This ticket is for experimenting with an update to Cython 3, which entered the beta stage on 2023-02-25 after several years in alpha. (No release schedule has been published.)

• https://mail.python.org/pipermail/cython-devel/2019-November/thread.html (2019 - no response)
• https://groups.google.com/g/cython-users/c/WTHmGJ44aB0 (2022-01 "no concrete time plan")
• 3.0.0 roadmap? cython/cython#4022 (still no road map)

https://github.com/cython/cython/blob/master/CHANGES.rst

• Add missing cdef method declarations (for Cython 3) #34257 Add missing cdef method declarations (for Cython 3)
• Use Cython directive binding=True to get signatures for cython methods #26254 Use Cython directive binding=True to get signatures in help for cythonized built-in methods
• cython: Eliminate use of custom patches #32832 cython: Eliminate use of custom patches
• Type hints (__annotations__) and coercion/categories/Cython #30511 Type hints (__annotations__) and coercion/categories/Cython

See also:

• Backport PEP420 namespace package support from Cython 3 #34221 / Backport to 0.29.x: Add PEP420 namespace support cython/cython#4918 (Backport to 0.29.x: Add PEP420 namespace support)

Depends on #26254
Depends on #32832
Depends on #34257

CC: @kwankyu @williamstein @videlec @tscrim @tobiasdiez

Component: packages: standard

Keywords: upgrade

Branch/Commit: u/mkoeppe/meta_ticket__cython_3_0_0__unreleased_ @ 6c338f8

Issue created by migration from https://trac.sagemath.org/ticket/29863