Title: Improve default patterns resolution
Author: mariosasko (COLLABORATOR)
State: closed
Created: 2024-03-01T16:31:25Z

Separate the default patterns that match directories from the ones matching files and ensure directories are checked first (reverts the change from https://github.com/huggingface/datasets/pull/6244, which merged these patterns). Also, ensure that the glob patterns do not overlap to avoid duplicates in the result. 

Additionally, replace `get_fs_token_paths` with `url_to_fs` to avoid [unnecessary glob calls](https://github.com/fsspec/filesystem_spec/blob/14dce8ca78f7aa509a20edb263bff83a7760c24d/fsspec/core.py#L655-L656).

fix https://github.com/huggingface/datasets/issues/6259
fix https://github.com/huggingface/datasets/issues/6272

Comments:
The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/datasets/pr_6704). All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

Awesome !

Note that it can still create duplicates if a path matches several dir patterns, e.g.

```
data/train-train/data/txt
```
matches two dir patterns:
```
**/{keyword}[{sep}]*/**
**/*[{sep}]{keyword}/**
```

PS: feel free to update your branch, I just updated ruff on `main`

Yes, I didn't mention that case on purpose 🙂. One solution would be deprecating the `**/*[{sep}]{keyword}/**` pattern (and eventually removing it). This way, the directory patterns would align more with the filename ones. Or do you think this is too big of a breaking change?

I think it's too big of a breaking change yes :/ (and would make the docs / logic more complex for users to get imo) Though I think your approach is already a nice step in the right direction

These changes to the `resolve_pattern` function lead to 20-30x faster local file resolution in my benchmarks.

Nice ! Though since `fsspec` caches the filesystem, is there a risk when adding new files and reloading a dataset ?


```python
with open("my/local/dir/0000.txt", "w") as f:
    f.write("Hello there")
d1 = load_dataset("my/local/dir")
with open("my/local/dir/0001.txt", "w") as f:
    f.write("General Kenobi")
d2 = load_dataset("my/local/dir")
assert list(d1) != list(d2)
```

Yes. But I think I have a solution for this.

I'm not satisfied with the context manager approach...

A clean solution would require a bigger rewrite of the resolution logic (e.g., merging `get_data_patterns` and `DataFilesDict.from_patterns` into a `get_data_files` function that would build the `DataFilesDict` by matching the paths using `fs.find` and `fsspec.utils.glob_translate` (available in `fsspec>=2023.12.0`))

The current changes make the local resolution 2-3x faster, which is good enough for now, I think.

<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.004888 / 0.011353 (-0.006465) | 0.003267 / 0.011008 (-0.007742) | 0.065117 / 0.038508 (0.026609) | 0.029416 / 0.023109 (0.006306) | 0.232021 / 0.275898 (-0.043877) | 0.258053 / 0.323480 (-0.065427) | 0.003971 / 0.007986 (-0.004014) | 0.002550 / 0.004328 (-0.001779) | 0.049126 / 0.004250 (0.044876) | 0.040620 / 0.037052 (0.003568) | 0.253437 / 0.258489 (-0.005052) | 0.273583 / 0.293841 (-0.020258) | 0.026775 / 0.128546 (-0.101771) | 0.010073 / 0.075646 (-0.065573) | 0.219089 / 0.419271 (-0.200183) | 0.035047 / 0.043533 (-0.008486) | 0.247661 / 0.255139 (-0.007478) | 0.258674 / 0.283200 (-0.024525) | 0.018428 / 0.141683 (-0.123255) | 1.130394 / 1.452155 (-0.321761) | 1.173167 / 1.492716 (-0.319549) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.092581 / 0.018006 (0.074574) | 0.303657 / 0.000490 (0.303167) | 0.000215 / 0.000200 (0.000015) | 0.000051 / 0.000054 (-0.000003) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.018640 / 0.037411 (-0.018771) | 0.062032 / 0.014526 (0.047506) | 0.073982 / 0.176557 (-0.102575) | 0.121499 / 0.737135 (-0.615636) | 0.076780 / 0.296338 (-0.219559) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.279411 / 0.215209 (0.064202) | 2.737977 / 2.077655 (0.660322) | 1.454135 / 1.504120 (-0.049985) | 1.343144 / 1.541195 (-0.198051) | 1.339876 / 1.468490 (-0.128614) | 0.567306 / 4.584777 (-4.017471) | 2.372569 / 3.745712 (-1.373143) | 2.716810 / 5.269862 (-2.553052) | 1.697895 / 4.565676 (-2.867782) | 0.061804 / 0.424275 (-0.362471) | 0.004986 / 0.007607 (-0.002622) | 0.332721 / 0.226044 (0.106676) | 3.274572 / 2.268929 (1.005644) | 1.789900 / 55.444624 (-53.654725) | 1.536346 / 6.876477 (-5.340131) | 1.551940 / 2.142072 (-0.590132) | 0.634539 / 4.805227 (-4.170688) | 0.115860 / 6.500664 (-6.384805) | 0.041737 / 0.075469 (-0.033732) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.024469 / 1.841788 (-0.817319) | 11.327496 / 8.074308 (3.253188) | 9.265855 / 10.191392 (-0.925537) | 0.142200 / 0.680424 (-0.538224) | 0.013945 / 0.534201 (-0.520256) | 0.289670 / 0.579283 (-0.289614) | 0.269240 / 0.434364 (-0.165124) | 0.324748 / 0.540337 (-0.215590) | 0.421393 / 1.386936 (-0.965543) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.005284 / 0.011353 (-0.006069) | 0.003351 / 0.011008 (-0.007658) | 0.049973 / 0.038508 (0.011465) | 0.030257 / 0.023109 (0.007148) | 0.273660 / 0.275898 (-0.002238) | 0.300328 / 0.323480 (-0.023152) | 0.004133 / 0.007986 (-0.003852) | 0.002614 / 0.004328 (-0.001715) | 0.048055 / 0.004250 (0.043804) | 0.044731 / 0.037052 (0.007678) | 0.290257 / 0.258489 (0.031768) | 0.321243 / 0.293841 (0.027402) | 0.029542 / 0.128546 (-0.099004) | 0.010074 / 0.075646 (-0.065573) | 0.057944 / 0.419271 (-0.361327) | 0.051267 / 0.043533 (0.007734) | 0.276278 / 0.255139 (0.021139) | 0.302464 / 0.283200 (0.019264) | 0.018231 / 0.141683 (-0.123452) | 1.140782 / 1.452155 (-0.311373) | 1.182991 / 1.492716 (-0.309725) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.092325 / 0.018006 (0.074319) | 0.302610 / 0.000490 (0.302121) | 0.000202 / 0.000200 (0.000002) | 0.000049 / 0.000054 (-0.000005) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.021458 / 0.037411 (-0.015954) | 0.074883 / 0.014526 (0.060357) | 0.085747 / 0.176557 (-0.090809) | 0.125506 / 0.737135 (-0.611629) | 0.086921 / 0.296338 (-0.209417) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.290485 / 0.215209 (0.075276) | 2.853898 / 2.077655 (0.776243) | 1.615606 / 1.504120 (0.111486) | 1.491797 / 1.541195 (-0.049397) | 1.515981 / 1.468490 (0.047491) | 0.566760 / 4.584777 (-4.018017) | 2.462593 / 3.745712 (-1.283119) | 2.765516 / 5.269862 (-2.504345) | 1.755078 / 4.565676 (-2.810598) | 0.063614 / 0.424275 (-0.360661) | 0.005040 / 0.007607 (-0.002567) | 0.347957 / 0.226044 (0.121912) | 3.464258 / 2.268929 (1.195330) | 1.992273 / 55.444624 (-53.452351) | 1.699147 / 6.876477 (-5.177330) | 1.868438 / 2.142072 (-0.273635) | 0.660756 / 4.805227 (-4.144471) | 0.118142 / 6.500664 (-6.382522) | 0.041974 / 0.075469 (-0.033495) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.012206 / 1.841788 (-0.829581) | 12.343735 / 8.074308 (4.269427) | 10.321975 / 10.191392 (0.130583) | 0.140007 / 0.680424 (-0.540417) | 0.015755 / 0.534201 (-0.518446) | 0.291978 / 0.579283 (-0.287305) | 0.278792 / 0.434364 (-0.155572) | 0.325366 / 0.540337 (-0.214972) | 0.439403 / 1.386936 (-0.947533) |

</details>
</details>

![](https://cml.dev/watermark.png#d1d3c06a651c6ad5142f331cb5dc0008ddcade33 "CML watermark")


This change is breaking in 

https://github.com/huggingface/datasets/blob/f96e74d5c633cd5435dd526adb4a74631eb05c43/src/datasets/arrow_dataset.py#L1515

when the input is `pathlib.Path`. The issue is that `url_to_fs` expects a `str` and cannot deal with `Path`. `get_fs_token_paths` converts to `str` so it is not a problem

I opened https://github.com/huggingface/datasets/pull/6828 to add proper Path support to save_to_disk / load_from_disk