Cannot pause asyncio transport immediately

[LasseBlaauwbroek]

Bug report

When creating a asyncio transport/protocol pair, one might want to call transport.pause_reading() immediately when protocol.connection_made() is called. This is currently not possible. The call to pause_reading() is ignored, and reading commences nonetheless.

This is problematic, because there is no other place where the transport can be immediately paused, especially when the protocol is created through loop.create_server.

As a remedy, I would suggest guarding

cpython/Lib/asyncio/selector_events.py

Lines 931 to 932 in ece20db

	self._loop.call_soon(self._add_reader,
	self._sock_fd, self._read_ready)

with if not self._paused:. There might be other places where this is needed, for other event loops.

Linked PRs

• gh-103607: Fixing pause_reading called in connection made is ignored #17425
• [3.11] gh-103607: Fix pause_reading to work when called from connection_made in asyncio. (GH-17425) #103918

[gvanrossum]

@LasseBlaauwbroek This makes sense, could you make a PR (with tests, please)?

[arhadthedev]

gh-17425 is a PR from gh-76002 closed as a duplicate of this issue.