fix: read-idle timeout on SSE so a stalled stream can't hang events()

[wei-hai]

Found running a real >10-minute job against prod: the SSE stream went silent at ~3 min (no frames, no keepalive, no close — a "zombie" connection), and job.events() hung — still blocked minutes after the job had already completed. poll/wait/run were unaffected (the job itself finished fine).

Root cause

ComfyLow.get_job_events (sync + async) opened the SSE stream with timeout=None, which disables httpx's read timeout — so iter_lines() blocks forever on a stalled-but-open connection. The high-level Job.events() reconnect/poll-fallback only runs when the stream ends (the generator returns or raises), which never happens for a zombie → events() hangs.

Fix

Give get_job_events a read-idle timeout (_SSE_IDLE_TIMEOUT, well above the server's keepalive interval) by default. A stalled stream now raises httpx.ReadTimeout, which Job.events() already catches and turns into a poll (terminal?) / reconnect. timeout=None still available to opt out.

Tests

Added a threaded stub stall mode (sends a couple frames, then holds the socket open and silent) and a regression test asserting events() recovers via the poll fallback in ~0.3s instead of waiting for close / hanging. Full suite: 74 passed; ruff/format/mypy/hygiene clean.

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• tests/test_sse_idle.py

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📝 Walkthrough

Walkthrough

Changes

SSE idle-timeout recovery

Layer / File(s)	Summary
SSE timeout integration src/comfy_low/transport.py	Sync and async get_job_events methods now apply _SSE_IDLE_TIMEOUT by default, while timeout=None remains an explicit opt-out.
Stalled SSE fixture tests/conftest.py	The threaded test server supports stalled SSE connections that emit non-terminal frames and delay before returning.
Recovery regression test tests/test_sse_idle.py	The test verifies timeout-driven recovery, progress delivery, successful terminal status, and bounded completion time.

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
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Inline comments:
In `@tests/test_sse_idle.py`:
- Around line 19-39: Extend test_events_recovers_from_zombie_stream coverage to
verify the async get_job_events path also recovers from a stalled SSE stream and
reaches the terminal StatusChange without hanging. Add a case using timeout=None
to confirm the explicit no-timeout contract, while preserving the existing
default-timeout recovery assertion and terminal-status checks.

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ℹ️ Review info

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Configuration used: Organization UI

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Run ID: a37df146-b945-4f32-a970-4e49905d5d6c

📥 Commits

Reviewing files that changed from the base of the PR and between e53affd and 157765b.

📒 Files selected for processing (3)

• src/comfy_low/transport.py
• tests/conftest.py
• tests/test_sse_idle.py