PathNode *path_midpoint(void){
  PathNode *p;
  int i;
  if( path.nStep<2 ) return 0;
  for(p=path.pEnd, i=0; p && i<path.nStep/2; p=p->pFrom, i++){}
  return p;
}

/*
** Compute the shortest path between two check-ins and then transfer
** that path into the "ancestor" table.  This is a utility used by
** both /annotate and /finfo.  See also: compute_direct_ancestors().
*/
void path_shortest_stored_in_ancestor_table(
  int origid,     /* RID for check-in at start of the path */
  int cid         /* RID for check-in at the end of the path */
){
  PathNode *pPath;
  Blob sql;
  int gen = 0;
  char *zSep = "VALUES";
  pPath = path_shortest(cid, origid, 1, 0);
  db_multi_exec(
    "CREATE TEMP TABLE IF NOT EXISTS ancestor("
    "  rid INT UNIQUE,"
    "  generation INTEGER PRIMARY KEY"
    ");"
    "DELETE FROM ancestor;"
  );
  blob_init(&sql, "INSERT INTO ancestor(rid, generation)", -1);
  while( pPath ){
    blob_append_sql(&sql, "%s(%d,%d)", zSep/*safe-for-%s*/, pPath->rid,++gen);
    zSep = ",";
    pPath = pPath->u.pTo;
  }
  path_reset();
  db_multi_exec("%s", blob_sql_text(&sql));
  blob_reset(&sql);
}

/*
** COMMAND: test-shortest-path
**
** Usage: %fossil test-shortest-path ?--no-merge? VERSION1 VERSION2
**
** Report the shortest path between two check-ins.  If the --no-merge flag