More precisely, if, for some reason, someone uses tokenizer.to_disk(path) as follows:

from spacy.util import get_lang_class
from tempfile import TemporaryDirectory
from pathlib import Path

tokenizer = get_lang_class("xx").Defaults.create_tokenizer()

with TemporaryDirectory() as temp_dir:
    tokenizer.to_disk(Path(temp_dir))

a PermissionError is raised, whereas

with TemporaryDirectory() as temp_dir:
    tokenizer.to_diks(Path(temp_dir) / "tokenizer.json")

works.

Judging from from this and the source code, path is opened as if it was a file.
The documentation of tokenizer.to_disk, however, describes it to require a path to a directory as argument. This seems to be inconsistent with its actual behaviour.

Your Environment

• spaCy version: 2.2.4
• Platform: Windows-10-10.0.18362-SP0
• Python version: 3.7.7
• Environment Information:
  • conda version: 4.8.3
  • conda-build version: 3.18.11