always requiring the username in the dataset name when there is one
{'login': 'stas00', 'id': 10676103, 'node_id': 'MDQ6VXNlcjEwNjc2MTAz', 'avatar_url': 'https://avatars.githubusercontent.com/u/10676103?v=4', 'gravatar_id': '', 'url': 'https://api.github.com/users/stas00', 'html_url': 'https://github.com/stas00', 'followers_url': 'https://api.github.com/users/stas00/followers', 'following_url': 'https://api.github.com/users/stas00/following{/other_user}', 'gists_url': 'https://api.github.com/users/stas00/gists{/gist_id}', 'starred_url': 'https://api.github.com/users/stas00/starred{/owner}{/repo}', 'subscriptions_url': 'https://api.github.com/users/stas00/subscriptions', 'organizations_url': 'https://api.github.com/users/stas00/orgs', 'repos_url': 'https://api.github.com/users/stas00/repos', 'events_url': 'https://api.github.com/users/stas00/events{/privacy}', 'received_events_url': 'https://api.github.com/users/stas00/received_events', 'type': 'User', 'site_admin': False}
[{'id': 1935892871, 'node_id': 'MDU6TGFiZWwxOTM1ODkyODcx', 'url': 'https://api.github.com/repos/huggingface/datasets/labels/enhancement', 'name': 'enhancement', 'color': 'a2eeef', 'default': True, 'description': 'New feature or request'}]
{'login': 'lhoestq', 'id': 42851186, 'node_id': 'MDQ6VXNlcjQyODUxMTg2', 'avatar_url': 'https://avatars.githubusercontent.com/u/42851186?v=4', 'gravatar_id': '', 'url': 'https://api.github.com/users/lhoestq', 'html_url': 'https://github.com/lhoestq', 'followers_url': 'https://api.github.com/users/lhoestq/followers', 'following_url': 'https://api.github.com/users/lhoestq/following{/other_user}', 'gists_url': 'https://api.github.com/users/lhoestq/gists{/gist_id}', 'starred_url': 'https://api.github.com/users/lhoestq/starred{/owner}{/repo}', 'subscriptions_url': 'https://api.github.com/users/lhoestq/subscriptions', 'organizations_url': 'https://api.github.com/users/lhoestq/orgs', 'repos_url': 'https://api.github.com/users/lhoestq/repos', 'events_url': 'https://api.github.com/users/lhoestq/events{/privacy}', 'received_events_url': 'https://api.github.com/users/lhoestq/received_events', 'type': 'User', 'site_admin': False}
[{'login': 'lhoestq', 'id': 42851186, 'node_id': 'MDQ6VXNlcjQyODUxMTg2', 'avatar_url': 'https://avatars.githubusercontent.com/u/42851186?v=4', 'gravatar_id': '', 'url': 'https://api.github.com/users/lhoestq', 'html_url': 'https://github.com/lhoestq', 'followers_url': 'https://api.github.com/users/lhoestq/followers', 'following_url': 'https://api.github.com/users/lhoestq/following{/other_user}', 'gists_url': 'https://api.github.com/users/lhoestq/gists{/gist_id}', 'starred_url': 'https://api.github.com/users/lhoestq/starred{/owner}{/repo}', 'subscriptions_url': 'https://api.github.com/users/lhoestq/subscriptions', 'organizations_url': 'https://api.github.com/users/lhoestq/orgs', 'repos_url': 'https://api.github.com/users/lhoestq/repos', 'events_url': 'https://api.github.com/users/lhoestq/events{/privacy}', 'received_events_url': 'https://api.github.com/users/lhoestq/received_events', 'type': 'User', 'site_admin': False}]
From what I can understand, you want the saved arrow file directory to have username as well instead of just dataset name if it was downloaded with the user prefix? I don't think the user cares of how this is done, but the 2nd command should fail, IMHO, as its dataset name is invalid:
```
# first run
python -c "from datasets import load_dataset; load_dataset('stas/openwebtext-10k')"
# now run immediately
python -c "from datasets import load_dataset; load_dataset('openwebtext-10k')"
# the second command should fail, but it doesn't fail now.
```

Moreover, if someone were to create `openwebtext-10k` w/o the prefix, they will now get the wrong dataset, if they previously downloaded `stas/openwebtext-10k`.

And if there are 2 users with the same dataset name `foo/ds` and `bar/ds` - currently this won't work to get the correct dataset.

So really there 3 unrelated issues hiding in the current behavior. This has been fixed now, and we'll do a new release of the library today.

Now the stas/openwebtext-10k dataset is cached at `.cache/huggingface/datasets/stas___openwebtext10k` and openwebtext-10k would be at `.cache/huggingface/datasets/openwebtext10k`. Since they are different, the cache won't fall back on loading the wrong one anymore.

Same for the python script used to generate the dataset: stas/openwebtext-10k is cached at `.cache/huggingface/modules/datasets_modules/datasets/stas___openwebtext10k` and openwebtext-10k would be at `.cache/huggingface/modules/datasets_modules/datasets/openwebtext10k` Amazing! Thank you for adding this improvement, @lhoestq! (can be closed?) Yes indeed :) thanks
Me and now another person have been bitten by the `datasets`'s non-strictness on requiring a dataset creator's username when it's due.

So both of us started with `stas/openwebtext-10k`, somewhere along the lines lost `stas/` and continued using `openwebtext-10k` and it all was good until we published the software and things broke, since there is no `openwebtext-10k`

So this feature request is asking to tighten the checking and not allow dataset loading if it was downloaded with the user prefix, but then attempted to be used w/o it.

The same in code:

```
# first run
python -c "from datasets import load_dataset; load_dataset('stas/openwebtext-10k')"
# now run immediately
python -c "from datasets import load_dataset; load_dataset('openwebtext-10k')"
# the second command should fail, but it doesn't fail now.
```

Please let me know if I explained myself clearly.

Thank you!
{'url': 'https://api.github.com/repos/huggingface/datasets/issues/2842/reactions', 'total_count': 1, '+1': 1, '-1': 0, 'laugh': 0, 'hooray': 0, 'confused': 0, 'heart': 0, 'rocket': 0, 'eyes': 0}