Add public convert_to_bids method to BaseDataset for clean BIDS export

[Copilot]

BIDS conversion was only accessible via get_data(cache_config=...), coupling it to the caching system and embedding a processing-pipeline hash (desc-<hash>) in all filenames — unsuitable for producing shareable BIDS datasets.

Changes

• New BaseDataset.convert_to_bids(path=None, subjects=None, overwrite=False, verbose=None) method — the canonical public API for BIDS conversion
  • Saves raw EEG as BIDS-compliant EDF without desc-<hash> entities in filenames
  • Skips already-converted subjects when overwrite=False (checks for existing EDF files); erases and re-saves on overwrite=True
  • Does not write lock files (lock files are an internal detail of the caching mechanism only)
  • Returns the BIDS root Path
• Internal _BIDSInterfaceRawEDFNoDesc subclass — overrides desc → None, overrides _write_lock_file() as a no-op, and replaces erase() with shutil.rmtree on the subject directory
• BIDSInterfaceBase.save() refactored to extract lock file writing into a _write_lock_file() method, allowing subclasses to opt out
• BIDSInterfaceBase.__repr__ fixed to handle desc=None without a TypeError

Usage

from moabb.datasets import AlexMI

dataset = AlexMI()
bids_root = dataset.convert_to_bids(path="/data/bids", subjects=[1, 2])
# → /data/bids/MNE-BIDS-alexandre-motor-imagery/
# Files: sub-1_ses-0_task-imagery_run-0_eeg.edf  (no desc-hash, no lock files)

For pseudo-BIDS caching of epochs/arrays, get_data(cache_config=...) remains the appropriate path.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>BIDS conversion should be more public</issue_title>
<issue_description>At the moment, all the datasets can be easy convert to bids with the cache.

The main problem is the interface of the cache, the cache is design to be invisible, so the interface is not clear.

We need to one public function that convert the dataset to bids that don't write the description hash that it is linked with the cache logic.

Needs to be minimum interface.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes BIDS conversion should be more public #987

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[PierreGtch]

@bruAristimunha could we make convert_dataset_to_bids a method of BaseDataset?

[bruAristimunha]

@copilot, work on the last suggestion

[Copilot]

@copilot, work on the last suggestion

Done in a0ae65d. The BIDS conversion logic is now a convert_to_bids method on BaseDataset:

dataset = AlexMI()
bids_root = dataset.convert_to_bids(path='/data/bids', subjects=[1, 2])

The standalone convert_dataset_to_bids function in bids_interface.py now just delegates to this method.

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[bruAristimunha]

And the lock file @copilot? Should not exist within this function

[Copilot]

And the lock file @copilot? Should not exist within this function

Fixed in 9c58f2d. convert_to_bids no longer uses lock files:

• _BIDSInterfaceRawEDFNoDesc overrides _write_lock_file() to do nothing (so save() never writes one)
• The skip check now looks for existing EDF files (subject_dir.rglob("*.edf")) instead of checking for a lock file