`HTTPErrorProcessor` uses deprecated members of `addinfourl`/`HTTPResponse`

https://github.com/python/cpython/blob/0181aa2e3efedc6504b27f6fe74f096e5e454286/Lib/urllib/request.py#L625

Per the docs for urllib.response.addinfourl and http.client.HTTPResponse, response.code and response.info() are deprecated as of Python 3.9. This is an issue when writing handlers that generate their own response objects—these objects must continue to provide the deprecated members.

I admit I don’t know how common or advisable this use case is, but it happened to me while I was implementing HTTP caching. When serving a response from the cache, I didn’t have a “real” response object to modify, and I wasn’t confident that I could instantiate the right thing from the standard library (the docs call it “a http.client.HTTPResponse object slightly modified”).

Instead, I made my own class that implemented just enough of the interface to get by. I thought that headers, status, url, and I/O read operations would suffice… but then I realised that HTTPErrorProcessor runs after all other handlers (including mine). So I would also need to add the deprecated members in order to be compatible.

See also #86203, where (if I’m reading correctly) it’s request objects that need to continue to provide deprecated members in order to work with the standard library.

Linked PRs

• gh-123509
• gh-123541
• gh-132644
• gh-132670

issue でリンクされている HTTPErrorProcessor の実装について、Lib/urllib/request.py を読み、response.code と response.info() の使用に注目してください。開始する前にリンクされている PRs を確認し、そのうえで、生成される response オブジェクトがこれらの非推奨メンバーをもはや必要としないことを確認しつつ、ハンドラーの動作を維持してください。