Fossil

    **    (2)  Merge parents
    **    (3)  Cherrypick merge parents.
    **    (4)  All ancestores of 1 and 2 but not of 3.
    */
    double rLimitMtime = 0.0;
    if( ridBackTo ){
      rLimitMtime = db_double(0.0,
         "SELECT mtime FROM event WHERE objid=%d",


         ridBackTo);
    }
    db_multi_exec(
      "WITH RECURSIVE "
      "  parent(pid,cid,isCP) AS ("
      "    SELECT plink.pid, plink.cid, 0 AS xisCP FROM plink"
      "    UNION ALL"
      "    SELECT parentid, childid, 1 FROM cherrypick WHERE NOT isExclude"
      "  ),"
      "  ancestor(rid, mtime, isCP) AS ("
      "    SELECT %d, mtime, 0 FROM event WHERE objid=%d "
      "    UNION "
      "    SELECT parent.pid, event.mtime, parent.isCP"
      "      FROM ancestor, parent, event"
      "     WHERE parent.cid=ancestor.rid"
      "       AND event.objid=parent.pid"
      "       AND NOT ancestor.isCP"
      "       AND (event.mtime>=%.17g OR parent.pid=%d)"
      "     ORDER BY mtime DESC LIMIT %d"
      "  )"
      "INSERT OR IGNORE INTO ok"
      "  SELECT rid FROM ancestor;",
      rid, rid, rLimitMtime, ridBackTo, N
    );
    if( ridBackTo && db_changes()>1 ){
      db_multi_exec("INSERT OR IGNORE INTO ok VALUES(%d)", ridBackTo);
    }
  }
}

/*
** Compute the youngest ancestor of record ID rid that is a member of
** branch zBranch.
*/