* fix(studio/colab): survive ipykernel OutStream close() during startup
Unsloth Studio crashed at server startup on Colab with:
Unsloth Studio failed to start: 'OutStream' object has no attribute
'watch_fd_thread'
Root cause:
- Colab's ipykernel OutStream is created with watchfd=False, so it never
gains a watch_fd_thread. The OutStream.close() in the affected ipykernel
versions joins that thread unconditionally and raises AttributeError
(ipython/ipykernel#867).
- _setup_server_disk_logging() replaces sys.stdout/sys.stderr with a tee.
That changes the console object identity, so Colab's absl logging handler
(which captured the original OutStream and whose close() deliberately skips
sys.stdout/sys.stderr) no longer treats it as the live console.
- run_server builds uvicorn.Config(...), whose configure_logging runs
logging.config.dictConfig -> logging.shutdown, closing every existing
handler. The absl handler then calls close() on the orphaned OutStream and
the AttributeError propagates out of uvicorn.Config and aborts startup.
Fix:
- Before installing the tee, harden the displaced console streams' close() so
only the ipykernel#867 AttributeError is swallowed; a healthy close() runs
unchanged and any other error still propagates. The buggy close() raises
before it nulls pub_thread, so the stream stays fully usable.
- Give _TeeStream its own close() that flushes the log copy and forwards
close() to the wrapped console stream best-effort, so a handler that
captured the tee cannot crash startup either.
Add regression tests reproducing the exact path (an absl-style handler closing
a watchfd=False OutStream stand-in during logging.shutdown) and asserting the
tee/console path survives and keeps logging.
* [pre-commit.ci] auto fixes from pre-commit.com hooks
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* Show the Colab login password in the shareable link card
* Tighten Colab card comments for PR #7404
* [pre-commit.ci] auto fixes from pre-commit.com hooks
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* Make the Colab tunnel URL clickable and emphasise the password
* [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
* Narrow the console close() hardening to the watch_fd_thread AttributeError
* Put the Colab password on its own line so selection excludes the label
* Keep the Colab password as plain selectable text
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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
