visualize polyglot book on board is not expected

[sugizo]

code

import chess
import chess.polyglot
from IPython.display import display, HTML, clear_output

def open_book(default_book, visual = "svg"):
    book = input("Polyglot Book : ") or default_book

    board = chess.Board()

    with chess.polyglot.open_reader(book) as reader:
        header = """
        <table>
        <tr>
        <th style = "text-align: center">Key</th>
        <th style = "text-align: center">Move</th>
        <th style = "text-align: center">Raw Move</th>
        <th style = "text-align: center">Weight</th>
        <th style = "text-align: center">Learn</th>
        </tr>
        """
        footer = "</table>"

        list_moves = []
        for entry in reader.find_all(board):
            list_moves.append(entry.move)
            content_list_html.append("""
            <tr>
            <td style = "text-align: center">%s</td>
            <td style = "text-align: center">%s</td>
            <td style = "text-align: center">%s</td>
            <td style = "text-align: center">%s</td>
            <td style = "text-align: center">%s</td>
            </tr>
            """ % (entry.key, entry.move, entry.raw_move, entry.weight, entry.learn) )

    content = "".join(content_list_html)
    html_book = header + content + footer

    display(HTML(html_book) )

    for uci in list_moves:
        board.push(uci)

    display(board)

open_book("polyglot/performance.bin")

result not expected

expected result
the pawn on d4 should be white

question
where is the root cause of that problem :
my code
or
the board.push during reading gaviota *.bin ?

best regards

[niklasf]

The code pushes e2e4, d2d4 and c2c4, but after 1. e4 it is now black to move, and pushing 1. d4 is therefore invalid.

For performance in board.push()

Moves are not checked for legality. It is the caller’s responsibility to ensure that the move is at least pseudo-legal or a null move.

Instead it breaks in the weird way that you see.