Support h2 ≥ 4

[twisted-trac]

	@Gallaecio reported
Trac ID	trac#10182
Type	enhancement
Created	2021-04-22 16:41:12Z

At the moment Twisted[http2] limits h2 >= 3.0, < 4.0.

In the [https://github.com/python-hyper/h2/blob/master/CHANGELOG.rst#7609-2020-09-19 h2 4.0.0 changelog] I only see 1 change that may prevent simply changing the current Twisted requirements: “Receiving DATA before HEADERS now raises a ProtocolError”. I’m not familiar enough with Twisted and h2 to tell whether or not it will require changes in Twisted.

Also, while I’m personally only interested in 4.0+ support, I wonder if the current lower limit makes any sense. Given the pull request that set that lower limit, it could probably be brought back down to 2.6.0.

I also wonder if the upper-limit for h2 versions should be removed (i.e. use just h2 >= 2.6.0). I imagine this was done to prevent the installation of a future, incompatible version of h2. But it does not seem to be the rule with most Twisted dependencies, and working around such a limit seems significantly harder (fork Twisted to support h2>=4 and install from fork?) than working around the issues that may arise from not having it (cap h2 to <4 in your project).

The current h2 version limit prevents Twisted http2 installation with Conda when using Python 3.9.

Searchable metadata

trac-id__10182 10182
type__enhancement enhancement
reporter__Gallaecio Gallaecio
priority__normal normal
milestone__None None
branch__ 
branch_author__ 
status__closed closed
resolution__fixed fixed
component__web web
keywords__None None
time__1619109672291569 1619109672291569
changetime__1653891428989334 1653891428989334
version__None None
owner__None None

[twisted-trac]

	@twm set status to closed

Fixed in #1698 this past March