Urllib3: Broken import for HTTPHeaderDict in 1.26.0

[markstory]

Subject

Responses has historically used from urllib3.connection import HTTPHeaderDict but that import is now failing in 1.26.0. Looking through the history this was changed as part of #2018

This change wasn't in the release notes and seems like an accidental regression. Is there a more stable package we should be importing HTTPHeaderDict from?

Environment

Describe your environment.

• Using responses and urllib>=1.25.10

Steps to Reproduce

from urllib3.connection import HTTPHeaderDict

Expected Behavior

This import has worked for at least the past year.

Actual Behavior

An import error is raised.

Refs getsentry/responses#354

[sigmavirus24]

Is there a more stable package we should be importing HTTPHeaderDict from?

This passive aggressive tact is unnecessary.

[sethmlarson]

HTTPHeaderDict isn't supposed to be a public class (hence being defined in _collections). The import of HTTPHeaderDict in urllib3.response is likely more stable but there aren't any guarantees there either.

[sethmlarson]

I've opened https://github.com/urllib3/urllib3/pull/2046 against 1.26 to relieve your users pain over this issue, however this import will not work in v2.

[sethmlarson]

Will be released in v1.26.1

[markstory]

This passive aggressive tact is unnecessary.

I'm sorry. That was not my intent, I will try to be more direct in the future.

... however this import will not work in v2.
@sethmlarson In responses, we use this class when creating stubbed HTTP responses as it makes handling cookies easier. Will there be a different path to achieve that?