Open() on path that exceeds 248 char limit results in "FileNotFoundError: [Errno 2] No such file or directory"

Bug report

Attempting to open or appending paths to sys.path with paths that length exceed the 248 character limit results in incorrect errors. In the case of opening paths that exceeded the limit, rather than an error pointing to the path length being exceeded we see a file not found. A similar error handling issue is prevalent with appending paths that exceed the limit to sys.path. In this case when trying to access the module you will receive a module not found error. I am now aware the path limit can be disabled on installation or later but these false flags led me astray while debugging.

Reproduction Steps:

• Create a text file whose path exceeds 248 characters
• Attempt to read/write from that file
  or
• Create a Python module whose path exceeds 248 characters
• Attempt to import that module from an external directory by appending the path to sys.path

Environment

• CPython versions tested on: 3.10.4
• Operating system and architecture: Windows x64

まず、Windows x64 上の Python 3.10.4 で報告された挙動を再現します。パスが 248 文字を超えるファイルを開き、その後、sys.path に追加した長すぎるパスからモジュールをインポートしてテストします。open と import の失敗を追跡し、長さの条件が失われる箇所を特定します。両方のケースで、FileNotFoundError や ModuleNotFoundError ではなく、パス長に関する正確なエラーが報告されれば完了です。