Fossil

  int vid;              /* Current version */
  int tid=0;            /* Target version - version we are changing to */
  Stmt q;
  int latestFlag;       /* --latest.  Pick the latest version if true */
  int nochangeFlag;     /* -n or --nochange.  Do a dry run */
  int verboseFlag;      /* -v or --verbose.  Output extra information */
  int debugFlag;        /* --debug option */
  int setmtimeFlag;     /* --setmtime.  Set mtimes on files */
  int nChng;            /* Number of file renames */
  int *aChng;           /* Array of file renames */
  int i;                /* Loop counter */
  int nConflict = 0;    /* Number of merge conflicts */
  Stmt mtimeXfer;       /* Statment to transfer mtimes */

  if( !internalUpdate ){
    undo_capture_command_line();
    url_proxy_options();
  }
  latestFlag = find_option("latest",0, 0)!=0;
  nochangeFlag = find_option("nochange","n",0)!=0;
  verboseFlag = find_option("verbose","v",0)!=0;
  debugFlag = find_option("debug",0,0)!=0;
  setmtimeFlag = find_option("setmtime",0,0)!=0;
  db_must_be_within_tree();
  vid = db_lget_int("checkout", 0);
  if( vid==0 ){
    fossil_fatal("cannot find current version");
  }
  if( !nochangeFlag && db_exists("SELECT 1 FROM vmerge") ){
    fossil_fatal("cannot update an uncommitted merge");

  }

  if( tid==0 ){
    fossil_panic("Internal Error: unable to find a version to update to.");
  }

  db_begin_transaction();
  vfile_check_signature(vid, CKSIG_ENOTFILE);
  if( !nochangeFlag && !internalUpdate ) undo_begin();
  load_vfile_from_rid(tid);

  /*
  ** The record.fn field is used to match files against each other.  The
  ** FV table contains one row for each each unique filename in
  ** in the current checkout, the pivot, and the version being merged.

      db_lset_int("checkout", tid);
    }else{
      /* A subset of files have been checked out.  Keep the current
      ** checkout unchanged. */
      db_multi_exec("DELETE FROM vfile WHERE vid!=%d", vid);
    }
    if( !internalUpdate ) undo_finish();
    if( setmtimeFlag ) vfile_check_signature(vid, CKSIG_SETMTIME);
    db_end_transaction(0);
  }
}

/*
** Make sure empty directories are created
*/

      file_tree_name(zFile, &fname, 1);
      db_multi_exec("REPLACE INTO torevert VALUES(%B)", &fname);
      blob_reset(&fname);
    }
  }else{
    int vid;
    vid = db_lget_int("checkout", 0);
    vfile_check_signature(vid, 0);
    db_multi_exec(
      "DELETE FROM vmerge;"
      "INSERT INTO torevert "
      "SELECT pathname"
      "  FROM vfile "
      " WHERE chnged OR deleted OR rid=0 OR pathname!=origname;"
    );