Fix process crash. Remove hack to detect broken pipe behavior on linux < 2.6.11

[twisted-trac]

	@morotti reported
Trac ID	trac#9636
Type	defect
Created	2019-05-06 20:49:32Z

kernel 2.6.11 was deprecated a long time ago. For reference, there were the last OS using it:

• Debian 3 - 2005-2008
• RHEL 4 - 2005-2011

detectLinuxBrokenPipeBehavior() instantiates a pipe during import (twisted.internet.process) and calls select() to detect whether it is writeable.

This hack was meant to detect broken pipe behavior on linux < 2.6.11. select() is itself broken (including on recent kernels), crashing the python interpreter when there are more than 1024 opened file descriptors for the process.

This effectively causes applications attempting to (lazily) import twisted to crash -if 1024 file/socket are opened-.

Given the comments, it was known that this workaround was broken at the time it was made. Had to pick the lesser evil between the two kernel issues, broken pipe or broken select(). This should be removed since pipes were fixed, but select was not.

Searchable metadata

trac-id__9636 9636
type__defect defect
reporter__morotti morotti
priority__normal normal
milestone__None None
branch__ 
branch_author__ 
status__closed closed
resolution__fixed fixed
component__core core
keywords__None None
time__1557175772812833 1557175772812833
changetime__1557287213057888 1557287213057888
version__None None
owner__hawkowl hawkowl

[twisted-trac]

	@morotti commented

pull request: #1135

[twisted-trac]

	@hawkowl set owner to @hawkowl

LGTM.

[twisted-trac]

	@hawkowl set status to closed

In changeset 046a9b3

#!CommitTicketReference repository="" revision="046a9b3017d58b66b6f62239e734922f4edbc862"
Merge 9636-morotti-selectpatch: Remove hack to detect broken pipe behavior on linux < 2.6.11

Author: morotti
Reviewer: hawkowl
Fixes: ticket:9636