bf: pass aiohttp timeouts to fsspec to fix test hang

[yarikoptic]

Summary

Fix the indefinite hang in test_nwb2asset_remote_asset that has been blocking dandi-archive CLI integration tests since November 24, 2025.

Root cause

RemoteReadableAsset.open() calls fsspec.open(url) with no socket-level timeouts. When h5py reads an NWB file through fsspec's HTTP backend, the call chain is:

nwb2asset() → get_metadata() → _get_pynwb_metadata()
  → open_readable() → RemoteReadableAsset.open()
    → fsspec.open(url).open()          # aiohttp, no timeout
      → h5py.File(fp) + NWBHDF5IO     # holds HDF5 global lock

This creates conditions for a deadlock documented in h5py/h5py#2019:

• h5py holds a global lock while reading from the Python file object
• fsspec's sync() blocks the calling thread in threading.Event.wait() waiting for the aiohttp coroutine
• aiohttp has no default socket timeout (ClientSession.request will hang forever in rare cases despite using ClientTimeout.total aio-libs/aiohttp#11740), so a stalled connection blocks forever
• GC running during this window can deadlock with h5py's lock

Why it surfaced on November 24

Analysis of tinuous CI logs for dandi-archive showed:

Date	dandi-cli	dandischema	test result
Nov 21	0.73.2+5 (8492260)	>= 0.11.1, < 0.12.0	XFAIL in 0.4s
Nov 24	0.73.2+11 (fa3ce1e)	~= 0.12.0	hung 6 hours

With dandischema 0.11.x, the test hit a quick model validation mismatch (XFAIL before reaching fsspec). PR #1744 updated to dandischema 0.12.0 (vendor-configurable models, schema 0.7.0), which fixed that mismatch — so the test now reaches the fsspec HTTP read, which hangs.

Additionally, dandi-cli's tox.ini global --timeout=300 is not read when tests run from the dandi-archive rootdir via pytest --pyargs dandi.

Changes

• a6109be bf: pass aiohttp timeouts to fsspec in RemoteReadableAsset.open()
  • Passes ClientTimeout(total=120, sock_read=60, sock_connect=30) so stalled connections raise TimeoutError instead of blocking forever
• 166324a bf(test): add timeout to test_nwb2asset_remote_asset to prevent CI hang
  • Adds @pytest.mark.timeout(120) as belt-and-suspenders (works regardless of rootdir config)

Companion change

dandi-archive cli-integration.yml will also add --timeout=300 to the pytest command line and remove the -k "not test_nwb2asset_remote_asset" exclusion — but that needs a new dandi-cli release containing these fixes for the release matrix variant to pick them up.

References

• Archive-CLI integration tests hanging forever #1762 — Archive-CLI integration tests hanging forever
• test_nwb2asset_remote_asset timed out in test (ubuntu-latest, 3.8, dandi-api) #1450 — test_nwb2asset_remote_asset timed out
• BytesCache use of .fetcher might lead to a stall if original coroutine stalls? fsspec/filesystem_spec#1666 — BytesCache fetcher stall
• Potential deadlock from some combination of h5py, gc, and fsspec h5py/h5py#2019 — Deadlock from h5py + GC + file-like objects
• ClientSession.request will hang forever in rare cases despite using ClientTimeout.total aio-libs/aiohttp#11740 — ClientSession hanging despite timeout

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.11%. Comparing base (a3dd9f9) to head (a6109be).
⚠️ Report is 10 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1795   +/-   ##
=======================================
  Coverage   75.11%   75.11%           
=======================================
  Files          84       84           
  Lines       11921    11923    +2     
=======================================
+ Hits         8954     8956    +2     
  Misses       2967     2967           

Flag	Coverage Δ
unittests	75.11% <100.00%> (+<0.01%)	⬆️

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[yarikoptic]

I will keep it to update and rerun after we merge other minor PRs and to release

[yarikoptic]

other PRs might need more time, let's proceed!

[github-actions]

🚀 PR was released in 0.74.3 🚀