin as of 1.37 (and it's been like this for a while) is that we ask the Subversion repository to tell us when the last revision was committed, and if that's coming from the future timestamp than the time of the check, then issue this warning.

So if you are seeing this, your Subversion server is really out of sync with the slave where the build is happening.

To make builds consistent (especially for matrix projects), we do timestamped check out, which is why we can't just check out HEAD.

Hi,

We have this situation where the environment in which the Jenkins server runs, although it has the same timezone as the SVN server, it is intentionally out of synch (long story, but this is how it is...)
Because of this issue, we can only build with @HEAD added to the SVN repo URL, but, as you mentioned, this means distributed building is no longer safe.
My suggestion is to use a revision number instead of a timestamp to uniquely identify the build's source tree.

Is this doable?

Thank you

The same problem here. Once a commit is made during the time when SVN server is out of sync (let's say one month ahead the current time), there is no way for you to have the job check out the latest rev again(it's always stuck at some rev ahead of that "guilty" commit). Although I've tried to clean up the working copy & check out again. The only workaround is added @HEAD to the repo URL. This is really frustrating