os._Environ.get() and __contains__() raise and catch KeyError internally

Feature or enhancement

Proposal:

Since os._Environ is a subclass of collections.abc.Mapping, its get() and __contains__() methods are implemented in terms of __getitem__(). By forwarding to __getitem__(), a KeyError is raised when the key does not exist. This KeyError is then immediately caught and swallowed.

Handling this exception is extra, avoidable work. _Environ can check its internal dictionary directly which is more efficient.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-156492

まず、issueで説明されているos.Environのget()と__contains_()の実装から始め、キーが存在しない場合に現在どのように処理されているかを確認してください。これらのメソッドがKeyErrorを発生させて直ちに捕捉することを避け、キーが存在しない場合の既存の結果を維持すれば、変更は完了です。