As one of the committers to the Subversion project itself, I noticed
that revision 11085 has no log message:

$ svn log -r 11085 http://lampsvn.epfl.ch/svn-repos/scala
------------------------------------------------------------------------
r11085 | spoon | 2007-05-18 01:01:47 -0700 (Fri, 18 May 2007) | 1 line


------------------------------------------------------------------------


Please consider enabling the feature in Subversion's pre-commit
script to reject commits without a log message, as having
no log message is considered bad practice.

Something like this works nicely in the pre-commit.

# Make sure that the log message contains some text.
SVNLOOK=/usr/local/bin/svnlook
$SVNLOOK log -t "$TXN" "$REPOS" | grep "[a-zA-Z0-9]" > /dev/null || {
  echo "$0: no log message for txn $TXN" 1>&2
  exit 1
}

Regards,
Blair