From 1d303066229eb359c405575b3afcd6338aea52d5 Mon Sep 17 00:00:00 2001
From: Matthias Koeppe <mkoeppe@math.ucdavis.edu>
Date: Thu, 4 Jan 2024 14:48:36 -0800
Subject: [PATCH] src/bin/sage-cython: Repurpose as PEP 420 fixer, ship with
 sagemath-environment

---
 pkgs/sagemath-environment/pyproject.toml.m4 |  3 ++
 src/bin/sage-cython                         | 49 ++++++++-------------
 2 files changed, 21 insertions(+), 31 deletions(-)

diff --git a/pkgs/sagemath-environment/pyproject.toml.m4 b/pkgs/sagemath-environment/pyproject.toml.m4
index 44ddd190f99..c5488bc864d 100644
--- a/pkgs/sagemath-environment/pyproject.toml.m4
+++ b/pkgs/sagemath-environment/pyproject.toml.m4
@@ -50,6 +50,9 @@ script-files = [
     "bin/sage-version.sh",
     # Auxiliary script for invoking Python in the Sage environment
     "bin/sage-python",
+    # The following is freshly un-deprecated as a temporary workaround
+    # for defects in Cython 3.0.x support for PEP 420 implicit namespace packages
+    "bin/sage-cython",
     # Not included:
     # - bin/sage-env-config                  -- installed by sage_conf
     # - bin/sage-env-config.in               -- not to be installed
diff --git a/src/bin/sage-cython b/src/bin/sage-cython
index a52a729dd02..a189e44ce1d 100755
--- a/src/bin/sage-cython
+++ b/src/bin/sage-cython
@@ -1,39 +1,26 @@
-#!/usr/bin/env sage-python
+#!/usr/bin/env python
 
-# This script is a deprecated wrapper around the "cython" program.
-# It is deprecated since Issue #27041 (Sage 8.7) because one should
+# This script is a wrapper around the "cython" program.
+# It was deprecated in Issue #27041 (Sage 8.7) because one should
 # simply use "cython" directly. We display deprecation messages whenever
 # "sage-cython" does something different from plain "cython".
 #
 # A stronger deprecation warning was added in #29923 (Sage 9.2).
+#
+# In Sage 10.3, the deprecated functionality is removed permanently.
+# However, the script is un-deprecated and re-purposed as a temporary workaround
+# for defects in Cython 3.0.x support for PEP 420 implicit namespace packages,
+# see https://github.com/sagemath/sage/pull/36228
+#
+# This script can be used as a replacement for "cython".
+# For example, to have meson use it, set the environment variable
+# CYTHON to sage-cython./
+# https://github.com/mesonbuild/meson/blob/e4bbc630b67ef97ad842badd00855e64cff12e13/mesonbuild/envconfig.py#L91
 
-import os
-import sys
-args = sys.argv[1:]
-
-sys.stderr.write("WARNING: the script sage-cython is deprecated; use cython instead.\n")
-
-from sage.env import SAGE_SRC
-
-# args can have length 0, in case we're printing a usage message (see trac 12207)
-pyx_file = os.path.abspath(args[-1]) if len(args) else None
-include_sage_flags = False
-
-if pyx_file and pyx_file.startswith(SAGE_SRC):
-    sys.stderr.write("WARNING: in the future, sage --cython will not add special flags for files in Sage sources.\n")
-    include_sage_flags = True
-
-if '-sage' in args:
-    sys.stderr.write("WARNING: sage --cython -sage is deprecated.\n")
-    include_sage_flags = True
-    args.remove('-sage')
-elif '-no-sage' in args:
-    sys.stderr.write("WARNING: sage --cython -no-sage is deprecated, remove the -no-sage flag.\n")
-    include_sage_flags = False
-    args.remove('-no-sage')
+from sage.misc.package_dir import cython_namespace_package_support
 
-if include_sage_flags:
-    args = ['--embed-positions', '-I%s' % SAGE_SRC] + args
+# console scripts declared in https://github.com/cython/cython/blob/master/setup.py#L68
+from Cython.Compiler.Main import setuptools_main
 
-args.insert(0, 'sage-cython')
-os.execlp('cython', *args)
+with cython_namespace_package_support():
+     setuptools_main()