Fix unbound stream variable in DHT provider_store.py

[TimSC]

Fixes #1335

What was wrong?

When host.new_stream fails before a stream is opened, _send_add_provider hit an unbound stream in finally, masking the real error:

Error sending ADD_PROVIDER to <peer>: cannot access local variable 'stream' where it is not associated with a value

How was it fixed?

Initialize stream = None and only close when a stream was opened.

Test plan

• Unit test: new_stream failure returns False without UnboundLocalError
• make pr
• make linux-docs

Cute Animal Picture

[acul71]

Hi @TimSC — thank you for opening #1313 and for the clear diagnosis of the ADD_PROVIDER / unbound stream bug. The fix (stream = None plus guarded close in _send_add_provider) was already correct; we pushed a follow-up commit to your provider_store branch so the PR meets the usual libp2p merge requirements.

What was added

• Tracking issue: #1335 — documents the failure mode when new_stream errors before a stream is opened.
• Newsfragment: newsfragments/1335.bugfix.rst — user-facing release note for towncrier.
• Regression test: test_send_add_provider_new_stream_failure in tests/core/kad_dht/test_unit_provider_store.py — mocks new_stream raising and asserts _send_add_provider returns False without a secondary UnboundLocalError.
• PR description: updated with Fixes #1335 and a completed test plan checklist.
• Validation: make pr and make linux-docs both passed locally before push.

Branch

Latest commit on TimSC:provider_store: b452e978 — Add issue, newsfragment, and test for ADD_PROVIDER stream cleanup.

No further changes to your core fix in libp2p/kad_dht/provider_store.py. From here the PR should be ready for maintainer review; happy to adjust anything if you’d like a different wording on the issue or newsfragment.

Thanks again for contributing to py-libp2p.