`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

阅读 issue 中链接的 HTTPErrorProcessor 实现所在的 Lib/urllib/request.py，重点关注其对 response.code 和 response.info() 的使用。在开始之前检查链接的 PR，然后确认生成的 response 对象不再需要这些已弃用的成员，同时保持处理器的行为不变。