Update libffi to 3.4.2

[zooba]

BPO	45022
Nosy	@pfmoore, @tjguk, @ned-deily, @ambv, @zware, @zooba, @pablogsal, @miss-islington, @Ghostkeeper
PRs	bpo-45022: Pin current libffi build to fixed version in preparation for upcoming update #27982 [3.10] bpo-45022: Pin current libffi build to fixed version in preparation for upcoming update (GH-27982) #27984 [3.9] bpo-45022: Pin current libffi build to fixed version in preparation for upcoming update (GH-27982) #27985 [3.8] bpo-45022: Pin current libffi build to fixed version in preparation for upcoming update (GH-27982) #28001 bpo-45022: Update libffi to 3.4.2 in Windows build #28146

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-09-09.21:03:07.969>
created_at = <Date 2021-08-26.21:13:17.382>
labels = ['type-bug', '3.9', '3.10', '3.11', 'ctypes', 'build', 'OS-windows']
title = 'Update libffi to 3.4.2'
updated_at = <Date 2021-09-13.14:45:40.034>
user = 'https://github.com/zooba'

bugs.python.org fields:

activity = <Date 2021-09-13.14:45:40.034>
actor = 'zach.ware'
assignee = 'none'
closed = True
closed_date = <Date 2021-09-09.21:03:07.969>
closer = 'steve.dower'
components = ['Build', 'Windows', 'ctypes']
creation = <Date 2021-08-26.21:13:17.382>
creator = 'steve.dower'
dependencies = []
files = []
hgrepos = []
issue_num = 45022
keywords = ['patch']
message_count = 13.0
messages = ['400382', '400383', '400385', '400430', '400431', '400432', '401004', '401012', '401013', '401330', '401518', '401696', '401704']
nosy_count = 9.0
nosy_names = ['paul.moore', 'tim.golden', 'ned.deily', 'lukasz.langa', 'zach.ware', 'steve.dower', 'pablogsal', 'miss-islington', 'Ghostkeeper']
pr_nums = ['27982', '27984', '27985', '28001', '28146']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45022'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

[zooba]

libffi is doing releases again! We're a few versions behind, so should pull in the latest. https://github.com/libffi/libffi/

Adding RMs for opinions on backporting, and Ned in case this impacts the macOS build.

[zooba]

This first PR is just to avoid accidentally upgrading old builds. Otherwise, as soon as I push the new build into the cpython-bin-deps repository, it'll take precedence.

This one needs backporting into 3.10 and 3.9, but should be a no-op.

[zooba]

New changeset 969ae7f by Steve Dower in branch 'main':
bpo-45022: Pin current libffi build to fixed version in preparation for upcoming update (GH-27982)
969ae7f

[miss-islington]

New changeset 399cd46 by Miss Islington (bot) in branch '3.9':
bpo-45022: Pin current libffi build to fixed version in preparation for upcoming update (GH-27982)
399cd46

[miss-islington]

New changeset db36fdb by Miss Islington (bot) in branch '3.10':
bpo-45022: Pin current libffi build to fixed version in preparation for upcoming update (GH-27982)
db36fdb

[zooba]

Realised that 3.8 needs the change to ensure it keeps using the same build of libffi. Obviously it won't be getting the new one (and since the new one is apparently a new API version, it may not even go into 3.10).

[ambv]

New changeset 8c3a10e by Steve Dower in branch '3.8':
bpo-45022: Pin current libffi build to fixed version in preparation for upcoming update (GH-27982) (GH-28001)
8c3a10e

[zooba]

New changeset 6f8bc46 by Steve Dower in branch 'main':
bpo-45022: Update libffi to 3.4.2 in Windows build (GH-28146)
6f8bc46

[zooba]

So on one hand, this change applies cleanly and it appears nothing needs to change to adopt the newer version.

On the other hand, because the libffi DLL has a different name, it changes the layout on disk. I know we don't do that (except in exceptional circumstances) after beta, but perhaps this one is safe enough? We certainly don't "support" directly accessing the libffi DLL, but it still could break users (if, for example, they load another native module that implicitly used the older libffi and would now fail to load when it's missing).

Any thoughts?

[zooba]

New changeset 4dc4300 by giovanniwijaya in branch 'main':
bpo-45022: Fix libffi DLL name in Windows installer sources (GH-28203)
4dc4300

[zooba]

Going to just decide that we won't backport the update. If a big enough security issue is found we can consider it, but it would have to justify the potential-but-unlikely breaking change for users who are relying on the name of the DLL.

[Ghostkeeper]

It seems this just broke our Windows build process of Python 3.8, since the cpython-bin-deps repository now contains only a libffi-8.lib while the the Python 3.8 branch still refers to libffi-7.lib in libffi.props:

cpython/PCbuild/libffi.props

Line 13 in 5a42a49

<_LIBFFIDLL Include="$(libffiOutDir)\libffi-7.dll" />

[zware]

The 3.8 branch has been updated to point to the libffi-3.3.0 tag; you can either update to the latest revision of 3.8 or pull in just 8c3a10e

[itachaaa]

It seems that libffi-3.4.2 is not supported by CPython 3.8, 3.9, and 3.10. Will this be considered later, Or wo have to have 3.11 to start supporting 3.4.2？

[iwannastay]

Going to just decide that we won't backport the update. If a big enough security issue is found we can consider it, but it would have to justify the potential-but-unlikely breaking change for users who are relying on the name of the DLL.

Do you mean that the version 3.9 of python dont support version 3.4.x of libffi?

#118171

We encountered a coredump with the versions above.