Do not recurse when getting the metadata of an NWB file in a BIDS dataset

[CodyCBakerPhD]

Problem

For an NWB file in a BIDS dataset, dandi.metadata.nwb.get_metadata() took the BIDS part of the metadata from df.get_metadata(). df is an NWBBIDSAsset, and its get_metadata() also extracts the NWB metadata, via NWBAsset.get_metadata() → nwb2asset() → get_metadata(). That calls back into the same BIDS branch, so the cycle repeats until RecursionError.

The result was still correct, because NWBAsset.get_metadata() falls back to default metadata on errors at each level. But the BIDS validator ran at every one of roughly 100 levels. On ieeg_epilepsyNWB from bids-examples, one get_metadata() call made 98 nested nwb2asset() calls and took about 60 s. That is what made test_bids_nwb_metadata_integration time out on Windows CI.

Fix

Take only the BIDS metadata, via bids.BIDSAsset.get_metadata(df, ...), which was the intent of that branch. The NWB metadata is extracted by the rest of get_metadata() itself.

Measured on the same file:

	nwb2asset() calls	time	subject_id / sex
before	98 (nested)	60.9 s	01 / U
after	0	0.7 s	01 / U

Tests

• Added test_bids_nwb_metadata_no_recursion, which spies on nwb2asset(). It fails on the current master (68 calls) and passes with the fix.
• dandi/tests/test_metadata.py, dandi/tests/test_files.py, dandi/files and dandi/validate/tests/test_core.py pass locally: 198 passed.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Qn5WBSiQgoZoL4fytF6nEr

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Generated by Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.80%. Comparing base (ad8f64d) to head (e38507b).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1958      +/-   ##
==========================================
+ Coverage   90.77%   90.80%   +0.03%     
==========================================
  Files          92       92              
  Lines       14130    14142      +12     
==========================================
+ Hits        12826    12842      +16     
+ Misses       1304     1300       -4     

Flag	Coverage Δ
unittests	90.80% <100.00%> (+0.03%)	⬆️

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