google code svnsync Error setting property

When I tried to sync a local repository to google code project host, I
got the Error setting property.
yang@acer:~$ svnsync init https://yangs.googlecode.com/svn file:///home/yang/code.google/
yang@acer:~$ svnsync sync https://yangs.googlecode.com/svn
.......
Committed revision 7.
Copied properties for revision 7.
Transmitting file data ................
Committed revision 8.
svnsync: Error setting property 'log'
svnsync: At least one property change failed;
repository is unchanged
svn: Error setting property 'log'
Could not execute PROPPATCH
After somewhat hours of googling, I didn't find any direct solution for
my problem, although it did help me get an general understanding of
several keyword in the err log:
PROPPATCH is an http method used in WebDav, just like GET, POST, and
PUT.
property is some technology SVN used to store additonal
information about the files in a repository.
Okay, let's go back to my problem, and its solution. In fact, it's easy,
and all included in the svn help. I didn't realize this until I went
back to the svnbook after long time unsuccessful attempts to google the
solution.
The Err message tells you that something wrong happened while setting a
property 'log'. Exactly speaking, it's the 'log' property of revision 8,
as the err happened right after revision 7's commit job was done. So, to
solve the problem, you need to check and repair the 'log' property of
r8, with the folling command:
svn propedit --revprop svn:log file:///home/yang/code.google/ -r8
In my case, it's some unknown blank new lines at the end of the 'log'
property. After remove them, and the command svnsync went through
without any problem.
Hope this will help those who encounter the same/similar questions, and
the lesson I learned from this experience, again: read the manual~