tests/test-check-commit-hg.t

revset: add helper to build balanced addsets from chained 'or' operations

This function will be used by revset.orset() and scmutil.revrange() to reduce
the stack depth from O(n) to O(log(n)).

We've bikeshed the interface of this function, but we couldn't come to an
agreement. So we decided to attempt to make it move forward.

 marmoute:
 - new factory function isn't necessary for balanced addsets
 - addset.__init__ can just recurse, should handle "len(subsets) == 2+"

 yuja:
 - want to write all "len(subsets) == 0, 1, 2, 3+" cases in the same function
 - no recursion in __init__ for cosmetic reason: can't return, can't call
   __init__ directly

I've changed it to a private function so that nobody would be tempted to
utilize it.

#require test-repo

Enable obsolescence to avoid the warning issue when obsmarker are found

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > evolution=createmarkers
  > EOF

Go back in the hg repo

  $ cd $TESTDIR/..

  $ for node in `hg log --rev 'draft() and ::.' --template '{node|short}\n'`; do
  >    hg export $node | contrib/check-commit > ${TESTTMP}/check-commit.out
  >    if [ $? -ne 0 ]; then
  >        echo "Revision $node does not comply to rules"
  >        echo '------------------------------------------------------'
  >        cat ${TESTTMP}/check-commit.out
  >        echo
  >   fi
  > done