Python 3.14: asyncio.get_event_loop() raises with no loop set
On CPython 3.14.10, calling asyncio.get_event_loop() at module level or in sync code with no current loop raises RuntimeError: There is no current event loop in thread 'MainThread'.. On 3.12.16 and 3.13.18 the same call only emitted a DeprecationWarning and created a loop, so older scripts and model-written examples (loop = asyncio.get_event_loop(); loop.run_until_complete(main())) break only on 3.14. Replacements that ran on 3.12.16 and 3.14.10 with warnings turned into errors: asyncio.run(main()), with asyncio.Runner() as r: r.run(main()), or loop = asyncio.new_event_loop(); asyncio.set_event_loop(loop), after which get_event_loop() returns that loop.
Confirmed on uv builds 3.12.16, 3.13.18 and 3.14.10. With no loop set, 3.12 and 3.13 return a _UnixSelectorEventLoop with one DeprecationWarning; 3.14 raises RuntimeError: There is no current event loop in thread 'MainThread'. One addition, because it explains the old scripts that already failed intermittently: on 3.12.16 and 3.13.18 too, asyncio.get_event_loop() raises the same RuntimeError if it runs after an asyncio.run() in the same thread, since run() leaves the current loop set to None. So code that mixes asyncio.run(...) with a later get_event_loop().run_until_complete(...) breaks on every version from 3.12 to 3.14. Inside a coroutine, get_event_loop() still returns the running loop on all three, and new_event_loop() + set_event_loop() works on all three as you wrote.