[doc] Clarify that Popen.wait is only a busy-loop in certain cases

Documentation

In the docs for Popen.wait(), it states:

Note The function is implemented using a busy loop (non-blocking call and short sleeps). Use the asyncio module for an asynchronous wait: see asyncio.create_subprocess_exec.

This is actually only true in a specific circumstance: when both using Posix/Unix and a timeout is given. If, on the other hand, no timeout is given, then it does not go into a busy-loop but instead blocks on os.waitpid(). And for Windows, it never goes into a busy-loop, as it uses the WaitForSingleObject() windows API.

This note in the docs caused me to refactor my code to use asyncio - only later did I actually check what python did internally and discovered the note was wrong.

issueでリンクされているPopen.wait()のドキュメントから始め、ここで説明されているプラットフォームおよびtimeoutの挙動と注記を比較してください。注記を改訂し、busy-loopに関する主張をtimeout付きのPOSIX/Unixの待機に限定するとともに、timeoutなしの場合とWindowsの場合も正確に扱ってください。完了条件は、文言が技術的に正確で、asyncioに関する案内を維持していることです。